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Comparative law

2025-07-31T23:29:49Z

45.232.105.68:

{{short description|Study of relationship between legal systems}}
[[File:Map of the Legal systems of the world (en).png|thumb|Legal Systems of the World]]
'''Comparative law''' is the study of differences and similarities between the [[law]] and [[Legal system|legal systems]] of different countries. More specifically, it involves the study of the [[List of national legal systems|different legal systems]] (or "families") in existence around the world, including [[common law]], [[Civil law (legal system)|civil law]], [[socialist law]], [[Canon law]], [[Halakha|Jewish Law]], [[Sharia|Islamic law]], [[Hindu law]], and [[Chinese law]]. It includes the description and analysis of foreign legal systems, even where no explicit comparison is undertaken. The importance of comparative law has increased enormously in the present age of [[Internationalism (politics)|internationalism]] and [[economic globalization]].

==History==
The origins of modern comparative law can be traced back to [[Gottfried Wilhelm Leibniz]] in 1667 in his Latin-language book {{Lang|la|Nova Methodus Discendae Docendaeque Iurisprudentiae}} (New Methods of Studying and Teaching Jurisprudence).<ref>English translation: Leibniz (2017)</ref> Chapter 7 (Presentation of Law as the Project for all Nations, Lands and Times) introduces the idea of classifying Legal Systems into several families. A few years later, Leibniz introduced an idea of Language families.<ref>Leibniz, ''Dissertatio de origine Germanorum'' (1697), ''Epistolica de Historia Etymologica Dissertatio'', (1712).</ref>

Although every legal system is unique, comparative law through studies of their similarities and differences allows for classification of legal systems, wherein law families is the basic level of the classification. The main differences between law families are found in the source(s) of law, the role of court precedents, the origin and development of the legal system. [[Montesquieu]] is generally regarded as an early founding figure of comparative law. His comparative approach is obvious in the following excerpt from Chapter III of Book I of his masterpiece, ''[[De l'esprit des lois]]'' (1748; first translated by Thomas Nugent, 1750):<ref>{{cite book|title=The Spirit of Law|author=Baron De Montesquieu|place=New York |publisher=Hafner |year=1949}}</ref>{{blockquote|[T]he political and civil laws of each nation ... should be adapted in such a manner to the people for whom they are framed that it should be a great chance if those of one nation suit another.

They should be in relation to the nature and principle of each government: whether they form it, as may be said of politic laws; or whether they support it, as in the case of civil institutions.

They should be in relation to the climate of each country, to the quality of its soil, to its situation and extent, to the principal occupation of the natives, whether husbandmen, huntsmen, or shepherds: they should have relation to the degree of liberty which the constitution will bear; to the religion of the inhabitants, to their inclinations, riches, numbers, commerce, manners, and customs.}}

Also, in Chapter XI (entitled 'How to compare two different Systems of Laws') of Book XXIX, discussing the French and English systems for punishment of false witnesses, he advises that "to determine which of those systems is most agreeable to reason, we must take them each as a whole and compare them in their entirety." Yet another place where Montesquieu's comparative approach is evident is the following, from Chapter XIII of Book XXIX:

[[Image:HSMaine.jpg|thumbnail|Sir [[Henry James Sumner Maine]], British jurist and first professor of comparative law at [[University of Oxford|Oxford]]]]
{{blockquote|As the civil laws depend on the political institutions, because they are made for the same society, whenever there is a design of adopting the civil law of another nation, it would be proper to examine beforehand whether they have both the same institutions and the same political law.}}

The modern founding figure of comparative and [[legal anthropology|anthropological]] jurisprudence was Sir [[Henry Maine]], a British jurist and legal historian.<ref>{{cite book|url=https://books.google.com/books?id=iEk-Fpdw4MYC|title=Sir Henry Maine: A Study in Victorian Jurisprudence|author=Raymond Cocks|year=2004|publisher=Cambridge University Press|page=34|isbn=9780521524964}}</ref> In his 1861 work ''[[Ancient Law|Ancient Law: Its Connection with the Early History of Society, and Its Relation to Modern Ideas]]'', he set out his views on the development of legal institutions in primitive societies and engaged in a comparative discussion of [[Far East|Eastern]] and [[Western culture|West]]ern legal traditions. This work placed comparative law in its historical context and was widely read and influential.

The first university course on the subject was established at the [[University of Oxford]] in 1869, with Maine taking up the position of professor.<ref>{{Cite web|url=https://www.britannica.com/EBchecked/topic/358681/Sir-Henry-Maine|title=Sir Henry Maine|access-date=2012-12-17}}</ref>

Comparative law in the US was brought by a legal scholar fleeing persecution in Germany, [[Rudolf Schlesinger]]. Schlesinger eventually became professor of comparative law at [[Cornell Law School]] helping to spread the discipline throughout the US.{{citation needed|date=May 2023}}

==Purpose==
{{One source|section|date=June 2023}}
Comparative law is an academic discipline that involves the study of legal systems, including their constitutive elements and how they differ,<ref>See, e.g., Kristoffel Grechenig & Martin Gelter, The Transatlantic Divergence in Legal Thought: American Law and Economics vs. German Doctrinalism, [http://ssrn.com/abstract=1161168 ''Hastings International and Comparative Law Review 2008, vol. 31, p. 295-360''] comparing German style and U.S. style legal scholarship</ref> and how their elements combine into a system.

Several disciplines have developed as separate branches of comparative law, including comparative [[constitutional law]], comparative [[administrative law]], comparative [[Civil law (private law)|civil law]] (in the sense of the law of [[tort]]s, [[contract]]s, [[Property law|property]] and [[Law of obligations|obligations]]), comparative [[commercial law]] (in the sense of [[Companies law|business organisations]] and trade), and comparative [[criminal law]]. Studies of these specific areas may be viewed as micro- or macro-comparative legal analysis, i.e. detailed comparisons of two countries, or broad-ranging studies of several countries. Comparative civil law studies, for instance, show how the law of private relations is organised, interpreted and used in different systems or countries. The purposes of comparative law are:
* To attain a deeper knowledge of the legal systems in effect
* To perfect the legal systems in effect
* Possibly, to contribute to a unification of legal systems, of a smaller or larger scale (cf. for instance, the [[UNIDROIT]] initiative)

==Relationship with other legal subjects==
Comparative law is different from general [[jurisprudence]] (i.e. legal theory) and from [[public international law|public]] and [[private international law|private]] international law. However, it helps inform all of these areas of normativity.

For example, comparative law can help international legal institutions, such as those of the [[United Nations System]], in analyzing the laws of different countries regarding their treaty obligations. Comparative law would be applicable to private international law when developing an approach to interpretation in a conflicts analysis. Comparative law may contribute to legal theory by creating categories and concepts of general application. Comparative law may also provide insights into the question of [[legal transplants]], i.e. the transplanting of law and legal institutions from one system to another. The notion of [[legal transplants]] was coined by [[Alan Watson (legal scholar)|Alan Watson]], one of the world's renowned legal scholars specializing in comparative law. [[Gunther Teubner]] expanded the notion of legal transplantation to include ''legal irritation'': Rather than smoothly integrating into domestic legal systems, a foreign rule disrupts established norms and societal arrangements. This disruption sparks an evolution where the external rule's meaning is redefined and where significant transformations within the internal context are triggered.<ref>{{Cite journal |last=Teubner |first=Gunther |date=1998 |title=Legal Irritants: Good Faith in British Law or How Unifying Law Ends Up in New Divergences |url=https://papers.ssrn.com/sol3/papers.cfm?abstract_id=876950 |journal=The Modern Law Review |volume=61 |issue=1 |pages=11–32|doi=10.1111/1468-2230.00125 |ssrn=876950 }}</ref> Lasse Schuldt added that irritation is not spontaneous, but requires institutional drivers.<ref>{{Cite journal |last=Schuldt |first=Lasse |date=2023-09-25 |title=Driving Irritation: Thailand's Supreme Court and the English Roots of Corporate Criminal Liability |url=https://www.cambridge.org/core/journals/asian-journal-of-comparative-law/article/driving-irritation-thailands-supreme-court-and-the-english-roots-of-corporate-criminal-liability/A5C74EAC37FB689A03E54F5EBB6B1409/share/bb0af930ebdb2439ba3e100ae30a2ee0cf5d32ab19310b744e9142b2f1e3b2c5 |journal=Asian Journal of Comparative Law |volume=19 |language=en |pages=142–158 |doi=10.1017/asjcl.2023.29 |s2cid=263007531 |issn=2194-6078|url-access=subscription }}</ref>

Also, the usefulness of comparative law for [[sociology of law]] and [[law and economics]] (and vice versa) is very large. The comparative study of the various legal systems may show how different legal regulations for the same problem function in practice. Conversely, sociology of law and law & economics may help comparative law answer questions, such as:
* How do regulations in different legal systems really function in the respective societies?
* Are legal rules comparable?
* How do the similarities and differences between legal systems get explained?

==Classifications of legal systems==
===David===
[[René David]]<ref>''Traité élémentaire de droit civil comparé : Introduction à l'étude des droits étrangers et à la méthode comparative'' - in French; Paris, 1950</ref> proposed the classification of legal systems, according to the different ideology inspiring each one, into five groups or families:<ref name="VARGA-p54-DAVID">{{cite book |last=Varga |first=Csaba |date=2012 |title=COMPARATIVE LEGAL CULTURES |url=https://philarchive.org/archive/VARCLC |location=Budapest |publisher= |pages=54–55 |isbn=9789632773377}}</ref>
* [[Western world|Western]] laws, a group subdivided into the:
** [[Civil law (legal system)|Civil law subgroup]] (whose jurisprudence is based on post-classical [[Roman Law]])
** [[Common law|Common law subgroup]] (originating in [[English law]])
* [[Law of the Soviet Union|Soviet Law]]
* [[Sharia|Muslim Law]]
* [[Hindu law|Hindu Law]]
* [[Chinese law|Chinese Law]]
* [[Jewish Law]]

Especially with respect to the aggregating by David of the Civil and Common laws into a single family, David argued that the antithesis between the Common law and Civil law systems, is of a technical rather than of an ideological nature. Of a different kind is, for instance, the antithesis between, say, Italian and American laws, and of a different kind than between the Soviet, Muslim, Hindu, or Chinese laws. According to David, the Civil law legal systems included those countries where legal science was formulated according to Roman law, whereas Common law countries are those dominated by judge-made law. The characteristics that he believed uniquely differentiate the Western legal family from the other four are:
* liberal democracy
* capitalist economy
* Christian religion

===Arminjon, Nolde, and Wolff===
Arminjon, Nolde, and Wolff<ref>''Traité de droit comparé'' – in French; Paris 1950–1952</ref> believed that, for purposes of classifying the (then) contemporary legal systems of the world, it was required that those systems ''per se'' get studied, irrespective of external factors, such as geographical ones. They proposed the classification of legal system into seven groups, or so-called 'families', in particular the:<ref name="VARGA-p59-WOLFF">{{cite book |last=Varga |first=Csaba |date=2012 |title=COMPARATIVE LEGAL CULTURES |url=https://philarchive.org/archive/VARCLC |location=Budapest |publisher= |page=59 |isbn=9789632773377}}</ref>
* [[Law of France|French group]], under which they also included the countries that codified their law either in 19th or in the first half of the 20th century, using the [[Napoleonic code|Napoleonic ''code civil'']] of year 1804 as a model; this includes countries and jurisdictions such as Italy, Portugal, Spain, Romania, [[Louisiana]], various South American states such as Brazil, [[Quebec]], [[Saint Lucia]], the [[Ionian Islands]], Egypt, and [[Lebanon]]
* [[Law of Germany|German group]]
* Scandinavian group, comprising the laws of Denmark, Norway, Sweden, Finland, and Iceland
* [[Common law|English group]], including, ''inter alia'', England, the United States, Canada, Australia, and New Zealand
* Russian group
* [[Sharia|Islamic group]] (used in the [[Muslim world]])
* [[Hindu law|Hindu group]]

===Zweigert and Kötz===
Konrad Zweigert and [[Hein Kötz]]<ref>Konrad Zweigert, Hein Kötz: ''An Introduction to Comparative Law'', translation from the German original: ''Einführung in die Rechtsvergleichung auf dem Gebiete des Privatrechts'' by Tony Weir, 3rd edition; Oxford, 1998. {{ISBN|9780198268598}}.</ref> propose a different, multidimensional methodology for categorizing laws, i.e. for ordering families of laws. They maintain that, to determine such families, five criteria should be taken into account, in particular: the historical background, the characteristic way of thought, the different institutions, the recognized sources of law, and the dominant ideology. Using the aforementioned criteria, they classify the legal systems of the world into six families:<ref name="VARGA-p63-KOTZ">{{cite book |last=Varga |first=Csaba |date=2012 |title=COMPARATIVE LEGAL CULTURES |url=https://philarchive.org/archive/VARCLC |location=Budapest |publisher= |pages=63–64 |isbn=9789632773377}}</ref>
* [[Roman law|Roman family]]
* [[Law of Germany|German family]]
* [[Common law|Common law family]]
* Nordic family
* Family of the laws of the [[Far East]] (China and Japan)
* Religious family (Jewish, Muslim, and Hindu law)

Up to the second German edition of their introduction to comparative law, Zweigert and Kötz also used to mention [[Socialist law|Soviet or socialist law]] as another family of laws.<ref>Konrad Zweigert, Hein Kötz: ''Einführung in die Rechtsvergleichung''. 3rd edition. 1996. Mohr Siebeck. Tübingen. 1996. {{ISBN|3-16-146548-2}} (Hein Kötz mentions in the preface to the third edition on page V that the fall of "soviet communism" also made an end to the "soviet family of laws", which made it possible to save some 60 pages as compared to the 2nd edition).</ref>

===Glenn===
[[H. Patrick Glenn]]<ref>''Legal Traditions of the World'' - Oxford University Press, 2000</ref> proposed the classification of legal systems places national laws in the broader context of major legal tradition:<ref name="VARGA-p68-GLENN">{{cite book |last=Varga |first=Csaba |date=2012 |title=COMPARATIVE LEGAL CULTURES |url=https://philarchive.org/archive/VARCLC |location=Budapest |publisher= |page=68 |isbn=9789632773377}}</ref>
* Chthonic (or indigenous) law
* [[Talmudic law]]
* [[Islamic law]]
* [[Hindu law]]
* [[Chinese law#Confucianism|Confucianism law]]
* [[Civil law (legal system)|Civil law]]
* [[Common law]]

==Professional associations==
* [[American Association of Law Libraries]]
* [[American Society of Comparative Law]]
* [[International Association of Judicial Independence and World Peace]]
* [[International Association of Procedural Law]]
* [[International Law Association]]

==Comparative law periodicals==
* ''[[American Journal of Comparative Law]]''
* ''[[German Law Journal]]''
* ''[[Journal of Comparative Legislation and International Law]]''
* [http://www.wildy.com/isbn/1477-0814/journal-of-comparative-law-annual-subscription ''The Journal of Comparative Law'']

==See also==
* [[Annual Bulletin (Comparative Law Bureau)|''Annual Bulletin'' of the Comparative Law Bureau]] (American Bar Association: 1908–1914, 1933), the first comparative law journal in the U.S.
* [[Comparative criminal justice]]
* [[Comparative law wiki]], online wikis where jurists can complete questionnaires regarding their home legal system
* [[Friedrich Carl von Savigny]] (1779–1861) – a German legal scholar who wrote on comparative law
* [[List of national legal systems]]
* [[Rule according to higher law]]
* [[Rule of law]]

== References ==
=== Notes ===
{{reflist|20em|group=nb}}

=== Citations ===
{{Reflist|20em}}

=== Sources ===
* Billis, Emmanouil. 'On the methodology of comparative criminal law research: Paradigmatic approaches to the research method of functional comparison and the heuristic device of ideal types', ''Maastricht Journal of European and Comparative Law'' 6 (2017): 864–881.
* [[H Collins]], 'Methods and Aims of Comparative Contract Law' (1989) 11 OJLS 396.
* Cotterrell, Roger (2006). ''Law, Culture and Society: Legal Ideas in the Mirror of Social Theory''. Aldershot: Ashgate.
* De Cruz, Peter (2007) ''Comparative Law in a Changing World'', 3rd edn (1st edn 1995). London: Routledge-Cavendish.
* Donahue, Charles (2008) 'Comparative Law before the "Code Napoléon"' in ''The Oxford Handbook of Comparative Law''. Eds. Mathias Reimann & Reinhard Zimmermann. Oxford: Oxford University Press.
* Glanert, Simone (2008) 'Speaking Language to Law: The Case of Europe', ''Legal Studies'' 28: 161–171.
* Hamza, Gabor (1991). ''Comparative Law and Antiquity''. Budapest: Akademiai Kiado.
* Husa, Jaakko. ''A New Introduction to Comparative Law''. Oxford–Portland (Oregon): Hart, 2015.
* [[O Kahn-Freund]], 'Comparative Law as an Academic Subject' (1966) 82 LQR 40.
* Kischel, Uwe. ''Comparative Law''. Trans. Andrew Hammel. Oxford: Oxford University Press, 2019.
* Legrand, Pierre (1996). 'European Legal Systems Are Not Converging', ''International and Comparative Law Quarterly'' 45: 52–81.
* Legrand, Pierre (1997). 'Against a European Civil Code', ''Modern Law Review'' 60: 44–63.
* Legrand, Pierre & Roderick Munday, eds. (2003). ''Comparative Legal Studies: Traditions and Transitions''. Cambridge: Cambridge University Press.
* Legrand, Pierre (2003). 'The Same and the Different', in ''Comparative Legal Studies: Traditions and Transitions''. Eds. Pierre Legrand & Roderick Munday. Cambridge: Cambridge University Press.
* Leibniz, Gottffried Wilhelm (2017) ''The New Method of Learning and Teaching Jurisprudence... Translation of the 1667 Frankfurt Edition''. Clark, NJ: Talbot Publishing.
* Lundmark, Thomas. ''Charting the divide between common and civil law''. Oxford University Press, 2012.
* MacDougal, M.S. 'The Comparative Study of Law for Policy Purposes: Value Clarification as an Instrument of Democratic World Order' (1952) 61 Yale Law Journal 915 (difficulties and requirements of good comparative law).
* {{cite book |title=Schlesinger's Comparative Law: Cases, Text, Materials|last=Mattei|first=Ugo |author2=Teemu Ruskola |author3=Antonio Gidi |year=2009 |publisher=Foundation |location=London|isbn=978-1-58778-591-7}}.
* [[Menski Werner]] (2006) ''Comparative Law in a Global Context: the Legal Traditions of Asia and Africa''. Cambridge: Cambridge University Press.
* Örücü, Esin & David Nelken, eds. ''Comparative Law: A Handbook''. Oxford: Hart, 2007.
* Örücü, Esin. ''The enigma of comparative law: variations on a theme for the twenty-first century''. Leiden: Martinus Nijhoff, 2004.
* Reimann, Mathias & Reinhard Zimmermann, eds. ''The Oxford Handbook of Comparative Law'', 2nd edn. Oxford: Oxford University Press, 2019 (1st edn. 2008).
* Samuel, Geoffrey. ''An Introduction to Comparative Law Theory and Method''. Oxford: Hart, 2014.
* Siems, Mathias. ''Comparative Law''. Cambridge: Cambridge University Press, 2014.
* Watson, Alan. ''Legal Transplants: An Approach to Comparative Law'', 2nd edn. University of Georgia Press, 1993.
* Zweigert, Konrad & Hein Kötz. ''An Introduction to Comparative Law'', 3rd edn. Trans. Tony Weir. Oxford: Oxford University Press, 1998.
;Legal systems
* {{cite book|title=Major Legal Systems in the World Today: An Introduction to the Comparative Study of Law|last=David|first=René|author2=Brierley, John E. C.|year=1985|publisher=Stevens|location=London|isbn=0-420-47340-8|url-access=registration|url=https://archive.org/details/majorlegalsystem00davi}}.
* Glendon, Mary Ann, Paolo G. Carozza, & Colin B. Picker. ''Comparative Legal Traditions in a Nutshell'', 4th edn. West Academic Publishing, 2015.
* Glendon, Mary Ann, Paolo G. Carozza, & Colin B. Picker (2014). ''Comparative Legal Traditions: Text, Materials and Cases on Western Law'', 4th edn. West Academic Publishing.
* Glenn, H. Patrick. ''Legal Traditions of the World'', 5th edn. Oxford: Oxford University Press, 2014 (1st edn 2000).
;Fields
* Bignami, Fracesca & David Zaring, eds. ''Comparative Law and Regulation: Understanding the Global Regulatory Process''. Edward Elgar, 2018.
* Graziano, Thomas Kadner. ''Comparative Contract Law: Cases, Materials and Exercises'', 2nd edn. Edward Elgar, 2019.
* Kozolchyk, Boris. ''Comparative Commercial Contracts: Law, Culture and Economic Development'', 2nd edn. West Academic Publishing, 2018.
* Nelken, David, ed. ''Contrasting Criminal Justice: Getting from Here to There''. Aldershot: Ashgate/Dartmouth, 2000.
* Roberts, Anthea et al., eds. ''Comparative International Law''. Oxford: Oxford University Press, 2018.

==External links==
* [https://web.archive.org/web/20190809113731/http://www.alanwatson.org/ Alan Watson Foundation]
* [https://law.tulane.edu/centers/eason Eason Weinmann Center for International and Comparative Law at Tulane University Law School]
* [https://n-lex.europa.eu/n-lex/index?lang=en European Union national law portal]
* [https://www.global-regulation.com/ Global-Regulation search engine]
* [https://web.archive.org/web/20100130093740/http://www.iuscomparatum.org/AIDC International Academy of Comparative Law] {{in lang|fr}}
* [http://www.iacl-aidc.org International Association of Constitutional Law]
* [http://www.internationalconstitutionallaw.net International Constitutional Law] {{Webarchive|url=https://web.archive.org/web/20210518150439/http://internationalconstitutionallaw.net/ |date=2021-05-18 }}
* [https://web.archive.org/web/20190422114950/http://www.juriglobe.ca/eng/index.php JuriGlobe]
* [https://www.mpil.de/en/pub/news.cfm Max Planck Institute for Comparative Public Law and International Law]
* [https://ouclf.law.ox.ac.uk/ Oxford University Comparative Law Forum]
* [https://www.loc.gov/law/help/guide/nations.php US Library of Congress Guide to Law Online: Nations]
* [https://blogs.loc.gov/law/category/global-law/ US Library of Congress Global Law blog]
{{law}}

{{Authority control}}

[[Category:Comparative law| ]]
[[Category:Academic disciplines]]
[[Category:Jurisprudence]]

Hydrofoil

2025-07-24T19:31:35Z

45.232.105.68:

{{Short description|Type of fast watercraft and the name of the technology it uses}}
{{For|other types of foil|Foil (fluid mechanics)}}

{{Use dmy dates|date=July 2021}}
A '''hydrofoil''' is a lifting surface, or [[foil (fluid mechanics)|foil]], that operates in water. They are similar in appearance and purpose to [[aerofoil]]s used by [[aeroplane]]s. [[Boat]]s that use hydrofoil technology are also simply termed hydrofoils. As a hydrofoil craft gains speed, the hydrofoils lift the boat's [[Hull (watercraft)|hull]] out of the water, decreasing [[Drag (physics)|drag]] and allowing greater speeds.

==Description==
The hydrofoil usually consists of a [[wing]]like structure mounted on [[strut]]s below the [[hull (watercraft)|hull]], or across the keels of a [[catamaran]] in a variety of boats (see illustration). As a hydrofoil-equipped watercraft increases in speed, the hydrofoil elements below the hull(s) develop enough [[lift (force)|lift]] to raise the hull out of the water, which greatly reduces hull [[drag (physics)|drag]]. This provides a corresponding increase in [[speed]] and [[fuel efficiency]].

Wider adoption of hydrofoils is prevented by the increased complexity of building and maintaining them. Hydrofoils are generally prohibitively more expensive than conventional watercraft above a certain displacement, so most hydrofoil craft are relatively small, and are mainly used as high-speed passenger ferries, where the relatively high passenger fees can offset the high cost of the craft itself. However, the design is simple enough that there are many [[human-powered hydrofoil]] designs. Amateur experimentation and development of the concept is popular.<ref>{{cite AV media|url=https://www.youtube.com/results?search_query=hydrofoil+design&search=Search&gl=CA&hl=en|title=hydrofoil design - YouTube}}</ref>

==Hydrodynamic mechanics==
{{unreferenced section|date=March 2016}}
[[File:Hydrofoil types.svg|thumb|The two types of hydrofoils: surface-piercing and fully submerged]]

Since air and water are governed by similar [[fluid dynamics|fluid equations]]—albeit with different levels of [[viscosity]], [[density]], and [[compressible flow|compressibility]]—the hydrofoil and [[airfoil]] (both types of [[foil (fluid mechanics)|foil]]) create [[lift (force)|lift]] in identical ways. The foil shape moves smoothly through the water, deflecting the flow downward, which, following the [[Euler equations (fluid dynamics)|Euler equations]], exerts an upward force on the foil. This turning of the water creates higher pressure on the bottom of the foil and reduced pressure on the top. This pressure difference is accompanied by a velocity difference, via [[Bernoulli's principle]], so the resulting flow field about the foil has a higher average velocity on one side than the other.

When used as a lifting element on a hydrofoil boat, this upward force lifts the body of the vessel, decreasing drag and increasing speed. The lifting force eventually balances with the weight of the craft, reaching a point where the hydrofoil no longer lifts out of the water but remains in equilibrium. Since wave resistance and other impeding forces such as various types of [[drag (physics)]] on the hull are eliminated as the hull lifts clear, turbulence and drag act increasingly on the much smaller surface area of the hydrofoil, and decreasingly on the hull, creating a marked increase in speed.<ref>{{cite web
| url =http://web.mit.edu/2.972/www/reports/hydrofoil/hydrofoil.html
| title =Hydrofoils
| last =Rosado
| first =Tina
| date =1999
| website =Reports on How Things Work
| publisher =Massachusetts Institute of Technology
| access-date =11 December 2016
}}</ref>

===Foil configurations===
Early hydrofoils used V-shaped foils. Hydrofoils of this type are known as "surface-piercing" since portions of the V-shape hydrofoils rise above the water surface when foilborne. Some modern hydrofoils use fully submerged inverted T-shape foils. Fully submerged hydrofoils are less subject to the effects of wave action, and, therefore, more stable at sea and more comfortable for crew and passengers. This type of configuration, however, is not self-stabilizing. The [[angle of attack]] on the hydrofoils must be adjusted continuously to changing conditions, a control process performed by sensors, a computer, and active surfaces.

== History ==
[[File:Forlanini Idroplano-Forlani Hydrofoil 1910.jpg|thumb|[[Enrico Forlanini|Forlanini's]] hydrofoil over [[Lake Maggiore]], 1906]]

=== Prototypes ===

The first evidence of a hydrofoil on a vessel appears on a British patent granted in 1869 to Emmanuel Denis Farcot, a Parisian. He claimed that "adapting to the sides and bottom of the vessel a series or inclined planes or wedge formed pieces, which as the vessel is driven forward will have the effect of lifting it in the water and reducing the draught.".<ref>{{Cite web|url=http://www.histarmar.com.ar/InfGral/Hidroalas/PrimerosHydrofoils.htm|title=Early Hydrofoils|website=histarmar.com.ar|access-date=2019-02-26}}</ref> Italian inventor [[Enrico Forlanini]] began work on hydrofoils in 1898 and used a "ladder" foil system. Forlanini obtained patents in Britain and the United States for his ideas and designs.<ref>{{cite web|url = http://www.foils.org/gallery/forlani.htm|title = Forlanini|publisher = International Hydrofoil Society|access-date = 22 January 2016|website = The Hydrofoil Resource Site|first = Malin|last = Dixon|url-status = dead|archive-url = https://web.archive.org/web/20170118154755/http://www.foils.org/gallery/forlani.htm|archive-date = 18 January 2017}}</ref><ref>[https://books.google.com/books?id=-t0DAAAAMBAJ&pg=PA927 "Italian Hydroplane of Curious Type."] ''Popular Mechanics'', December 1911, p. 927.</ref>

Between 1899 and 1901, British boat designer [[John Isaac Thornycroft|John Thornycroft]] worked on a series of models with a stepped hull and single bow foil. In 1909 his company built the full scale {{convert|22|ft|m|adj=on}} long boat, ''Miranda III''. Driven by a {{convert|60|hp|abbr=on}} engine, it rode on a bowfoil and flat stern. The subsequent ''Miranda IV'' was credited with a speed of {{convert|35|kn|km/h mph|abbr=on}}.<ref>{{cite web | title=Thornycroft Model Collection| url=http://www.hovercraft-museum.org/musthorn1.html | access-date=9 September 2009 |archive-url=https://web.archive.org/web/20090624185932/http://www.hovercraft-museum.org/musthorn1.html |archive-date=24 June 2009}}</ref>

[[Image:Bell HD-4.jpg|thumb|[[Alexander Graham Bell]]'s ''[[HD-4]]'' on a test run, c. 1919]]

In May 1904 a hydrofoil boat was described being tested on the [[River Seine]] "in the neighbourhood of [[Paris]]".<ref>The Principle of the Aeroplane Applied to the Boat, The Automotor Journal, 21 May 1904, p21</ref> This boat was designed by [[Charles de Lambert (aviator)|Comte de Lambert]].<ref>The Hydroplane or Gliding Boat, St James's Gazette, 24 May 1904, p16</ref> This had 5 variable pitch fins on the hull beneath the water so inclined that when the boat begins to move "the boat rises and the planes come to the surface" with the result that "it skims over the surface with little but the propellers beneath the surface". The boat had twin hulls 18-foot long connected by a single deck 9-foot wide, and was fitted with a 14HP [[De Dion-Bouton]] motor, the boat was reported to have reached 20 mph. It was stated that "The boat running practically on its fins resembles an aeroplane".

A March 1906 [[Scientific American]] article by American hydrofoil pioneer William E. Meacham explained the basic principle of hydrofoils. [[Alexander Graham Bell]] considered the invention of the [[Hydroplane (boat)|hydroplane]] (now regarded as a distinct type, but also employing lift) a very significant achievement, and after reading the article began to sketch concepts of what is now called a hydrofoil boat. With his chief engineer [[Frederick W. Baldwin|Casey Baldwin]], Bell began hydrofoil experiments in the summer of 1908. Baldwin studied the work of the Italian inventor [[Enrico Forlanini]] and began testing models based on those designs, which led to the development of hydrofoil watercraft. During Bell's world tour of 1910–1911, Bell and Baldwin met with Forlanini in Italy, where they rode in his hydrofoil boat over [[Lake Maggiore]]. Baldwin described it as being as smooth as flying.

On returning to Bell's large laboratory at his [[Beinn Bhreagh, Nova Scotia|Beinn Bhreagh]] estate near [[Baddeck, Nova Scotia]], they experimented with a number of designs, culminating in Bell's ''[[HD-4]]''. Using [[Renault]] engines, a top speed of {{convert|87|km/h|kn mph|abbr=on}} was achieved, accelerating rapidly, taking waves without difficulty, steering well and showing good stability. Bell's report to the [[United States Navy]] permitted him to obtain two {{convert|260|kW|hp|abbr=on}} engines. On 9 September 1919 the ''HD-4'' set a world marine speed record of {{convert|114|km/h|kn mph|abbr=on}}, which stood for two decades.<ref name="canada encyclopedia">{{Cite encyclopedia |title=Hydrofoil |url=http://www.thecanadianencyclopedia.com/articles/hydrofoil |archive-url=https://web.archive.org/web/20120504002603/http://www.thecanadianencyclopedia.com/articles/hydrofoil |url-status=dead |archive-date=4 May 2012 |publisher=Historica Canada |encyclopedia=The Canadian Encyclopedia}}</ref> A full-scale replica of the ''HD-4'' is viewable at the [[Alexander Graham Bell#Legacy and honors|Alexander Graham Bell National Historic Site]] museum in Baddeck, Nova Scotia.

In the early 1950s an English couple built the ''White Hawk'', a jet-powered hydrofoil water craft, in an attempt to beat the absolute water speed record.<ref>[https://books.google.com/books?id=8NsDAAAAMBAJ&dq=1954+Popular+Mechanics+January&pg=PA70 "Jet Hydrofoil Shoots At World Record"] ''Popular Mechanics'', August 1953, pp. 70-71</ref> However, in tests, ''White Hawk'' could barely top the record breaking speed of the 1919 ''HD-4''. The designers had faced an engineering phenomenon that limits the top speed of even modern hydrofoils: [[cavitation]] disturbs the lift created by the foils as they move through the water at speed above {{convert|60|kn|km/h mph|abbr=on}}, bending the lifting foil.<ref>''The World Water Speed Record'' by Leo Villa and Kevin Desmond, 1976</ref>

[[File:Fully submerged hydrofoils self-stabilizing system.svg|thumb|A schematic illustration of self-stabilizing systems for fully submerged hydrofoils. Its computer gathers data for the boom position and current water level to determine the required flap position.]]

=== First passenger boats ===

German engineer Hanns von Schertel worked on hydrofoils prior to and during [[World War II]] in [[Germany]]. After the war, the Russians captured Schertel's team. As Germany was not authorized to build fast boats, Schertel went to [[Switzerland]], where he established the Supramar company. In 1952, Supramar launched the first commercial hydrofoil, PT10 "Freccia d'Oro" (Golden Arrow), in Lake Maggiore, between Switzerland and [[Italy]]. The PT10 is of surface-piercing type, it can carry 32 passengers and travel at {{convert|35|kn|km/h mph}}. In 1968, the Bahraini born banker [[Hussain Najadi]] acquired the Supramar AG and expanded its operations into Japan, Hong Kong, Singapore, the UK, Norway and the US. [[General Dynamics]] of the United States became its licensee, and the Pentagon awarded its first R&D naval research project in the field of [[supercavitation]]. [[Hitachi]] Shipbuilding of Osaka, Japan, was another licensee of Supramar, as well as many leading ship owners and shipyards in the OECD countries.

From 1952 to 1971, Supramar designed many models of hydrofoils: PT20, PT50, PT75, PT100 and PT150. All are of surface-piercing type, except the PT150 combining a surface-piercing foil forward with a fully submerged foil in the aft location. Over 200 of Supramar's design were built, most of them by Rodriquez (headed at the time by Engineer Carlo Rodriquez in [[Sicily]], Italy.

During the same period the [[Soviet Union]] experimented extensively with hydrofoils, constructing hydrofoil river boats and [[ferries]] with streamlined designs during the cold war period and into the 1980s. Such vessels include the [[Raketa (hydrofoil)|Raketa]] (1957) type, followed by the larger [[Meteor (hydrofoil)|Meteor]] type and the smaller [[Voskhod (hydrofoil)|Voskhod]] type. One of the most successful Soviet designer/inventor in this area was [[Rostislav Alexeyev]], who some consider the 'father' of the modern hydrofoil due to his 1950s era high speed hydrofoil designs.{{Citation needed|date=August 2009}} Later, circa 1970s, Alexeyev combined his hydrofoil experience with the [[Ground effect in aircraft|surface effect]] principle to create the [[Ekranoplan]]. Extensive investment in this type of technology in the USSR resulted in the largest civil hydrofoil fleet in the world and the making of the Meteor type, the most successful hydrofoil in history, with more than 400 units built.

<gallery class="center" caption="Soviet civil hydrofoils" widths="180px" heights="120px">
Peterhof hydrofoil (18272163540).jpg|[[Voskhod (hydrofoil)|Voskhod]]
Meteor boat on Neva Bay.jpg|[[:ru:Метеор (теплоход)|Meteor]]
Raketa-185 on Khimki Reservoir 6-jun-2014 02.jpg|[[Raketa (hydrofoil)|Raketa]]
Polesye-1 (ship, 1986, Gomel, 7).jpg|[[:ru:Полесье (теплоход)|Polesye]]
Kizhi 06-2017 img30 Kometa-17 hydrofoil.jpg|[[:ru:Комета (теплоход)|Kometa]]
</gallery>

In 1961, [[SRI International]] issued a study on "The Economic Feasibility of Passenger Hydrofoil Craft in US Domestic and Foreign Commerce".<ref name="Feasibility">{{cite web |title = The Economic Feasibility of Passenger Hydrofoil Craft in U.S. Domestic and Foreign Commerce.|author = SRI International|author-link = SRI International|url = http://ntlsearch.bts.gov/tris/record/tris/00026416.html|year = 1961|access-date = 9 September 2009|archive-url = https://web.archive.org/web/20120301104231/http://ntlsearch.bts.gov/repository/record/tris/00026416.html|archive-date = 1 March 2012}}</ref> Commercial use of hydrofoils in the US first appeared in 1961 when two commuter vessels were commissioned by [[Harry Gale Nye, Jr.]]'s North American Hydrofoils to service the route from Atlantic Highlands, New Jersey to the financial district of Lower Manhattan.<ref>{{cite web| title=Enterprise|first = Malin | last= Dixon| url=http://www.foils.org/gallery/enterpr.htm| access-date=9 September 2009| url-status=dead| archive-url=https://web.archive.org/web/20100428050743/http://www.foils.org/gallery/enterpr.htm| archive-date=28 April 2010}}</ref>

==Military usage==

===Germany===
A 17-ton German craft ''VS-6 Hydrofoil'' was designed and constructed in 1940, completed in 1941 for use as a mine layer; it was tested in the [[Baltic Sea]], producing speeds of 47 knots. Tested against a standard [[E-boat]] over the next three years it performed well but was not brought into production. Being faster it could carry a higher payload and was capable of travelling over minefields but was prone to damage and noisier.<ref>{{cite book |title=Channel Islands Occupation Review No 34 |publisher=Channel Islands Occupation Society |date=2006}}</ref>

===Canada===
[[File:HMCS Bras d'Or 03.jpg|thumb|HMCS ''Bras d'Or'', a military concept hydrofoil.]]
In Canada during World War II, Baldwin worked on an experimental [[smoke screen|smoke laying]] hydrofoil (later called the Comox Torpedo) that was later superseded by other smoke-laying technology and an experimental target-towing hydrofoil. The forward two foil assemblies of what is believed to be the latter hydrofoil were salvaged in the mid-1960s from a derelict hulk in Baddeck, Nova Scotia by Colin MacGregor Stevens. These were donated to the Maritime Museum in Halifax, Nova Scotia.

The [[Canadian Forces Maritime Command|Canadian Armed Forces]] built and tested a number of hydrofoils (e.g., Baddeck and two vessels named ''Bras d'Or''), which culminated in the high-speed anti-submarine hydrofoil [[HMCS Bras d'Or (FHE 400)|HMCS ''Bras d'Or'']] in the late 1960s. However, the program was cancelled in the early 1970s due to a shift away from [[anti-submarine warfare]] by the Canadian military. The ''Bras d'Or'' was a surface-piercing type that performed well during her trials, reaching a maximum speed of {{convert|63|kn|km/h}}.

===Soviet Union===
[[File:BTK pr.206M2.jpg|thumb|A Soviet [[Turya-class torpedo boat|Project 206M "Shtorm"]] patrol fast attack craft hydrofoil of the [[Cuban Navy]].]]
The USSR introduced several hydrofoil-based fast attack craft into [[Soviet Navy|their navy]], principally:
* [[Sarancha class missile boat|''Sarancha'' class missile boat]], a unique vessel built in the 1970s
* [[Turya class torpedo boat|''Turya'' class torpedo boat]], introduced in 1972 and still in service
* [[Matka class missile boat|''Matka'' class missile boat]], introduced in the 1980s and still in service
* [[Muravey class patrol boat|''Muravey'' class patrol boat]], introduced in the 1980s and still in service
* [[Project 664-class torpedo boat|Project 664]]

===United States===
[[File:Aerial port beam view of USS Aquila (PHM-4) underway US Navy DN-SC-87-07089.jpg|thumb|[[USS Aquila (PHM-4)|USS ''Aquila'']], a military hydrofoil. The T-shaped foils are visible just below the water.]]
The [[United States Navy|US Navy]] began experiments with hydrofoils in the mid-1950s by funding a sailing vessel that used hydrofoils to reach speeds in the 30 mph range.<ref>[https://books.google.com/books?id=u-EDAAAAMBAJ&pg=PA136 "Sail Boat Stilts Boost Speed."] ''Popular Mechanics'', February 1956, p. 136.</ref> The [[Experimental Craft Hydrofoil No. 4 (XCH-4)|''XCH-4'']] (officially, ''Experimental Craft, Hydrofoil No. 4''), designed by [[William P. Carl]], exceeded speeds of {{convert|65|mph|kn km/h|abbr=on}} and was mistaken for a seaplane due to its shape.<ref>{{cite web|url=http://www.foils.org/index.html|title=XCH4|publisher=International Hydrofoil Society|access-date=8 August 2014|url-status=dead|archive-url=https://web.archive.org/web/20140819151056/http://foils.org/index.html|archive-date=19 August 2014}}</ref> ''Halobates'' was a 1957 US Navy prototype hydrofoil boat built by [[Miami Shipbuilding]].<ref name="auto">{{Cite web|url=https://www.foils.org/wp-content/uploads/2017/09/MIAMI-97-2000-Copy-1.pdf|title=The Rise and Fall of Miami Shipbuilding Corporation, by Robert Johnston, 14 Jul 03}}</ref>

The US Navy implemented a small number of combat hydrofoils, such as the [[Pegasus class hydrofoil|''Pegasus'' class]], from 1977 through 1993. These hydrofoils were fast and well armed.<ref name="JenkinsPegasus">{{cite web |author=George Jenkins | url=http://www.foils.org/phmhist.pdf | title=Patrol Combatant Missile (Hydrofoil): PHM History 1973–1995 | publisher=Foils.org | date=1 November 2000 | archive-url=https://web.archive.org/web/20170817075536/http://www.foils.org/phmhist.pdf | archive-date=2017-08-17 | access-date=2017-08-16 }}</ref>

===Italy===
[[File:Sparviero DN-ST-84-03940.jpg|thumb|right|Italian ''Sparviero'' class hydrofoil-missile NIBBIO P-421.]]
The [[Marina Militare|Italian Navy]] used six hydrofoils of the [[Sparviero class patrol boat|''Sparviero'' class]] starting in the late 1970s. These were armed with a 76 mm gun and two missiles, and were capable of speeds up to {{convert|50|kn|km/h}}. Three similar boats were built for the [[Japan Maritime Self-Defense Force]].

==Sailing and sports==
{{main|Sailing hydrofoil}}
[[File:AC72 New Zealand Aotearoa San Francisco 01.jpg|thumb|[[Team New Zealand]]'s AC72 at the 2013 America's Cup, San Francisco Bay.]]
Several editions of the [[America's Cup]] have been raced with foiling yachts. The 2013 and 2017 editions used the [[AC72]] and [[AC50]] classes of [[catamaran]] respectively, and the 2021 edition used the [[AC75|AC75 class]] of foiling monohulls with canting arms.

The French experimental sail-powered hydrofoil ''[[Hydroptère]]'' is the result of a research project that involves advanced engineering skills and technologies. In September 2009, the ''Hydroptère'' set new sailcraft world speed records in the 500 m category, with a speed of {{convert|51.36|knot|km/h}} and in the {{convert|1|nmi|m|round=0.5|comma=5}} category with a speed of {{convert|50.17|knot|km/h}}.<ref>{{Cite web|url=http://www.sailspeedrecords.com/index.php?option=com_content&view=article&id=104:wssr-newsletter-no-177-hydroptere-world-records-230909&catid=2:news&Itemid=5|title=World Sailing Speed Record Council|website=sailspeedrecords.com}}</ref><ref>{{Cite web|url=http://www.sailspeedrecords.com/index.php?option=com_content&view=article&id=105:wssr-newsletter-no-178-hydroptere-nautical-mile-201109&catid=2:news&Itemid=5|title=World Sailing Speed Record Council|website=sailspeedrecords.com}}</ref>

The 500 m speed record for sailboats is currently held by the ''[[Vestas Sailrocket]]'', an exotic design which operates in effect as a hydrofoil.<ref>{{cite magazine |last1=Fisher |first1=Adam |title=How a Boat-Plane Hybrid Shattered the Sound Barrier of Sailing |url=https://www.wired.com/2013/01/ff-paul-larsen-sailrocket/ |magazine=Wired |access-date=10 May 2021}}</ref>

Another trimaran sailboat is the Windrider Rave.<ref>{{cite web | title=Windrider Wave | author=Windrider | url=http://www.windrider.com/rave.shtml | access-date=7 September 2009 | archive-date=9 May 2007 | archive-url=https://web.archive.org/web/20070509083641/http://windrider.com/rave.shtml | url-status=dead }}</ref> The Rave is a commercially available {{convert|17|ft|m|adj=on}}, two person, hydrofoil trimaran, capable of reaching speeds of {{convert|40|kn|km/h|abbr=on}}. The boat was designed by Jim Brown.

The [[Moth (dinghy)|Moth dinghy]] has evolved into some radical foil configurations.<ref>{{cite news|url=https://www.irishtimes.com/sport/other-sports/gliding-on-top-of-the-water-is-still-sailing-but-not-as-we-know-it-1.1533581|newspaper=The Irish Times|date=September 20, 2013|first=David|last=Branigan|title=Gliding on top of the water is still sailing but not as we know it}}</ref>

[[Hobie Cat|Hobie Sailboats]] produced a production foiling [[trimaran]], the Hobie Trifoiler, the fastest production sailboat. Trifoilers have clocked speeds upward of thirty knots.

A new kayak design, called [[Flyak]], has hydrofoils that lift the kayak enough to significantly reduce drag, allowing speeds of up to {{convert|27|km/h|0|abbr=on}}. Some [[Surfing|surfers]] have developed surfboards with hydrofoils called [[foilboard]]s, specifically aimed at surfing big waves further out to sea.<ref>{{cite web |title= Laird Hamilton: A Surfermag.com exclusive interview |author= Scott Bass |work= [[Surfer (magazine)|Surfer Magazine]] |year= 2009 |url= http://www.surfermag.com/features/onlineexclusives/lairdintrvu/ |access-date=2 December 2010}}
</ref>

Quadrofoil Q2 is a two-seater, four-foiled hydrofoil electrical leisure watercraft. Its initial design was set in 2012 and it has been available commercially since the end of 2016. Powered by a 5.2-kWh lithium-ion battery pack and propelled by a 5.5 kW motor, it reaches the top speed of 40 km/h and has 80 km of range.<ref name="Quadrofoil1">{{cite web |author=Stu Robarts | url=http://newatlas.com/quadrofoil-q2-electric-hydrofoil/46973/?li_source=LI&li_medium=default-widget | title=Electric hydrofoil finally ready to skim the waves | publisher=New Atlas | date=15 December 2016 | archive-url=https://web.archive.org/web/20170817021150/http://newatlas.com/quadrofoil-q2-electric-hydrofoil/46973/?li_source=LI&li_medium=default-widget | archive-date=2017-08-17 | access-date=2017-08-16 }}</ref><ref name="Quadrofoil3">{{cite web |author=Fred Lambert |authorlink=Fred Lambert| url=https://electrek.co/2016/12/22/all-electric-quadrofoil-boat/ | title=All-electric Quadrofoil will soon allow you to fly on water – production is ready, says CEO | work= [[Electrek]] | date=22 December 2016 | archive-url=https://web.archive.org/web/20170817073151/https://electrek.co/2016/12/22/all-electric-quadrofoil-boat/ | archive-date=2017-08-17 | access-date=2017-08-16 }}</ref>

The Manta5 Hydrofoiler XE-1 is a Hydrofoil E-bike, designed and built in [[New Zealand]] that has since been available commercially for pre-order since late 2017.<ref>{{cite web | title= Hydrofoil water bike to launch before Christmas | year= 2017 | url= https://www.stuff.co.nz/business/innovation/90820686/Hydrofoil-water-bike-to-launch-before-Christmas }}</ref> Propelled by a 400 watt motor, it can reach speeds exceeding 14 km/h with a weight of 22 kg. A single charge of the battery lasts an hour for a rider weighing 85 kg.<ref>{{cite web | title = Ride on water: Pre-sale reservations now available for Manta5 hydrofoiling e-bike | year= 2018| url= https://newatlas.com/manta5-hydrofoil-ebike-ride-on-water/55611/ }}</ref>

Candela, a Swedish company, is producing a recreational hydrofoil powerboat, making strong claims for efficiency, performance, and range.<ref>{{cite web |last1=Toll |first1=Micah |title=Watch the world's first electric hydrofoil boat in action |url=https://electrek.co/2020/08/25/worlds-first-electric-hydrofoil-boat-candela-7/ |website=Elektrek |date=25 August 2020 |access-date=10 May 2021}}</ref>

Hydrofoils are now widely used with [[kitesurfing]],<ref>{{cite web|url=https://www.surfertoday.com/kiteboarding/the-bright-and-dark-sides-of-kite-foilboarding|title= The bright and dark sides of kite foilboarding |date=January 28, 2014|work=Surfer Today}}</ref> that is traction kites over water. Hydrofoils are a new trend in [[windsurfing]]<ref>{{cite web|url=https://windfoilzone.com/windfoil-vs-windsurfing/|title=Windfoiling vs Windsurfing – Is Foil is the Future?|first=Romain|last=Jourdan|date=21 January 2021|publisher=Wind Foil Zone|access-date=11 April 2022|archive-date=21 April 2021|archive-url=https://web.archive.org/web/20210421203638/https://windfoilzone.com/windfoil-vs-windsurfing/|url-status=dead}}</ref> - including the new Summer Olympic class, the [[IQFoil]],<ref>{{cite news |last1=Morgan |first1=Liam |title=World Sailing Council approve Starboard iFoil as windsurfing equipment at Paris 2024 |url=https://www.insidethegames.biz/articles/1086570/starboard-ifoil-approved-paris-2024 |accessdate=21 August 2020 |work=[[Inside the Games]] |date=1 November 2019}}</ref> and more recently with [[Wing foiling]], which are essentially a kite with no strings, or a hand-held sail.<ref>{{cite web|url=https://www.ft.com/content/87e259cc-36b0-4583-b3b4-dfea0883eb41 |archive-url=https://ghostarchive.org/archive/20221210/https://www.ft.com/content/87e259cc-36b0-4583-b3b4-dfea0883eb41 |archive-date=10 December 2022 |url-access=subscription|work=Financial Times|title=The only way is up: the irresistible rise of wing foiling|first=Chris|last=Clothier|date=June 18, 2021}}</ref>

[[File:Draagvleugelboot Karla.jpg|thumb|Ukrainian-built [[Voskhod (hydrofoil)|Voskhod]] on the [[noordzeekanaal|North Sea Canal]], the [[Netherlands]]]]
[[File:20091105-TurboJET Urzela.jpg|thumb|[[TurboJET]]'s ''Urzela'' JetFoil on [[West Lamma Channel]], [[Hong Kong]]]]
[[File:20091109-TurboJET Barca.jpg|thumb|[[TurboJET]]'s ''Barca'' Foilcat]]

== Modern passenger boats ==
[[File:MV Flying Poseidon (1982) and Bodrum Lines Kometas at Rhodes with MV Costa Fortuna 11am 5-8-2011.jpg|thumb|''Flying Poseidon'' (built 1982<ref>{{cite web|url=http://www.marinetraffic.com/ais/shipdetails.aspx?MMSI=376308000|archive-url=https://archive.today/20131009030444/http://www.marinetraffic.com/ais/shipdetails.aspx?MMSI=376308000|url-status=dead|archive-date=2013-10-09|title=Flying Poseidon|work=Marinetraffic.com}}</ref>) had just berthed at [[Rhodes]] from [[Fethiye]] when the sister ''Kometas'' hydrofoil<ref>{{cite web|url=http://www.hydrofoils.org/HGal/hgal.htm|title=Russian Hydrofoil Page}}</ref> from [[Bodrum]] also arrived from [[Turkey]] in 2011.]]

Soviet-built [[Voskhod (hydrofoil)|Voskhods]] are one of the most successful passenger hydrofoil designs. Manufactured in Soviet and later Ukrainian Crimea, they are in service in more than 20 countries. The most recent model, [[Voskhod (hydrofoil)|Voskhod-2M FFF]], also known as Eurofoil, was built in [[Feodosiya]] for the Dutch public transport operator [[Connexxion]].<ref>{{cite web|title=Fast Flying Ferry |author=Connexxion |author-link=Connexxion |url=http://www.connexxion.nl/over_water/23/fast_flying_ferry/239 |access-date=9 September 2009 |url-status=dead |archive-url=https://web.archive.org/web/20090823051004/http://www.connexxion.nl/over_water/23/fast_flying_ferry/239/ |archive-date=23 August 2009 }}</ref>

[[File:Type "Kometa 120M" hydrofoil in Sevastopol, Crimea - 2020.jpg|thumb|The first Kometa 120M, named Chaika (Seagull) after [[Valentina Tereshkova]]'s callsign, moored in [[Sevastopol]]]]
Mid-2010s saw a Russian governmental program aimed at restoring passenger hydrofoil production. The {{ill|Kometa 120M|ru|Комета 120М}}, based on the earlier {{ill|Kometa|ru|Комета (теплоход)}}, Kolhida and Katran models, became the first to enter production,<ref>{{cite web |url=https://vm.ru/technology/550718-kometa-vzyala-kurs-na-poluostrov |title=Комета взяла курс на полуостров |trans-title=Kometa has set course for the peninsula |language=Russian |website=vm.ru |publisher=Вечерняя Москва|access-date=August 10, 2021}}</ref> initially on {{ill|Vympel (Rybinsk)|lt=Vympel|ru|Вымпел (судостроительный завод)}} factory in Rybinsk, and later on [[More (Feodosiya)|More]] shipyard in Feodosiya.<ref>{{cite web |url=https://tass.ru/obschestvo/7550113 |title=В Крыму приступили к постройке двух скоростных "Комет" для пассажирских перевозок |trans-title=Production of two high-speed "Komets" has started in Crimea |language=Russian |website=tass.ru |publisher=TASS|access-date=August 10, 2021}}</ref> Since 2018, the ships are running Sevastopol-Yalta and Sochi-Gelenzhik-Novorossiysk, with a Sevastopol-Sochi connection in the immediate plans in 2021.<ref>{{cite web |url=https://www.korabel.ru/news/comments/sochi_i_sevastopol_svyazhut_morskie_passazhirskie_komety.html |title=Сочи и Севастополь свяжут морские пассажирские "Кометы" |trans-title=Sea-going passenger "Komets" will link Sochi and Sevastopol|language=Russian |publisher=korabel.ru |access-date=August 10, 2021}}</ref> At the same time, the [[Alekseyev Central Hydrofoil Design Bureau|Alekseyev Bureau]] began building lighter, smaller {{ill|Valday 45R|ru|Валдай 45Р}} hydrofoils, based on a widely successful {{ill|Polesye (hydrofoil)|lt=Polesye|ru|Полесье_(теплоход)}} model, at its own plant in Nizhny Novgorod,<ref>{{cite web |url=https://www.korabel.ru/news/comments/valday_45r_prevzoshel_ozhidaniya_sozdateley.html |title="Валдай 45Р" превзошел ожидания создателей |trans-title="Valday 45R" has surpassed its creators' expectations |language=Russian |publisher=korabel.ru |access-date=August 10, 2021}}</ref> the relatively shallow-draft boats used on the Ob and the Volga. The {{ill|Meteor 120R|ru|Метеор 120Р}}, a development of the {{ill|Meteor (hydrofoil)|lt=Meteor|ru|Метеор (теплоход)}}, became the Valday's larger sibling, the first ship launched in Nizhny Novgorod in August 2021.<ref>{{cite web |url=http://www.morvesti.ru/news/1679/90897/ |title=Первый "Метеор 120Р" нового поколения спустили на воду в Нижегородской области |trans-title=The first new-generation «Meteor 120R» has been launched in Nizhny Novgorod oblast |language=Russian |website=morvesti.ru |publisher=Морские вести России |access-date=August 10, 2021}}</ref>

The [[Boeing 929]] is widely used in [[Asia]] for passenger services, between [[Hong Kong]] and [[Macau]] and between the many islands of [[Japan]]. It was also used between [[Kyushu]] of Japan and [[Korean peninsula]]. Hong Kong ferry company [[TurboJET]] was the main user of Boeing 929.

=== Current operation ===
{{More citations needed section|date=September 2022}}
Current operators of hydrofoils include:

* [[TurboJET]] service, which speeds passengers across the [[Pearl River Delta]] between [[Hong Kong–Macau Ferry Terminal|Hong Kong]] and [[Outer Harbour Ferry Terminal|Macau]] in less than an hour, with an average speed of {{convert|45|kn|km/h}}, mainly using [[Boeing]]'s [[Boeing Jetfoil|Jetfoil]], until suspension of service due to [[COVID-19 pandemic]]. After service resumption in 2023, only one Jetfoil and one [[Foilcat]] re-entered into service. Also serviced [[Fuyong Ferry Terminal|Shenzhen]], [[Nansha Ferry Port|Panyu (Nansha)]] and [[China Ferry Terminal|Kowloon]]. Operated by Shun Tak-China Travel Ship Management Limited.
* [[Voskhod (hydrofoil)|Voskhod]] and ''Polesye'' service between [[Tulcea]] and [[Sulina]] on the [[Danube]].
* ''Meteor'' and ''Polesye'' service in [[Poland]] between [[Szczecin]] and [[Świnoujście]].
* ''Cometa'' service between [[Nizhneangarsk]] and [[Irkutsk]] on [[Lake Baikal]].
* ''Cometa'' service between [[Vladivostok]] and [[Slavyanka, Primorsky Krai|Slavyanka]].
* ''Polesye'' service between [[Mozyr]] and [[Turaŭ|Turov]] on the [[Pripyat River]] ([[Belarus]]).
* ''Meteor'' service between [[Saint Petersburg]], [[Russia]] and the [[Peterhof Palace]], a summer palace of Russian tsars.

[[File:Lake Ladoga. Valaam. Meteor hydrofoil P7170383 2200.jpg|thumb|Hydrofoil high-speed boat Meteor on [[Lake Ladoga]], [[Russia]].]]
[[File:Hydrofoil near Piraeus.JPG|thumb|Passenger hydrofoil ''Flying Dolphin Zeus'' moving at high speed near [[Piraeus]], [[Greece]].]]

* ''Meteor'' service between [[Saint Petersburg]], [[Russia]] and the [[Kronstadt]], a strongly fortified Russian seaport town, located on Kotlin Island, near the head of the Gulf of Finland. It lies thirty kilometers west of Saint Petersburg. Since 2012 replaced by a catamaran ''Mercury''.
* ''Meteor'', ''Raketa'' and ''Voskhod'' hydrofoil types operate all over [[Volga]], [[Don River (Russia)|Don]] and [[Kama River]]s in [[Russia]]. Also the [[Lena River]] and [[Amur River]].
* ''Meteor'' hydrofoils are operated by a number of tour operators in [[Croatia]], mostly for packaged tours, but there are also some scheduled services to islands in Adriatic.
* '''In Italy hydrofoils have been used for commercial connections since 1956''', by the Rodriguez shipyards and the [[SNAV]] company. Currently (2025), the main hydrofoil operator in Italy is Liberty Lines,<ref>[https://www.libertylines.it/compagnia/la-nostra-flotta/]</ref> which operates connections between the smaller Sicilian islands ([[Aeolian Islands|Aeolian Island]], [[Aegadian Islands|Aegadian Island]], [[Pelagie Islands]], [[Ustica]] and [[Pantelleria]]) with [[Sicily]] and [[Calabria]], through the [[Strait of Messina]] (between [[Messina]] and [[Reggio Calabria]]) and between [[Trieste]] and [[Mali Lošinj]] ([[Croatia|Croazia]]). SNAV operates connections between [[Naples]] and the smaller campanian islands and - in the summer period - between Naples and the Aeolian Islands.<ref name=":0">{{Cite web |last=admin |date=2021-11-23 |title=Super Jumbo |url=https://www.snav.it/en/super-jumbo-2/ |access-date=2025-06-11 |website=Snav |language=en-US}}</ref> Hydrofoils are regularly operated on the three major Italian lakes by branches of the [[Ministry of Infrastructure and Transport (Italy)|Ministry of Infrastructure and Transport]]: ''[[Navigazione Lago Maggiore]]'' services routes on [[Lake Maggiore]] between [[Locarno]] and [[Arona, Piedmont|Arona]], ''[[Navigazione Lago di Como]]'' services routes on [[Lake Como]], and ''[[Navigazione Lago di Garda]]'' services routes on [[Lake Garda]]. Three units of the Rodriguez RHS150 type operate on each lake, for a total of nine hydrofoils. At least until 2024, former Russian hydrofoils was used in southern Italy for connection with islands of [[Lazio]] and [[Campania]] by VETORaliscafi.<ref>{{Cite web |title=Benvenuti in Vetor Aliscafi |url=http://www.vetor.it/company.htm |access-date=2025-06-11 |website=www.vetor.it}}</ref> SNAV had five RHS200, RHS160 and RHS150 used in the connections between [[Naples]] and the islands of [[Capri]] and [[Ischia]], now mainly replaced by catamarans (the only hydrofoil left in the SNAV fleet, the RHS200 Super Jumbo, connect Naples and the Aeolian Islands in summer).<ref name=":0" />
* A regular hydrofoil service runs from [[Istanbul]] to [[Yalova]].
* [[Hellenic Seaways]] operate their Flying Dolphins service over many routes in the [[Aegean Sea|Aegean]], between the [[Cyclades]], [[Saronic Gulf]] islands such as Aegina and Poros, and [[Athens]].
* ''Meteor'' (2), ''Polesye'' (4) and ''Voskhod'' (3) hydrofoil types operate in [[Hungary]]. MAHART PassNave Ltd. operates scheduled hydrofoil liners between [[Budapest]], [[Bratislava]] and [[Vienna]], inland liners between Budapest and the [[Danube Bend]], and theme cruises to Komárom, Solt, Kalocsa and Mohács.
* "Kometa" Flying Dolphin services are currently operated by Joy Cruises between [[Corfu]] and [[Paxos (island)|Paxos]]. They run from [[Corfu (city)|Corfu Port]] to [[Gaios]] using two hydrofoils: ''Ilida'' and ''Ilida II''. The company operates also an international service from Corfu to Saranda (Albania) using the hydrofoil ''Ilida Dolphin'' of the same type.
* "Kometa" type hydrofoils (registered in Albania) are operated by Ionian Cruises and Finikas Lines between Saranda and Corfu.
* Russian hydrofoils of the ''Kometa'' type operated on the [[Bulgarian Black Sea Coast]] connecting [[Varna, Bulgaria|Varna]], [[Nesebar]], [[Burgas]], [[Sozopol]], [[Primorsko]], and [[Tsarevo]], and ''Raketa'' and ''Meteor'' models served the Bulgarian [[Danube]] ports between [[Rousse]] and [[Vidin]]. Both services were discontinued in the 1990s. In 2011 the service reopened between Varna, Nesebar, Burgas and Sozopol, operated by Bulgarian Hydrofoils Ltd.
* Vietnamese ''Greenline Company'' operates hourly shuttle service between [[Ho Chi Minh City]], [[Vung Tau]] and [[Con Dao]] island. Hydrofoil lines using the Russian-built Meteor type also connect [[Hai Phong]], [[Ha Long]] and [[Mong Cai]] in North Vietnam, [[Phan Thiet]] and [[Phu Quy Island]] and between [[Rach Gia]] and [[Phu Quoc Island]] in the South.
*The service between [[Busan]], [[South Korea]] and [[Fukuoka, Fukuoka|Fukuoka]], [[Japan]] is operated by two companies. Japanese [[:ja:JR九州高速船|JR Kyūshū Jet Ferry]] operates ''[[Beetle (JR Kyushu)|Beetle]]'' five times a day. Korean [[Miraejet]] operates ''[[Kobee]]'' three to four times a day. All of their fleets are [[Boeing Jetfoil|Boeing 929]].
*As of February 2008, all of the commercial lines in Japan use [[Boeing Jetfoil|Boeing 929]]. The routes include:
**[[:ja:佐渡汽船|Sado Kisen]] operates the route between [[Sado, Niigata|Sado]] and [[Niigata, Niigata|Niigata]].
**[[Tōkai Kisen]] operates ''Seven Islands'', running between [[Tokyo]] and [[Izu Islands]], via [[Tateyama, Chiba|Tateyama]] or [[Yokosuka, Kanagawa|Yokosuka]]. The destinations include [[Izu Ōshima]], [[Toshima Island|Toshima]], [[Niijima]], [[Shikinejima]], and [[Kozushima|Kōzushima]]. The same ship also links [[Atami, Shizuoka|Atami]] and Izu Ōshima.
**[[:ja:九州郵船|Kyūshū Yūsen]] operates the route between [[Fukuoka, Fukuoka|Fukuoka]], [[Iki Island|Iki]], and the two ports of [[Tsushima Island|Tsushima]].
**[[:ja:九州商船|Kyūshū Shōsen]] operates the route between [[Nagasaki, Nagasaki|Nagasaki]] and the two of [[Gotō Islands]], namely [[:ja:福江島|Fukuejima]] and [[Nakadorijima|Nakadōrijima]].
**[[:ja:鹿児島商船|Kagoshima Shōsen]] and [[:ja:コスモライン (鹿児島県)|Cosmo Line]] operate the various routes between [[Kagoshima, Kagoshima|Kagoshima]] and [[Tanegashima]] or [[Yakushima]].
* In 2012, Agriculture, Fisheries and Conservation Department (AFCD) in [[Hong Kong]] leased a 12-meter HAWC (Hydrofoil Assisted Water Craft), a [[catamaran]], to patrol the [[Hong Kong UNESCO Global Geopark]] in the [[Sai Kung District|Sai Kung]] Volcanic Rock Region.
* In 2017, [[Voskhod (hydrofoil)|Voskhod]] boat began operating on 2 lines in [[Ukraine]]: [[Nova Kakhovka]]-[[Kherson]]-[[Hola Prystan]], [[Mykolaiv]]-[[Kinburn Spit]], [[Ochakiv]]-[[Kinburn Spit]].<ref>[https://dnepr.news/news/dnepr-otnyne-mozhno-preodolet-na-rakete Днепр отныне можно преодолеть на ракете]. - dnepr.news</ref>
* In July 2018, the new generation [[Kometa 120M]] boat has started operation on the busy [[Sevastopol]]-[[Yalta]] route in [[Crimea]], with the plans to add two more and possible other routes in 2019.

=== Discontinued operations ===
* Until 31 December 2013, Fast Flying Ferries operated by [[Connexxion]] provided a regular [[public transport]] service over the [[North Sea Canal]] between [[Amsterdam Centraal|Amsterdam Central Station]] and [[Velsen|Velsen-Zuid]] in the [[Netherlands]], using [[Voskhod (hydrofoil)|Voskhod]] 2M hydrofoils. It was stopped due to a new [[speed limit]].<ref>{{cite web |title=Fast Flying Ferry ends in 2014 |url=http://water.connexxion.nl/diensten/602/fast-flying-ferry-stopt-in-2014/2728 |website=[[Connexxion]] |language=Dutch |date=1 March 2013 |access-date=2 July 2013 |archive-url=https://web.archive.org/web/20130721083912/http://water.connexxion.nl/diensten/602/fast-flying-ferry-stopt-in-2014/2728 |archive-date=21 July 2013 |url-status=dead |df=dmy-all }}</ref>
* Between 1981 and 1990, [[Transmediterranea]] operated a service of hydrofoils connecting [[Ceuta]] and [[Algeciras]] in the Strait of Gibraltar. The crossing took half an hour, in comparison to the hour and a half of conventional ferries. Due to the common extreme winds and storms that take place in winter in the Strait of Gibraltar, the service was replaced in 1990 by catamarans, which were also able to carry cars. At the peak of the year, in summer, there was a service every half an hour in each direction. This high-speed connection had a big impact on the development of Ceuta, facilitating one-day business trips to mainland Spain.
* Between 1964 and 1991 the [[Sydney hydrofoils]] operated on [[Port Jackson|Sydney Harbour]] between [[Circular Quay]] and [[Manly, New South Wales|Manly]].
* Between 1969 and 1998 [[Red Funnel]] operated between [[Southampton]] and [[Cowes|Cowes, Isle of Wight]].<ref>{{Cite web|title=Red Funnel Hydrofoil Passenger Ferry|url=https://www.wightpedia.org.uk/detail2.php?id=red-funnel-hydrofoil-passenger-ferry|access-date=2021-02-05}}</ref>
* During the 1970s and 1980s there were frequent services between [[Belgrade]] and [[Tekija (Kladovo)|Tekija]] in [[Iron Gates|Đerdap gorge]]. The distance of {{convert|220|km|nmi mi|abbr=on}} was covered in 3 hours and 30 minutes downstream and 4 hours upstream.<ref>{{cite web | title=Beogradske priče: Gliserima do Đerdapa| author=Večernje novosti| author-link=Večernje novosti| url=http://www.novosti.rs/vesti/beograd.74.html:575041-Beogradske-price-Gliserima-do-Djerdapa | access-date=6 November 2015}}</ref>
* Between 1980 and 1981, [[British and Irish Steam Packet Company|B+I Line]] operated a [[Boeing 929]] jetfoil, named ''Cú Na Mara'' (Hound of the Sea), between Liverpool and Dublin. The service was not successful and was discontinued at the end of the 1981 season.<ref>{{Cite web|url=http://www.irishships.com/a_history_of_roll_on.htm|title=A History of Roll on|date=2006-03-19|website=archive.ph|access-date=2019-11-04|archive-date=19 March 2006|archive-url=https://archive.today/20060319220350/http://www.irishships.com/a_history_of_roll_on.htm|url-status=dead}}</ref>
* Between the 1960s and 1985 there were hydrofoils going between Malmö, Sweden and Copenhagen, Denmark. They were retired and exchanged for catamarans. The service got cancelled when the Öresund Bridge got built in the early 2000s.
* [[Condor Ferries]] operated six hydrofoil ferries over a 29-year period between the [[Channel Islands]], the south coast of England and [[Saint-Malo]] in France.
* Following the restoration of [[Estonia]]n independence in the 1990s, the regular ferry service between [[Helsinki]] and [[Tallinn]] was augmented by Soviet built hydrofoils during the summer season in periods of good weather. The higher speed service competed with the traditional [[Roll-on/roll-off|ro-ro ferries]] but allowed easy day trips for pedestrian travellers. They were ultimately replaced with high-speed catamarans that could also carry vehicles and have better seaworthiness; however, the latter ceased operations as the operator filed for bankruptcy in May 2018.<ref>{{Cite web|url=https://news.err.ee/834522/linda-line-declared-bankrupt-by-court|title=Linda Line declared bankrupt by court|date=25 May 2018|website=ERR}}</ref>

== See also ==
{{Div col |colwidth=26em}}
* [[Boeing hydrofoils]]
* ''[[Disco Volante (ship)|Disco Volante]]''
* [[Flyak]] – a hydrofoil kayak
* [[Foilboard]]
* ''[[The Hydrofoil Mystery]]'' – historical fiction
* [[Hydroplane (boat)|Hydroplane]], a different application of lift to the hull itself
* [[Planing (sailing)]]
* ''[[Raketa (hydrofoil)|Raketa]]''
* [[Riverboat]]
* [[Sailing hydrofoil]]
* [[Sit-down hydrofoil]]
* [[Supercavitation]]
* [[Trampofoil]] – a one-person human-powered hydrofoil
* ''[[Voskhod (hydrofoil)|Voskhod]]''
* [[LISA Akoya]] – amphibious plane with hydrofoil assisted takeoff
{{Div col end}}

==References==
{{Reflist|30em}}

==External links==
{{wiktionary|hydrofoil}}
{{commons category|Hydrofoils}}
* [http://foils.org The International Hydrofoil Society]
* [http://www.hysucraft.com Fast CC Hydrofoil design by Prof. KG Hoppe, inventor of HYSUCAT technology patented by University of Stellenbosch, S.A.]
* [https://hyfoilmarine.com/ HYFOIL Marine has cooperative technology agreements with Prof. KG Hoppe]
* [http://www.hawctech.com Hydrofoil Assisted Water Craft employing HYSUCAT and HYSUWAC patents in their projects and vessels currently in operation]
* [http://www.hydrofoils.ch Swiss experimental hydrofoils]
* [https://web.archive.org/web/20100605014428/http://hyraii.ethz.ch/ HyRaii - Hydrofoil Sailboat, Student Project ETH Zurich]

{{Public transport|state=collapsed}}

{{Authority control}}

[[Category:Hydrofoils|*]]
[[Category:Nautical terminology]]
[[Category:English inventions]]
[[Category:Vehicles introduced in 1906]]

Absolute zero

2025-07-24T18:20:28Z

45.232.105.68:

{{short description|Lowest theoretical temperature}}
{{About|the minimum temperature limit|other uses|Absolute Zero (disambiguation)}}
{{Use dmy dates|date=May 2025}}
{{More citations needed|date=December 2022}}
[[File:CelsiusKelvin.svg|thumb|upright=0.5|Zero [[kelvin]] (−273.15 °C) is defined as absolute zero.]]
'''Absolute zero''' is the lowest possible [[temperature]], a state at which a system's [[internal energy]], and in ideal cases [[entropy]], reach their minimum values. The [[Kelvin scale]] is defined so that absolute zero is 0 K, equivalent to −273.15 °C on the [[Celsius|Celsius scale]],<ref name="sib2115">{{Cite web |title=SI Brochure: The International System of Units (SI) – 9th edition (updated in 2022) |url=https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-EN.pdf/2d2b50bf-f2b4-9661-f402-5f9d66e4b507 |access-date=7 September 2022 |publisher=BIPM |page=133 |quote=[...], it remains common practice to express a thermodynamic temperature, symbol T, in terms of its difference from the reference temperature T0 = 273.15 K, close to the ice point. This difference is called the Celsius temperature.}}</ref><ref name="arora">{{Cite book |last=Arora |first=C. P. |url=https://books.google.com/books?id=w8GhW3J8RHIC&pg=PA43 |title=Thermodynamics |publisher=Tata McGraw-Hill |year=2001 |isbn=978-0-07-462014-4 |at=Table 2.4 page 43}}</ref> and −459.67 °F on the [[Fahrenheit scale]].<ref>{{Cite web |last=Zielinski |first=Sarah |date=1 January 2008 |title=Absolute Zero |url=http://www.smithsonianmag.com/science-nature/absolute-zero-200801.html |url-status=dead |archive-url=https://web.archive.org/web/20130401180715/http://www.smithsonianmag.com/science-nature/absolute-zero-200801.html |archive-date=1 April 2013 |access-date=26 January 2012 |publisher=Smithsonian Institution}}</ref> The Kelvin and [[Rankine scale|Rankine]] temperature scales set their zero points at absolute zero by design. This limit can be estimated by extrapolating the [[ideal gas law]] to the temperature at which the volume or pressure of a classical gas becomes zero.

At absolute zero, there is no [[thermal motion]]. However, due to [[quantum mechanics|quantum effects]], the particles still exhibit minimal motion mandated by the [[Uncertainty principle|Heisenberg uncertainty principle]] and, for a system of fermions, the [[Pauli exclusion principle]]. Even if absolute zero could be achieved, this residual quantum motion would persist.

Although absolute zero can be approached, it cannot be reached. Some [[isentropic process]]es, such as [[adiabatic expansion]], can lower the system's temperature without relying on a colder medium. Nevertheless, the [[third law of thermodynamics]] implies that no physical process can reach absolute zero in a finite number of steps. As a system nears this limit, further reductions in temperature become increasingly difficult, regardless of the cooling method used. In the 21st century, scientists have achieved temperatures below 100 picokelvin (pK). At low temperatures, matter displays exotic quantum phenomena such as [[superconductivity]], [[superfluidity]], and [[Bose–Einstein condensation]].

== Ideal gas laws ==
[[File:Gas_thermometer_and_absolute_zero.svg|thumb|Pressure–temperature plots for three different gas samples, measured at constant volume, all extrapolate to zero at the same point, the absolute zero.]]
For an [[ideal gas]], the pressure at constant volume decreases linearly with temperature, and the volume at constant pressure also decreases linearly with temperature. When these relationships are expressed using the Celsius scale, both pressure and volume extrapolate to zero at approximately −273.15 °C. This implies the existence of a lower bound on temperature, beyond which the gas would have negative pressure or volume—an unphysical result.{{Cn|date=June 2025}}

To resolve this, the concept of absolute temperature is introduced, with 0 kelvins defined as the point at which pressure or volume would vanish in an ideal gas. This temperature corresponds to −273.15 °C, and is referred to as absolute zero. The ideal gas law is therefore formulated in terms of absolute temperature to remain consistent with observed gas behavior and physical limits.{{Cn|date=June 2025}}

==Absolute temperature scales==
[[Absolute temperature]] is conventionally measured in [[kelvin|Kelvin scale]] (using [[Celsius]]-scaled increments)<ref name="sib2115" /> and, more rarely, in [[Rankine scale]] (using [[Fahrenheit]]-scaled increments). Absolute temperature measurement is uniquely determined by a multiplicative constant which specifies the size of the ''degree'', so the ''ratios'' of two absolute temperatures, ''T''2/''T''1, are the same in all scales.

Absolute temperature also emerges naturally in [[statistical mechanics]]. In the [[Maxwell–Boltzmann statistics|Maxwell–Boltzmann]], [[Fermi–Dirac statistics|Fermi–Dirac]], and [[Bose–Einstein statistics|Bose–Einstein]] distributions, absolute temperature appears in the exponential factor that determines how particles populate energy states. Specifically, the relative number of particles at a given energy ''E'' depends exponentially on ''E/kT'', where ''k'' is the [[Boltzmann constant]] and ''T'' is the absolute temperature.{{cn|date=September 2023}}

== Unattainability of absolute zero ==
[[Image:Can T=0 be reached.jpg|thumb|Left side: Absolute zero could be reached in a finite number of steps if {{math|1=''S''(0, ''X''1) ≠ ''S''(0, ''X''2)}}. Right: An infinite number of steps is needed since {{math|1=''S''(0, ''X''1) = ''S''(0, ''X''2)}}. Here, {{math|1=''X''}} is some controllable parameter of the system, such as its volume or pressure.]]
The [[third law of thermodynamics]] concerns the behavior of [[entropy]] as temperature approaches absolute zero. It states that the entropy of a system approaches a constant minimum at 0 K. For a perfect crystal, this minimum is taken to be zero, since the system would be in a state of perfect order with only one [[Microstate (statistical mechanics)|microstate]] available. In some systems, there may be more than one microstate at minimum energy and there is some residual entropy at 0 K.<ref name="b288">{{cite book | last=Blundell | first=Stephen J. | last2=Blundell | first2=Katherine M. | title=Concepts in Thermal Physics | publisher=Oxford university press | publication-place=Oxford | date=2010 | isbn=978-0-19-956209-1 | pages=193-198}}</ref>

Several other formulations of the third law exist. [[Nernst heat theorem]] holds that the change in entropy for any constant-temperature process tends to zero as the temperature approaches zero.<ref name="f802">{{cite book |last=Atkins |first=Peter William |title=Atkins' Physical Chemistry |last2=Paula |first2=Julio De |last3=Keeler |first3=James |date=2018 |publisher=Oxford University Press |isbn=978-0-19-876986-6 |edition=11th |publication-place=Oxford, United Kingdom ; New York, NY |page= |pages=93–96}}</ref> A key consequence is that absolute zero cannot be reached, since removing heat becomes increasingly inefficient and entropy changes vanish. This unattainability principle means no physical process can cool a system to absolute zero in a finite number of steps or finite time.<ref name="q183">{{cite book |last=Shell |first=M. Scott |title=Thermodynamics and Statistical Mechanics |date=2015-04-16 |publisher=Cambridge University Press |isbn=978-1-107-01453-4 |publication-place=Cambridge |page= |pages=312–315}}</ref>

== Thermal properties at low temperatures ==
Using the [[Debye model]], the [[specific heat capacity|specific heat]] and entropy of a pure crystal are proportional to ''T'' 3, while the [[enthalpy]] and [[chemical potential]] are proportional to ''T'' 4 (Guggenheim, p. 111). These quantities drop toward their ''T'' = 0 limiting values and approach with ''zero'' slopes. For the specific heats at least, the limiting value itself is definitely zero, as borne out by experiments to below 10 K. Even the less detailed [[Einstein solid|Einstein model]] shows this curious drop in specific heats. In fact, all specific heats vanish at absolute zero, not just those of crystals. Likewise for the coefficient of [[thermal expansion]]. [[Maxwell relations|Maxwell's relations]] show that various other quantities also vanish. These phenomena were unanticipated.

One model that estimates the properties of an [[electron]] gas at absolute zero in metals is the [[Fermi gas]]. The electrons, being [[fermion]]s, must be in different quantum states, which leads the electrons to get very high typical [[velocities]], even at absolute zero. The maximum energy that electrons can have at absolute zero is called the [[Fermi energy]]. The Fermi temperature is defined as this maximum energy divided by the Boltzmann constant, and is on the order of 80,000 K for typical electron densities found in metals. For temperatures significantly below the Fermi temperature, the electrons behave in almost the same way as at absolute zero. This explains the failure of the classical [[equipartition theorem]] for metals that eluded classical physicists in the late 19th century.

=== Gibbs free energy ===
Since the relation between changes in [[Gibbs free energy]] (''G''), the enthalpy (''H'') and the entropy is
:<math> \Delta G = \Delta H - T \Delta S \,</math>

thus, as ''T'' decreases, Δ''G'' and Δ''H'' approach each other (so long as Δ''S'' is bounded). Experimentally, it is found that all spontaneous processes (including [[chemical reaction]]s) result in a decrease in ''G'' as they proceed toward [[thermodynamic equilibrium|equilibrium]]. If Δ''S'' and/or ''T'' are small, the condition Δ''G'' < 0 may imply that Δ''H'' < 0, which would indicate an [[exothermic]] reaction. However, this is not required; [[endothermic]] reactions can proceed spontaneously if the ''T''Δ''S'' term is large enough.

Moreover, the slopes of the [[derivative]]s of Δ''G'' and Δ''H'' converge and are equal to zero at ''T'' = 0. This ensures that Δ''G'' and Δ''H'' are nearly the same over a considerable range of temperatures and justifies the approximate [[empiricism|empirical]] Principle of Thomsen and Berthelot, which states that ''the equilibrium state to which a system proceeds is the one that evolves the greatest amount of heat'', i.e., an actual process is the ''most exothermic one'' (Callen, pp. 186–187).

==Zero-point energy==
{{Main article|Zero-point energy}}
[[File:Oscillator zero-point energy.svg|thumb|Probability densities and energies (indicated by an offset) of the four lowest energy eigenstates of a [[quantum harmonic oscillator]]. ZPE denotes the zero-point energy.]]
Even at absolute zero, a quantum system retains a minimum amount of energy due to the [[Heisenberg uncertainty principle]], which prevents particles from having both perfectly defined position and momentum. This residual energy is known as [[zero-point energy]]. In the case of the [[quantum harmonic oscillator]], a standard model for vibrations in atoms and molecules, the uncertainty in a particle's momentum implies it must retain some [[kinetic energy]], while the uncertainty in its position contributes to [[potential energy]]. As a result, such a system has a nonzero energy at absolute zero.<ref name="c473"/>

Zero-point energy helps explain certain physical phenomena. For example, [[liquid helium]] does not solidify at normal pressure, even at temperatures near absolute zero. The large zero-point motion of helium atoms, caused by their low mass and weak interatomic forces, prevents them from settling into a solid structure. Only under high pressure does helium solidify, as the atoms are forced closer together and the interatomic forces grow stronger.<ref name="c473">{{cite book | last=Townsend | first=John | title=A Modern Approach to Quantum Mechanics | publisher=University Science Books | publication-place=Mill Valley, Calif | date=2012-07-19 | isbn=978-1-891389-78-8 | pages=257-259}}</ref>

==History==
[[File:Robert Boyle 0001.jpg|thumb|upright=1.05|[[Robert Boyle]] pioneered the idea of an absolute zero.]]
One of the first to discuss the possibility of an absolute minimal temperature was [[Robert Boyle]]. His 1665 ''New Experiments and Observations touching Cold'', articulated the dispute known as the ''primum frigidum''.<ref>{{Cite book |last=Stanford |first=John Frederick |author-link=John Frederick Stanford |url=https://books.google.com/books?id=8vRaAAAAMAAJ&pg=PA651 |title=The Stanford Dictionary of Anglicised Words and Phrases |year=1892}}</ref> The concept was well known among naturalists of the time. Some contended an absolute minimum temperature occurred within earth (as one of the four [[classical element]]s), others within water, others air, and some more recently within [[nitre]]. But all of them seemed to agree that, "There is some body or other that is of its own nature supremely cold and by participation of which all other bodies obtain that quality."<ref>{{Cite book |last=Boyle |first=Robert |title=New Experiments and Observations touching Cold |year=1665}}</ref>

===Limit to the "degree of cold"===
The question of whether there is a limit to the degree of coldness possible, and, if so, where the zero must be placed, was first addressed by the French physicist [[Guillaume Amontons]] in 1703, in connection with his improvements in the [[gas thermometer|air thermometer]]. His instrument indicated temperatures by the height at which a certain mass of air sustained a column of mercury—the pressure, or "spring" of the air varying with temperature. Amontons therefore argued that the zero of his thermometer would be that temperature at which the spring of the air was reduced to nothing.<ref>{{Cite journal |last=Amontons |date=18 April 1703 |title=Le thermomètre rèduit à une mesure fixe & certaine, & le moyen d'y rapporter les observations faites avec les anciens Thermométres |trans-title=The thermometer reduced to a fixed & certain measurement, & the means of relating to it observations made with old thermometers |url=https://www.biodiversitylibrary.org/item/87349#page/216/mode/1up |journal=Histoire de l'Académie Royale des Sciences, avec les Mémoires de Mathématique et de Physique pour la même Année |language=French |pages=50–56}} Amontons described the relation between his new thermometer (which was based on the expansion and contraction of alcohol (''esprit de vin'')) and the old thermometer (which was based on air). From p. 52: ''" […] d'où il paroît que l'extrême froid de ce Thermométre seroit celui qui réduiroit l'air à ne soutenir aucune charge par son ressort, […] "'' ([…] whence it appears that the extreme cold of this [air] thermometer would be that which would reduce the air to supporting no load by its spring, […]) In other words, the lowest temperature which can be measured by a thermometer which is based on the expansion and contraction of air is that temperature at which the air's pressure ("spring") has decreased to zero.</ref> He used a scale that marked the boiling point of water at +73 and the melting point of ice at +{{frac|51|1|2}}, so that the zero was equivalent to about −240 on the Celsius scale.<ref name="AS2016">{{Cite EB1911|wstitle=Cold}}</ref> Amontons held that the absolute zero cannot be reached, so never attempted to compute it explicitly.<ref>{{Cite journal |last=Talbot |first=G. R. |last2=Pacey |first2=A. C. |date=1972 |title=Antecedents of thermodynamics in the work of Guillaume Amontons |journal=Centaurus |volume=16 |issue=1 |pages=20–40 |bibcode=1972Cent...16...20T |doi=10.1111/j.1600-0498.1972.tb00163.x}}</ref> The value of −240 °C, or "431 divisions [in Fahrenheit's thermometer] below the cold of freezing water"<ref>{{Cite book |last=Martine |first=George |title=Essays Medical and Philosophical |date=1740 |publisher=A. Millar |location=London, England, UK |page=291 |chapter=Essay VI: The various degrees of heat in bodies |chapter-url=https://books.google.com/books?id=tSm2Ws6bg0oC&pg=PA291}}</ref> was published by [[George Martine (physician)|George Martine]] in 1740.

This close approximation to the modern value of −273.15 °C<ref name="sib2115"/> for the zero of the air thermometer was further improved upon in 1779 by [[Johann Heinrich Lambert]], who observed that {{convert|-270|C|F K}} might be regarded as absolute cold.<ref>{{Cite book |last=Lambert |first=Johann Heinrich |title=Pyrometrie |year=1779 |location=Berlin, Germany |oclc=165756016}}</ref>

Values of this order for the absolute zero were not, however, universally accepted about this period. [[Pierre-Simon Laplace]] and [[Antoine Lavoisier]], in their 1780 treatise on heat, arrived at values ranging from 1,500 to 3,000 below the freezing point of water, and thought that in any case it must be at least 600 below. [[John Dalton]] in his ''Chemical Philosophy'' gave ten calculations of this value, and finally adopted −3,000 °C as the natural zero of temperature.

===Charles's law===
From 1787 to 1802, it was determined by [[Jacques Charles]] (unpublished), [[John Dalton]],<ref>J. Dalton (1802), [https://books.google.com/books?id=3qdJAAAAYAAJ&pg=PA595 "Essay II. On the force of steam or vapour from water and various other liquids, both in vacuum and in air" and Essay IV. "On the expansion of elastic fluids by heat" ], ''Memoirs of the Literary and Philosophical Society of Manchester'', vol. 8, pt. 2, pp. 550–574, 595–602.</ref> and [[Joseph Louis Gay-Lussac]]<ref>{{Citation |last=Gay-Lussac, J. L. |title=Recherches sur la dilatation des gaz et des vapeurs |work=Annales de Chimie |volume=XLIII |page=137 |year=1802 |author-link=Joseph Louis Gay-Lussac}}. [http://web.lemoyne.edu/~giunta/gaygas.html English translation (extract).]</ref> that, at constant pressure, ideal gases expanded or contracted their volume linearly ([[Charles's law]]) by about 1/273 parts per degree Celsius of temperature's change up or down, between 0° and 100° C. This suggested that the volume of a gas cooled at about −273 °C would reach zero.

===Lord Kelvin's work===
After [[James Prescott Joule]] had determined the mechanical equivalent of heat, [[William Thomson, 1st Baron Kelvin|Lord Kelvin]] approached the question from an entirely different point of view, and in 1848 devised a scale of absolute temperature that was independent of the properties of any particular substance and was based on [[Nicolas Léonard Sadi Carnot|Carnot]]'s theory of the Motive Power of Heat and data published by [[Henri Victor Regnault]].<ref>{{Cite journal |last=Thomson |first=William |author-link=Lord Kelvin |date=1848 |title=On an Absolute Thermometric Scale founded on Carnot's Theory of the Motive Power of Heat, and calculated from Regnault's observations. |url=https://www.biodiversitylibrary.org/item/87114#page/72/mode/2up |journal=Proceedings of the Cambridge Philosophical Society |volume=1 |pages=66–71}}</ref> It followed from the principles on which this scale was constructed that its zero was placed at −273 °C, at almost precisely the same point as the zero of the air thermometer,<ref name="AS2016" /> where the air volume would reach "nothing". This value was not immediately accepted; values ranging from {{convert|-271.1|C}} to {{convert|-274.5|C}}, derived from laboratory measurements and observations of [[Atmospheric refraction#Astronomical refraction|astronomical refraction]], remained in use in the early 20th century.<ref>{{Citation |last=Newcomb |first=Simon |title=A Compendium of Spherical Astronomy |date=1906 |page=175 |place=New York |publisher=The Macmillan Company |oclc=64423127 |author-link=Simon Newcomb}}.</ref>

===The race to absolute zero===
{{see also|Timeline of low-temperature technology}}
[[File:Leiden - Kamerlingh Onnes Building - Commemorative plaque.jpg|thumb|upright=1.2|Commemorative plaque in Leiden]]
With a better theoretical understanding of absolute zero, scientists were eager to reach this temperature in the lab.<ref name="MyUser_YouTube_November_23_2016c">{{Cite web |title=ABSOLUTE ZERO – PBS NOVA DOCUMENTARY (full length) |url=https://www.youtube.com/watch?v=mTFRgosx4aQ&t=894s |url-status=dead |archive-url=https://web.archive.org/web/20170406015107/https://www.youtube.com/watch?v=mTFRgosx4aQ |archive-date=6 April 2017 |access-date=23 November 2016 |newspaper=YouTube}}</ref> By 1845, [[Michael Faraday]] had managed to liquefy most gases then known to exist, and reached a new record for lowest temperatures by reaching {{convert|-130|C|F K}}. Faraday believed that certain gases, such as oxygen, nitrogen, and [[hydrogen]], were permanent gases and could not be liquefied.<ref>[http://www.scienceclarified.com/Co-Di/Cryogenics.html Cryogenics]. Scienceclarified.com. Retrieved on 22 July 2012.</ref> Decades later, in 1873 Dutch theoretical scientist [[Johannes Diderik van der Waals]] demonstrated that these gases could be liquefied, but only under conditions of very high pressure and very low temperatures. In 1877, [[Louis Paul Cailletet]] in France and [[Raoul Pictet]] in Switzerland succeeded in producing the first droplets of [[liquid air]] at {{convert|-195|C|F K}}. This was followed in 1883 by the production of liquid oxygen {{convert|-218|C|F K}} by the Polish professors [[Zygmunt Wróblewski]] and [[Karol Olszewski]].

Scottish chemist and physicist [[James Dewar]] and Dutch physicist [[Heike Kamerlingh Onnes]] took on the challenge to liquefy the remaining gases, hydrogen and [[helium]]. In 1898, after 20 years of effort, Dewar was the first to liquefy hydrogen, reaching a new low-temperature record of {{convert|-252|C|F K}}. However, Kamerlingh Onnes, his rival, was the first to liquefy helium, in 1908, using several precooling stages and the [[Hampson–Linde cycle]]. He lowered the temperature to the boiling point of helium {{convert|-269|C|F K}}. By reducing the pressure of the liquid helium, he achieved an even lower temperature, near 1.5 K. These were the [[Lowest temperature recorded on Earth|coldest temperatures achieved on Earth]] at the time and his achievement earned him the [[Nobel Prize]] in 1913.<ref name="nobel">{{Cite web |title=The Nobel Prize in Physics 1913: Heike Kamerlingh Onnes |url=https://www.nobelprize.org/nobel_prizes/physics/laureates/1913/onnes-bio.html |access-date=24 April 2012 |publisher=Nobel Media AB}}</ref> Kamerlingh Onnes would continue to study the properties of materials at temperatures near absolute zero, describing [[superconductivity]] and [[superfluids]] for the first time.

==Negative temperatures==
{{Main|Negative temperature}}

Temperatures below zero on the Celsius or Fahrenheit scales are simply colder than the zero points of those scales. In contrast, certain isolated systems can achieve [[negative thermodynamic temperature]]s (in kelvins), which are not colder than absolute zero, but paradoxically hotter than any positive temperature. If a negative-temperature system and a positive-temperature system come in contact, heat flows from the negative to the positive-temperature system.<ref name="Chase">{{Cite web |last=Chase |first=Scott |title=Below Absolute Zero -What Does Negative Temperature Mean? |url=http://www.phys.ncku.edu.tw/mirrors/physicsfaq/ParticleAndNuclear/neg_temperature.html |url-status=dead |archive-url=https://web.archive.org/web/20110815144418/http://www.phys.ncku.edu.tw/mirrors/physicsfaq/ParticleAndNuclear/neg_temperature.html |archive-date=15 August 2011 |access-date=2 July 2010 |website=The Physics and Relativity FAQ}}</ref><ref name=":1">{{cite book |last1=Kittel |first1=C. |author1-link=Charles Kittel |title=Thermal Physics |last2=Kroemer |first2=H. |author2-link=Herbert Kroemer |publisher=[[W. H. Freeman]] |year=1980 |isbn=978-0-7167-1088-2 |edition=2nd |pages=460–463}}</ref>

Negative temperatures can only occur in systems that have an upper limit to the energy they can contain. In these cases, adding energy can decrease [[Entropy (statistical thermodynamics)|entropy]], reversing the usual relationship between energy and temperature. This leads to a negative thermodynamic temperature. However, such conditions only arise in specialized, quasi-equilibrium systems such as collections of [[Spin (physics)|spins]] in a magnetic field. In contrast, ordinary systems with translational or vibrational motion have no upper energy limit, so their temperatures are always positive.<ref name="Chase" /><ref name=":1" />

==Very low temperatures==
[[File:Boomerang nebula.jpg|thumb|right|The rapid expansion of gases leaving the [[Boomerang Nebula]], a bi-polar, filamentary, likely proto-planetary nebula in Centaurus, has a temperature of 1 K, the lowest observed outside of a laboratory.]]
[[File:Bose Einstein condensate.png|right|thumb|Velocity-distribution data of a gas of [[rubidium]] atoms at a temperature within a few billionths of a degree above absolute zero. Left: just before the appearance of a Bose–Einstein condensate. Center: just after the appearance of the condensate. Right: after further evaporation, leaving a sample of nearly pure condensate.]]

The average temperature of the universe today is approximately {{convert|2.73|K|C F|abbr=on}}, based on measurements of [[cosmic microwave background]] radiation.<ref>{{Cite web |last=Kruszelnicki, Karl S. |date=25 September 2003 |title=Coldest Place in the Universe 1 |url=http://www.abc.net.au/science/articles/2003/09/25/947116.htm |access-date=24 September 2012 |publisher=Australian Broadcasting Corporation}}</ref><ref>{{Cite web |date=3 August 2004 |title=What's the temperature of space? |url=http://www.straightdope.com/columns/read/2172/whats-the-temperature-of-space |access-date=24 September 2012 |publisher=The Straight Dope}}</ref> Standard models of the [[future of an expanding universe|future expansion of the universe]] predict that the average temperature of the universe is decreasing over time.<ref>{{Cite journal |last=John |first=Anslyn J. |date=25 August 2021 |title=The building blocks of the universe |journal=HTS Teologiese Studies/Theological Studies |volume=77 |issue=3 |doi=10.4102/hts.v77i3.6831 |s2cid=238730757 |doi-access=free}}</ref> This temperature is calculated as the mean density of energy in space; it should not be confused with the mean [[electron temperature]] (total energy divided by particle count) which has increased over time.<ref>{{Cite news |date=10 November 2020 |title=History of temperature changes in the Universe revealed—First measurement using the Sunyaev-Zeldovich effect |url=https://www.ipmu.jp/en/20201110-CosmicThermal_History |language=en |agency=Kavli Institute for the Physics and Mathematics of the Universe}}</ref>

Absolute zero cannot be achieved, although it is possible to reach temperatures close to it through the use of [[Evaporative cooling (atomic physics)|evaporative cooling]], [[cryocooler]]s, [[dilution refrigerator]]s,<ref>{{Cite journal |last=Zu |first=H. |last2=Dai |first2=W. |last3=de Waele |first3=A. T. A. M. |year=2022 |title=Development of Dilution refrigerators – A review |journal=Cryogenics |volume=121 |doi=10.1016/j.cryogenics.2021.103390 |issn=0011-2275 |s2cid=244005391}}</ref> and [[Magnetic refrigeration#Nuclear demagnetization|nuclear adiabatic demagnetization]]. The use of [[laser cooling]] has produced temperatures of less than a billionth of a kelvin.<ref>{{Cite web |last=Catchpole, Heather |date=4 September 2008 |title=Cosmos Online – Verging on absolute zero |url=http://www.cosmosmagazine.com/features/online/2176/verging-absolute-zero |url-status=dead |archive-url=https://web.archive.org/web/20081122144155/http://www.cosmosmagazine.com/features/online/2176/verging-absolute-zero |archive-date=22 November 2008}}</ref> At very low temperatures in the vicinity of absolute zero, matter exhibits many unusual properties, including [[superconductivity]], [[superfluidity]], and [[Bose–Einstein condensate|Bose–Einstein condensation]]. To study such [[phenomena]], scientists have worked to obtain even lower temperatures.
* In November 2000, [[nuclear spin]] temperatures below {{nowrap|100 picokelvin}} were reported for an experiment at the [[Helsinki University of Technology]]'s Low Temperature Lab in [[Espoo]], [[Finland]]. However, this was the temperature of one particular [[Degrees of freedom (physics and chemistry)|degree of freedom]]—a [[quantum]] property called nuclear spin—not the overall average [[thermodynamic temperature]] for all possible degrees in freedom.<ref>{{Cite book |last=Knuuttila |first=Tauno |url=http://www.hut.fi/Yksikot/Kirjasto/Diss/2000/isbn9512252147 |title=Nuclear Magnetism and Superconductivity in Rhodium |publisher=Helsinki University of Technology |year=2000 |isbn=978-951-22-5208-4 |location=Espoo, Finland |access-date=11 February 2008 |archive-url=https://web.archive.org/web/20010428173229/http://www.hut.fi/Yksikot/Kirjasto/Diss/2000/isbn9512252147/ |archive-date=28 April 2001 |url-status=dead}}</ref><ref>{{Cite press release |title=Low Temperature World Record |date=8 December 2000 |publisher=Low Temperature Laboratory, Teknillinen Korkeakoulu |url=http://ltl.hut.fi/Low-Temp-Record.html |access-date=11 February 2008 |url-status=live |archive-url=https://web.archive.org/web/20080218053521/http://ltl.hut.fi/Low-Temp-Record.html |archive-date=18 February 2008}}</ref>
* In February 2003, the [[Boomerang Nebula]] was observed to have been releasing gases at a speed of {{Convert|500000|km/h|abbr=on}} for the last 1,500 years. This has cooled it down to approximately 1 K, as deduced by astronomical observation, which is the lowest natural temperature ever recorded.<ref>{{Cite journal |last=Sahai |first=Raghvendra |last2=Nyman, Lars-Åke |year=1997 |title=The Boomerang Nebula: The Coldest Region of the Universe? |journal=The Astrophysical Journal |volume=487 |issue=2 |pages=L155–L159 |bibcode=1997ApJ...487L.155S |doi=10.1086/310897 |s2cid=121465475 |doi-access=free |hdl=2014/22450}}</ref>
* In November 2003, [[90377 Sedna]] was discovered and is one of the coldest known objects in the Solar System, with an average surface temperature of {{cvt|-240|C|K F|sigfig=2}},<ref>{{Cite web |title=Mysterious Sedna {{!}} Science Mission Directorate |url=https://science.nasa.gov/science-news/science-at-nasa/2004/16mar_sedna/#:~:text=NASA%27s%20new%20Spitzer%20Space%20Telescope%20also%20looked%20for,minus%20240%20degrees%20Celsius%20(minus%20400%20degrees%20Fahrenheit). |access-date=25 November 2022 |website=science.nasa.gov}}</ref> due to its extremely far orbit of 903 [[astronomical unit]]s.
* In May 2005, the [[European Space Agency]] proposed research in space to achieve [[femto-|femtokelvin]] temperatures.<ref>{{Cite web |title=Scientific Perspectives for ESA's Future Programme in Life and Physical sciences in Space |url=http://www.esf.org/fileadmin/Public_documents/Publications/Scientific_Perspectives_for_ESA_s_Future_Programme_in_Life_and_Physical_Sciences_in_Space.pdf |url-status=dead |archive-url=https://web.archive.org/web/20141006024523/http://www.esf.org/fileadmin/Public_documents/Publications/Scientific_Perspectives_for_ESA_s_Future_Programme_in_Life_and_Physical_Sciences_in_Space.pdf |archive-date=6 October 2014 |access-date=28 March 2014 |website=esf.org}}</ref>
* In May 2006, the Institute of Quantum Optics at the [[University of Hannover]] gave details of technologies and benefits of femtokelvin research in space.<ref>{{Cite web |title=Atomic Quantum Sensors in Space |url=http://www.physics.ucla.edu/quantum_to_cosmos/q2c06/Ertmer.pdf |url-status=live |archive-url=https://ghostarchive.org/archive/20221009/http://www.physics.ucla.edu/quantum_to_cosmos/q2c06/Ertmer.pdf |archive-date=9 October 2022 |website=University of California, Los Angeles}}</ref>
* In January 2013, physicist Ulrich Schneider of the [[University of Munich]] in Germany reported to have achieved temperatures formally below absolute zero ("[[negative temperature]]") in gases. The gas is artificially forced out of equilibrium into a high potential energy state, which is, however, cold. When it then emits radiation it approaches the equilibrium, and can continue emitting despite reaching formal absolute zero; thus, the temperature is formally negative.<ref>{{Cite web |date=3 January 2013 |title=Atoms Reach Record Temperature, Colder than Absolute Zero |url=http://www.livescience.com/25959-atoms-colder-than-absolute-zero.html |website=livescience.com}}</ref>
* In September 2014, scientists in the [[CUORE]] collaboration at the [[Laboratori Nazionali del Gran Sasso]] in Italy cooled a copper vessel with a volume of one cubic meter to {{cvt|0.006|K|C F|sigfig=6}} for 15 days, setting a record for the lowest temperature in the known universe over such a large contiguous volume.<ref>{{Cite news |title=CUORE: The Coldest Heart in the Known Universe. |url=http://www.interactions.org/cms/?pid=1034217 |access-date=21 October 2014 |publisher=INFN Press Release}}</ref>
* In June 2015, experimental physicists at [[MIT]] cooled molecules in a gas of sodium potassium to a temperature of 500 nanokelvin, and it is expected to exhibit an exotic state of matter by cooling these molecules somewhat further.<ref>{{Cite web |title=MIT team creates ultracold molecules |url=https://newsoffice.mit.edu/2015/ultracold-molecules-0610 |url-status=dead |archive-url=https://web.archive.org/web/20150818112454/http://newsoffice.mit.edu/2015/ultracold-molecules-0610 |archive-date=18 August 2015 |access-date=10 June 2015 |website=Massachusetts Institute of Technology, Massachusetts, Cambridge}}</ref>
* In 2017, [[Cold Atom Laboratory]] (CAL), an experimental instrument was developed for launch to the [[International Space Station]] (ISS) in 2018.<ref>{{Cite news |date=5 September 2017 |title=Coolest science ever headed to the space station |url=https://www.science.org/content/article/coolest-science-ever-headed-space-station |access-date=24 September 2017 |work=Science {{!}} AAAS |language=en}}</ref> The instrument has created extremely cold conditions in the [[microgravity]] environment of the ISS leading to the formation of [[Bose–Einstein condensate]]s. In this space-based laboratory, temperatures as low as {{nowrap|1 picokelvin}} are projected to be achievable, and it could further the exploration of unknown [[Quantum mechanics|quantum mechanical]] phenomena and test some of the most fundamental [[laws of physics]].<ref name="NASA Cold Atom Laboratory Mission">{{Cite web |date=2017 |title=Cold Atom Laboratory Mission |url=http://coldatomlab.jpl.nasa.gov/mission/ |url-status=dead |archive-url=https://web.archive.org/web/20130329092843/http://coldatomlab.jpl.nasa.gov/mission/ |archive-date=29 March 2013 |access-date=22 December 2016 |website=Jet Propulsion Laboratory |publisher=NASA}}</ref><ref name="CALnasa">{{Cite web |date=26 September 2014 |title=Cold Atom Laboratory Creates Atomic Dance |url=http://www.nasa.gov/mission_pages/station/research/news/cold_atom_lab/ |url-status=dead |archive-url=https://web.archive.org/web/20210708201720/https://www.nasa.gov/mission_pages/station/research/news/cold_atom_lab/ |archive-date=8 July 2021 |access-date=21 May 2015 |website=NASA News}}</ref>
* The current world record for effective temperatures was set in 2021 at {{nowrap|38 picokelvin}} through matter-wave lensing of rubidium [[Bose–Einstein condensate]]s.<ref name=":0">{{Cite journal |last=Deppner |first=Christian |last2=Herr |first2=Waldemar |last3=Cornelius |first3=Merle |last4=Stromberger |first4=Peter |last5=Sternke |first5=Tammo |last6=Grzeschik |first6=Christoph |last7=Grote |first7=Alexander |last8=Rudolph |first8=Jan |last9=Herrmann |first9=Sven |last10=Krutzik |first10=Markus |last11=Wenzlawski |first11=André |date=30 August 2021 |title=Collective-Mode Enhanced Matter-Wave Optics |url=https://link.aps.org/doi/10.1103/PhysRevLett.127.100401 |journal=Physical Review Letters |language=en |volume=127 |issue=10 |pages=100401 |bibcode=2021PhRvL.127j0401D |doi=10.1103/PhysRevLett.127.100401 |issn=0031-9007 |pmid=34533345 |s2cid=237396804}}</ref>

==See also==
{{Portal|Physics}}
{{Div col|colwidth=22em}}
* [[Degenerate matter]]
* [[Kelvin]] (unit of temperature)
* [[Charles's law]]
* [[Heat]]
* [[International Temperature Scale of 1990]]
* [[Orders of magnitude (temperature)]]
* [[Thermodynamic temperature]]
* [[Triple point]]
* [[Ultracold atom]]
* [[Kinetic energy]]
* [[Entropy]]
* [[Planck temperature]] and [[Hagedorn temperature]], hypothetical upper limits to the thermodynamic temperature scale
{{colend}}

==References==
{{Reflist|30em}}

==Further reading==
* {{Cite book |last=Herbert B. Callen |url=https://archive.org/details/thermodynamicsin0000call |title=Thermodynamics |publisher=John Wiley & Sons |year=1960 |isbn=978-0-471-13035-2 |location=New York |chapter=Chapter 10 |oclc=535083 |chapter-url=https://archive.org/details/thermodynamicsin00call |url-access=registration |chapter-url-access=registration}}
* {{Cite book |last=Herbert B. Callen |title=Thermodynamics and an Introduction to Thermostatistics |publisher=John Wiley & Sons |year=1985 |isbn=978-0-471-86256-7 |edition=Second |location=New York}}
* {{Cite book |last=E.A. Guggenheim |title=Thermodynamics: An Advanced Treatment for Chemists and Physicists |publisher=North Holland Publishing |year=1967 |isbn=978-0-444-86951-7 |edition=Fifth |location=Amsterdam |oclc=324553}}
* {{Cite book |last=George Stanley Rushbrooke |url=https://archive.org/details/in.ernet.dli.2015.476050 |title=Introduction to Statistical Mechanics |publisher=Clarendon Press |year=1949 |location=Oxford |oclc=531928}}
* [https://www.bipm.org/en/search?p_p_id=search_portlet&p_p_lifecycle=2&p_p_state=normal&p_p_mode=view&p_p_resource_id=%2Fdownload%2Fpublication&p_p_cacheability=cacheLevelPage&_search_portlet_dlFileId=41507086&p_p_lifecycle=1&_search_portlet_javax.portlet.action=search&_search_portlet_formDate=1644345579131&_search_portlet_query=absolute+zero&_search_portlet_source=BIPM BIPM Mise en pratique - Kelvin - Appendix 2 - SI Brochure].

==External links==
* [https://www.pbs.org/wgbh/nova/zero/ "Absolute zero"]: a two part ''[[Nova (American TV series)|NOVA]]'' episode [[List of NOVA episodes#Season 35: 2007–2008|originally aired January 2008]]
* [https://web.archive.org/web/20080509100512/http://www.pa.msu.edu/~sciencet/ask_st/012992.html "What is absolute zero?"] ''Lansing State Journal''
{{Portal bar|Physics|Chemistry|Climate change}}
{{Authority control}}
{{DEFAULTSORT:Absolute Zero}}
[[Category:Cold]]
[[Category:Cryogenics]]
[[Category:Temperature]]

Inch

2025-07-24T18:09:27Z

45.232.105.68:

{{Short description|Unit of length}}
{{Redirect|Inches||Inch (disambiguation)}}
{{use British English|date=August 2021}}
{{Use dmy dates|date=April 2022}}
{{Infobox unit
| image = Inch tape.jpg
| caption = A [[measuring tape]] with inches
| symbol = in
| symbol2 = {{pprime}} (the [[double prime]])<ref name="Unicode-U2000">{{cite web |url=http://unicode.org/charts/PDF/U2000.pdf |title=The Unicode Standard 12.1 — General Punctuation ❰ Range: 2000—206F ❱ |author=Unicode Consortium |date=2019 |website=Unicode.org}}</ref>
| standard = [[Imperial units|Imperial]]/[[US customary units|US]] units
| quantity = [[Length]]
| units2 = [[Metric system|Metric]] ([[SI]]) units
| inunits2 = 25.4 [[millimetre|mm]]
| units1 = Imperial/US units
| inunits1 = {{sfrac|36}} [[yard (unit)|yd]] or {{sfrac|12}} [[foot (unit)|ft]]
}}
[[File:3 inch zoll pipe.jpg|thumb|A fire hydrant marked as 3-inch]]

The '''inch''' (symbol: '''in''' or '''[[prime (symbol)|{{pprime}}]]''') is a [[Units of measurement|unit]] of [[length]] in the [[imperial units|British Imperial]] and the [[United States customary units|United States customary]] [[System of measurement|systems of measurement]]. It is equal to {{sfrac|1|36}} [[yard]] or {{sfrac|1|12}} of a [[foot (unit)|foot]]. Derived from the [[Uncia (unit)|Roman uncia]] ("twelfth"), the word ''inch'' is also sometimes used to translate similar units in other measurement systems, [[anthropic units|usually understood as deriving]] from the width of the human thumb.

Standards for the exact length of an inch have varied in the past, but since the adoption of the [[international yard]] during the 1950s and 1960s the inch has been based on the [[metric system]] and defined as exactly 25.4{{nbsp}}[[Millimetre|mm]].

{{anchor|Etymology}}
==Name==
The English word "inch" ({{langx|ang|ynce}}) was an early borrowing from [[Latin]] ''{{lang|la|uncia}}'' ("one-twelfth; [[Roman inch]]; [[Roman ounce]]").<ref>{{citation |contribution=inch, ''n.1'' |title=Oxford English Dictionary |location=Oxford |publisher=Oxford University Press }}.</ref> The vowel change from Latin {{IPA|/u/}} to Old English {{IPA|/y/}} (which became Modern English {{IPA|/ɪ/}}) is known as [[Germanic umlaut|umlaut]].{{citation needed|date=October 2022}} The consonant change from the Latin {{IPA|/k/}} (spelled ''c'') to English {{IPA|/tʃ/}} is [[Palatalization (sound change)|palatalisation]]. Both were features of [[Old English phonology]]; see {{section link|Phonological history of Old English|Palatalization}} and {{section link|Germanic umlaut|I-mutation in Old English}} for more information.

"Inch" is cognate with "[[ounce]]" ({{langx|ang|ynse}}), whose separate pronunciation and spelling reflect its reborrowing in [[Middle English]] from [[Anglo-Norman language|Anglo-Norman]] ''unce'' and ''ounce''.<ref>{{citation |contribution=ounce, ''n.1'' |title=Oxford English Dictionary |location=Oxford |publisher=Oxford University Press }}.</ref>

In many other European languages, the word for "inch" is the same as or derived from the word for "thumb", as a man's thumb is about an inch wide (and this was even sometimes used to define the inch<ref>{{Cite web|url=https://www.britannica.com/science/inch|title=Inch {{!}} unit of measurement|website=Encyclopedia Britannica|language=en|access-date=28 March 2019}}</ref>). In the [[Dutch language]] a term for inch is ''engelse duim'' (english thumb).<ref>{{cite web |url=https://onzetaal.nl/taalloket/duim-lengtemaat |title=duim - lengtemaat |publisher=Genootschap Onze Taal|access-date=22 October 2022}}</ref><ref>{{cite web |url=https://www.omrekenen.nl/duim/ |title=duim |date=24 May 2020 |access-date=22 October 2022}}</ref> Examples include {{langx|ca|polzada}} ("inch") and ''{{lang|ca|polze}}'' ("thumb"); {{langx|cs|palec}} ("thumb"); Danish and {{langx|no|tomme}} ("inch") ''{{lang|no|tommel}}'' ("thumb"); {{langx|nl|duim}} (whence {{langx|af|duim}} and {{langx|ru|дюйм}}); {{langx|fr|pouce}}; {{lang-ka|დუიმი}}, {{langx|hu|hüvelyk}}; {{langx|it|pollice}}; {{langx|pt|polegada}} ("inch") and ''{{lang|pt|polegar}}'' ("thumb"); ("duim"); {{langx|sk|palec}} ("thumb"); {{langx|es|pulgada}} ("inch") and ''{{lang|es|pulgar}}'' ("thumb"); and {{langx|sv|tum}} ("inch") and ''tumme'' ("thumb").

== Usage ==
===Imperial or hybrid countries===
The inch is a commonly used customary unit of length in the United States,<ref>{{cite web |url=http://corpus.byu.edu/coca/ |title=Corpus of Contemporary American English |website=Brigham Young University |location=US |access-date=5 December 2011}} lists 24,302 instances of inch(es) compared to 1548 instances of centimeter(s) and 1343 instances of millimeter(s).</ref> Canada,<ref>{{cite web |url=http://laws-lois.justice.gc.ca/PDF/W-6.pdf |title=Weights and Measures Act |page=37 |via=Justice Laws Website |location=Canada |year=1985 |access-date=11 January 2018}}</ref><ref>{{cite web |url=http://laws-lois.justice.gc.ca/eng/acts/W-6/page-2.html#h-4/ |title=Weights and Measures Act |page=2 |via=Justice Laws Website |location=Canada |date=1 August 2014 |access-date=18 December 2014}} Canadian units (5) The Canadian units of measurement are as set out and defined in Schedule II, and the symbols and abbreviations therefore are as added pursuant to subparagraph 6(1)(b)(ii).</ref> and the United Kingdom.<ref name=bis/> For the United Kingdom, guidance on public sector use states that, since 1 October 1995, without time limit, the inch (along with the foot) is to be used as a primary unit for road signs and related measurements of distance (with the possible exception of clearance heights and widths)<ref>{{cite web |url=http://www.legislation.gov.uk/uksi/2002/3113/schedule/2/made |title=The Traffic Signs Regulations and General Directions 2002 - No. 3113 - Schedule 2 - Regulatory Signs |publisher=The National Archives |location=UK |year=2002 |access-date=25 April 2013}}</ref> and may continue to be used as a secondary or supplementary indication following a metric measurement for other purposes.<ref name=bis>{{cite web |url=http://www.bis.gov.uk/assets/bispartners/nmo/docs/legislation/legislation/units-of-measurement/gnotes-for-public-sector-on-use-of-metric.pdf |archive-url=https://web.archive.org/web/20110704232045/http://www.bis.gov.uk/assets/bispartners/nmo/docs/legislation/legislation/units-of-measurement/gnotes-for-public-sector-on-use-of-metric.pdf |url-status=dead |archive-date=4 July 2011 |title=Guidance Note on the use of Metric Units of Measurement by the Public Sector |publisher=Department for Business Innovation and Skills |location=UK |year=2007 |access-date=12 December 2014}}</ref>

===Worldwide===
Inches are used for display screens (e.g. [[television]]s and computer monitors) worldwide. It is the official [[Japanese units of measurement#Imperial units|Japanese standard]] for electronic parts, especially display screens, and is the industry standard throughout continental Europe for display screens ([[Germany]] being one of few countries to supplement it with centimetres in most stores<ref>{{Cite web|url=https://www.otto.de/technik/fernseher/|title=Fernseher|publisher=[[Otto GmbH]]|language=de|access-date=28 December 2023}}</ref>).

Inches are commonly used to specify the diameter of vehicle wheel rims, and the corresponding inner diameter of tyres in [[tyre code]]s.<ref>{{Cite web|url=https://www.michelin.co.uk/auto/advice/tyre-basics/tyre-markings-explained|title=Tyre Sizing|access-date=14 May 2025}}</ref>

===Technical details===

The international standard symbol for inch is '''in''' (see [[ISO 31-1]], Annex A) but traditionally the inch is denoted by a [[Prime (symbol)|double prime]], which is often approximated by a [[quotation mark|double quote]] symbol, and the [[Foot (unit)|foot]] by a [[Prime (symbol)|prime]], which is often approximated by an [[apostrophe (mark)|apostrophe]]. For example; ''{{nowrap|three feet, two inches}}'' can be written as 3{{prime}} 2{{pprime}}. (This is akin to how the [[minute|first]] and [[second]] "cuts" of the [[hour]] are likewise indicated by prime and double prime symbols, and also the [[Minute of arc|first]] and [[Second of arc|second]] cuts of the [[Degree (angle)|degree]].)

Subdivisions of an inch are typically written using [[dyadic rational|dyadic fractions]] with odd number numerators; for example, ''{{nowrap|two and three-eighths of an inch}}'' would be written as {{sfrac|2|3|8}}{{pprime}} and not as 2.375{{pprime}} nor as {{sfrac|2|6|16}}{{pprime}}. However, for engineering purposes fractions are commonly given to three or four places of decimals and have been for many years.<ref>{{cite book|last1=Flatchet|first1=E|last2=Petiet|first2=J|title=The student's guide to the locomotive engine|url=https://archive.org/details/studentsguideto00ptgoog|date=1849|publisher=John Williams and Co|page=xi|quote=One Metre is equal to ... 30.371 inches"}}</ref><ref>{{cite book|last=Parkinson|first=A C |title=Intermediate Engineering Drawing|date=1967|edition=sixth|page=11|quote=The basic major dia is actually 1.309 in.}}</ref>

=== Equivalents===
{{calculator|id=in|type=number|size=4|default=1}} international inch is equal to:
{{div col|colwidth=30em}}
* {{calculator|id=cm|type=plain|default=2.54|formula=in*2.54|decimals=1|NaN-text=0}} [[centimeter]]s (1 inch is exactly 2.54 cm)
* {{calculator|id=mm|type=plain|default=25.4|formula=in*25.4|decimals=1|NaN-text=0}} [[millimetre]]s (1 inch is exactly 25.4 mm)
* {{sfrac|{{calculator|id=numeratorfeet|type=plain|default=1|formula=in|NaN-text=0}}|12}} or {{calculator|id=feet|type=plain|default=0.08333|formula=in/12|NaN-text=0}} [[foot (unit)|feet]] (approximately)
* {{sfrac|{{calculator|id=numeratoryards|type=plain|default=1|formula=in|NaN-text=0}}|36}} or {{calculator|id=yard|type=plain|default=0.02777|formula=in/36|NaN-text=0}} [[yard]]s (approximately)
* {{calculator|id=tenths|type=plain|default=10000|formula=in*10000|NaN-text=0}} '[[Thousandth of an inch#Tenths|tenths]]'{{efn|A tenth of a [[thousandth of an inch|thou]], used in [[machining]].}}
* {{calculator|id=thou|type=plain|default=1000|formula=in*1000|NaN-text=0}} [[Thousandth of an inch|thou]]{{efn|Used in [[machining]] and [[papermaking]].}} or mil{{efn|Formerly used in [[American English]] but now often avoided to prevent confusion with [[millimetre]]s.}}
* {{calculator|id=points|type=plain|default=100|formula=in*100|NaN-text=0}} points{{efn|Used by the Australian [[Bureau of Meteorology]] for measuring rainfall until 1973<ref>{{cite web |url=http://www.bom.gov.au/climate/cdo/about/definitionsrain.shtml |title=Climate Data Online – definition of rainfall statistics |publisher=[[Bureau of Meteorology]] |location=Australia |access-date=10 June 2012}}</ref>}} or gries{{efn|name=locke|Part of [[John Locke]]'s proposal for decimalization of English measures<ref>{{citation |last=Locke |first=John |author-link=John Locke |display-authors=0 |contribution=Of Human Understanding |page=[https://books.google.com/books?id=3n8PAAAAQAAJ&pg=PA293 293] |title=The Works of John Locke Esq., ''Vol. I'' |location=London |publisher=John Churchill |date=1714 |url=https://books.google.com/books?id=3n8PAAAAQAAJ }}.</ref>}}
* {{calculator|id=pointsTypography|type=plain|default=72|formula=in*72|NaN-text=0}} [[Point (typography)|PostScript point]]s{{efn|The typographic point was originally {{sfrac|1|9}} of the height of a (capital) letter ([[cap height]]) but later acquired a number of different absolute definitions; see [[Point (typography)#History|Point (typography) § History]] for details.}}
* {{calculator|id=line10|type=plain|default=10|formula=in*10|NaN-text=0}},{{efn|Used in [[gunmaking]].}}<ref group=lower-alpha name=locke/> {{calculator|id=line12|type=plain|default=12|formula=in*12|NaN-text=0}},{{efn|Used in [[botany]].}} or {{calculator|id=line40|type=plain|default=40|formula=in*40|NaN-text=0}}{{efn|Used in [[button (clothing)|button]] manufacturing.}} [[line (unit)|lines]]
* {{calculator|id=pica|type=plain|default=6|formula=in*6|NaN-text=0}} [[Pica (typography)|computer picas]]{{efn|Used in [[typography]].}}
* {{calculator|id=barleycorn|type=plain|default=3|formula=in*3|NaN-text=0}} [[Barleycorn (unit)|barleycorns]]{{efn|Used in American and British [[shoe size]]s.}}
* {{calculator|id=ussurveyin|type=plain|default=0.999998|formula=in*0.999998|NaN-text=0}} [[#US survey inches|US survey inches]]
* {{sfrac|{{calculator|id=numeratorPalm|type=plain|default=1|formula=in|NaN-text=0}}|3}} or {{calculator|id=palms|type=plain|default=0.333|formula=in/3|NaN-text=0}} [[palm (unit)|palms]] (approximately)
* {{sfrac|{{calculator|id=numeratorhand|type=plain|default=1|formula=in|NaN-text=0}}|4}} or {{calculator|id=hand|type=plain|default=0.25|formula=in/4|NaN-text=0}} [[hand (unit)|hands]]{{efn|Used in measuring the height of [[horse]]s.}}
{{Div col end}}

== History ==
[[File:Inch converter.jpg|thumb|Mid-19th-century tool for converting between different standards of the inch]]

The earliest known reference to the inch in England is from the ''[[Laws of Æthelberht]]'' dating to the early 7th century, surviving in a single manuscript, the ''[[Textus Roffensis]]'' from 1120.<ref name="GoetzJarnut2003">{{cite book |last1=Goetz |first1=Hans-Werner |last2=Jarnut |first2=Jörg |last3=Pohl |first3=Walter |author-link3=Walter Pohl |title=Regna and Gentes: The Relationship Between Late Antique and Early Medieval Peoples and Kingdoms in the Transformation of the Roman World |url=https://books.google.com/books?id=RovRlJkrncEC&pg=PA33 |year=2003 |publisher=BRILL |isbn=978-90-04-12524-7 |page=33}}</ref> Paragraph LXVII sets out the fine for wounds of various depths: one inch, one shilling; two inches, two shillings, etc.{{efn|{{langx|ang|Gif man þeoh þurhstingð, stice ghwilve vi scillingas. Gife ofer ynce, scilling. æt twam yncum, twegen. ofer þry, iii scill.}} Translation (taken from {{harvnb|Attenborough|1922|p=13}}): If a thigh is pierced right through, 6 shillings compensation shall be paid for each stab. For a stab over an inch [deep], 1 shilling; for a stab between 2 and 3 inches, 2 shillings; for a stab over 3 inches 3 shillings.<ref name="Wilkins1871">{{cite book |last=Wilkins |first=David |title=Councils and Ecclesiastical Documents Relating to Great Britain and Ireland: English church during the Anglo-Saxon period: A.D. 595-1066. |url=https://archive.org/details/councilsandeccl04wilkgoog |access-date=18 December 2014 |year=1871 |publisher=Clarendon Press |location=Oxford, UK |page=[https://archive.org/details/councilsandeccl04wilkgoog/page/n72 48]}}</ref><ref name="Duncan1984">{{cite book |last=Duncan |first=Otis Dudley |author-link=Otis Dudley Duncan |title=Notes on social measurement: historical and critical |url=https://books.google.com/books?id=5c459mDugI0C&pg=PA87 |year=1984 |publisher=Russell Sage Foundation |location=US |isbn=978-0-87154-219-9 |page=87}}</ref>}}

An Anglo-Saxon unit of length was the [[English units|barleycorn]]. After 1066, 1 inch was equal to 3 barleycorns, which continued to be its legal definition for several centuries, with the barleycorn being the base unit.<ref name=Klein>{{cite book |title=The world of measurements: masterpieces, mysteries and muddles of metrology |url=https://archive.org/details/worldofmeasureme0000klei |url-access=registration |first=H. Arthur |last=Klein |publisher=Simon and Schuster |location=New York, US |year=1974|isbn=9780671215651 }}</ref> One of the earliest such definitions is that of 1324, where the legal definition of the inch was set out in a statute of [[Edward II of England]], defining it as "three grains of [[barley]], dry and round, placed end to end, lengthwise".<ref name=Klein />

Similar definitions are recorded in both English and Welsh medieval law tracts.<ref>{{cite book |pages=310 |title=Northumbria's Golden Age |first1=Jane |last1=Hawkes |first2=Susan |last2=Mills |publisher=Sutton |location=UK |year=1999 |isbn=978-0-7509-1685-1}}</ref> One, dating from the first half of the 10th century, is contained in the Laws of [[Hywel Dda]] which superseded those of [[Dyfnwal Moelmud|Dyfnwal]], an even earlier definition of the inch in Wales. Both definitions, as recorded in ''Ancient Laws and Institutes of Wales'' (vol i., pp. 184, 187, 189), are that "three lengths of a barleycorn is the inch".<ref>{{cite book |title=The Traditionary Annals of the Cymry |url=https://archive.org/details/traditionaryann00willgoog |first=John |last=Williams |chapter=The civil arts – mensuration |pages=[https://archive.org/details/traditionaryann00willgoog/page/n253 243]–245 |location=Tenby, UK |publisher=R. Mason |year=1867}}</ref>

King David I of Scotland in his Assize of Weights and Measures (c. 1150) is said to have defined the Scottish inch as the width of an average man's thumb at the base of the nail, even including the requirement to calculate the average of a small, a medium, and a large man's measures.<ref name="Swinton1789">{{cite book |last1=Swinton |first1 = John| author-link1=John Swinton, Lord Swinton |title=A proposal for uniformity of weights and measures in Scotland |url=https://books.google.com/books?id=kHhbAAAAQAAJ&pg=PA134 |year=1789 |publisher=printed for Peter Hill |page=134}}</ref> However, the oldest surviving manuscripts date from the early 14th century and appear to have been altered with the inclusion of newer material.<ref name="GemmillMayhew2006">{{cite book |first1=Elizabeth |last1=Gemmill |first2=Nicholas |last2=Mayhew |title=Changing Values in Medieval Scotland: A Study of Prices, Money, and Weights and Measures |url=https://books.google.com/books?id=t1hmrzOSEagC&pg=PA113 |date=22 June 2006 |publisher=Cambridge University Press| location=UK |isbn=978-0-521-02709-0 |page=113}}</ref>

In 1814, Charles Butler, a mathematics teacher at [[Cheam School]], recorded the old legal definition of the inch to be "three grains of sound ripe barley being taken out the middle of the ear, well dried, and laid end to end in a row", and placed the barleycorn, not the inch, as the base unit of the English Long Measure system, from which all other units were derived.<ref name=Butler>{{cite book |pages=[https://archive.org/details/aneasyintroduct01butlgoog/page/n64 61] |title=An Easy Introduction to the Mathematics |url=https://archive.org/details/aneasyintroduct01butlgoog |first=Charles |last=Butler |location=Oxford, UK |publisher=Bartlett and Newman |year=1814}}</ref> [[John Bouvier]] similarly recorded in his 1843 law dictionary that the barleycorn was the fundamental measure.<ref>{{cite encyclopedia |first=John |last=Bouvier |article=Barleycorn |year=1843 |encyclopedia=A Law Dictionary: With References to the Civil and Other Systems of Foreign Law |pages=188 |location=Philadelphia, US |publisher=T. & J. W. Johnson}}</ref> Butler observed, however, that "[a]s the length of the barley-corn cannot be fixed, so the inch according to this method will be uncertain", noting that a standard inch measure was now [i.e. by 1843] kept in the Exchequer chamber, [[Guildhall, London|Guildhall]], and ''that'' was the legal definition of the inch.<ref name=Butler />

This was a point also made by George Long in his 1842 ''[[Penny Cyclopædia]]'', observing that standard measures had since surpassed the barleycorn definition of the inch, and that to recover the inch measure from its original definition, in case the standard measure were destroyed, would involve the measurement of large numbers of barleycorns and taking their average lengths. He noted that this process would not perfectly recover the standard, since it might introduce errors of anywhere between one hundredth and one tenth of an inch in the definition of a yard.<ref>{{cite encyclopedia |page=436 |article=Weights & Measures, Standard |encyclopedia=The Penny Cyclopædia of the Society for the Diffusion of Useful Knowledge |first=George |last=Long |year=1842 |location=London, UK |publisher=Charles Knight & Co.}}</ref>

Before the adoption of the [[international yard and pound]], various definitions were in use. In the United Kingdom and most countries of the [[Commonwealth of Nations|British Commonwealth]], the inch was defined in terms of the [[Yard#19th-century Britain|Imperial Standard Yard]]. The United States adopted the conversion factor 1 metre = 39.37 inches by an act in 1866.<ref>{{cite book
| first1 = Lewis V
| last1 = Judson
| title = Weights and Measures Standards of the United States - a brief history - NBS publication 447
| url = https://books.google.com/books?id=GXWfglKg11MC&q=1838+gallon+231+congress&pg=PA8
| page = 10–11
| publisher = [[United States Department of Commerce]]
| date = October 1963
}}</ref> In 1893, [[Mendenhall Order|Mendenhall ordered]] the physical realization of the inch to be based on the international prototype metres numbers 21 and 27, which had been received from the [[CGPM]], together with the previously adopted conversion factor.<ref name="Mendenhall">{{cite web |author=T. C. Mendenhall, Superintendent of Standard Weights and Measures |author-link=Thomas Corwin Mendenhall |url=http://physics.nist.gov/Pubs/SP447/app3.pdf |date=5 April 1893 |title=Appendix 6 to the Report for 1893 of the Coast and Geodetic Survey |url-status=dead |archive-url=https://web.archive.org/web/20120930180925/http://physics.nist.gov/Pubs/SP447/app3.pdf |archive-date=30 September 2012 }}</ref>

As a result of the definitions above, the U.S. inch was effectively defined as 25.4000508 mm (with a reference temperature of 68 degrees Fahrenheit) and the UK inch at 25.399977 mm (with a reference temperature of 62 degrees Fahrenheit). When [[Carl Edvard Johansson]] started manufacturing [[gauge blocks]] in inch sizes in 1912, Johansson's compromise was to manufacture gauge blocks with a nominal size of 25.4mm, with a reference temperature of 20 degrees Celsius, accurate to within a few parts per million of both official definitions. Because Johansson's blocks were so popular, his blocks became the ''de facto'' standard for manufacturers internationally,<ref name=":0">{{Cite web|url=http://mitutoyo.com/wp-content/uploads/2013/07/E12016-History-of-The-Gage-Block.pdf#page=8|title=The History of Gauge Blocks|date=2013|website=mitutoyo.com|publisher=Mitutoyo Corporation|page=8|access-date=1 February 2020}}</ref><ref>{{Cite book|url=https://books.google.com/books?id=3rUaAQAAMAAJ&pg=PA293|title=Industrial Standardization and Commercial Standards Monthly|date=October 1943|language=en|access-date=1 February 2020|first=John|last=Gaillard|page=293}}</ref> with other manufacturers of gauge blocks following Johansson's definition by producing blocks designed to be equivalent to his.<ref>{{Cite book|url=https://books.google.com/books?id=NiEEAQAAIAAJ&pg=PA200|title=Measures for Progress. NIST Special Publication, isue 275.|last=Cochrane|first=Rexmond C.|publisher=U.S. Government Printing Office|year=1966|pages=200|language=en|lccn=65-62472}}</ref>

In 1930, the [[BSI Group|British Standards Institution]] adopted an inch of exactly 25.4 mm. The [[American National Standards Institute|American Standards Association]] followed suit in 1933. By 1935, industry in 16 countries had adopted the "industrial inch" as it came to be known,<ref name="MeasuresStandards1936">{{cite conference |url={{google books|id=WDgJAQAAMAAJ|page=RA3-PA4|plain-url=yes}} |conference=National Twenty-Eight Conference on Weights and Measures |title=The Viewpoint of industry concerned with interchangeable manufacturing toward the proposal to standardize the inch |first=Herbert B. |last=Lewis |publisher=National Bureau of Standards |location=US |year=1936 |page=4 |access-date=2 August 2012}}</ref><ref name="WandmacherJohnson1995">{{cite book |last1=Wandmacher |first1=Cornelius |last2=Johnson |first2=Arnold Ivan |title=Metric Units in Engineering--going SI: How to Use the International Systems of Measurement Units (SI) to Solve Standard Engineering Problems |url=https://books.google.com/books?id=v5AGFgpcK_wC&pg=PA265 |year=1995 |publisher=ASCE Publications|isbn=978-0-7844-0070-8|page=265}}</ref> effectively endorsing Johansson's pragmatic choice of conversion ratio.<ref name=":0" />

In 1946, the Commonwealth Science Congress recommended a yard of exactly 0.9144 metres for adoption throughout the British Commonwealth. This was adopted by Canada in 1951;<ref>{{cite journal|title=Announcement on the International Yard and Pound|first=L. E.|last=Howlett|date=1 January 1959|journal=Canadian Journal of Physics|volume=37|issue=1|pages=84|doi=10.1139/p59-014|bibcode=1959CaJPh..37...84H}}</ref><ref name="MeasuresStandards1957">{{cite book |author1=National Conference on Weights and Measures |author2=United States. Bureau of Standards |author3=National Institute of Standards and Technology (US) |author-link3=National Institute of Standards and Technology |title=Report of the ... National Conference on Weights and Measures |url=https://books.google.com/books?id=CEgJAQAAMAAJ&pg=PA45 |year=1957 |publisher=US Department of Commerce, Bureau of Standards |pages=45–6}}</ref> the United States on 1 July 1959;<ref name="FR59-5442">{{cite web |last1=Astin |first1=A.V. |last2=Karo |first2=H. A. |last3=Mueller |first3=F.H. |date=25 June 1959 |url=http://www.ngs.noaa.gov/PUBS_LIB/FedRegister/FRdoc59-5442.pdf |title=Refinement of Values for the Yard and the Pound |publisher=US [[Federal Register]]}}</ref><ref name="Standards1959">{{cite book |author=United States. National Bureau of Standards |author-link=National Institute of Standards and Technology |title=Research Highlights of the National Bureau of Standards |url=https://books.google.com/books?id=4aWN-VRV1AoC&pg=PA13 |year=1959 |publisher=US Department of Commerce, National Bureau of Standards |page=13}}</ref><ref name="JudsonStandards1976">{{cite book|author1=Lewis Van Hagen Judson|author2=United States. National Bureau of Standards|author-link2=National Institute of Standards and Technology|title=Weights and measures standards of the United States: a brief history|url=https://archive.org/details/bub_gb_o4XQ7KCv5E0C|access-date=16 September 2012|year=1976|publisher=Dept. of Commerce, National Bureau of Standards : for sale by the Supt. of Docs., U.S. Govt. Print. Off.|pages=[https://archive.org/details/bub_gb_o4XQ7KCv5E0C/page/n36 30]–1}}</ref> Australia in 1961,<ref>Statutory Rule No. 142.</ref> effective 1 January 1964;<ref>[http://www.comlaw.gov.au/Details/C2004L00578 Australian Government ComLaw ''Weights and Measures (National Standards) Regulations - C2004L00578'']</ref> and the United Kingdom in 1963,<ref>Weights and Measures Act of 1963.</ref> effective on 1 January 1964.<ref>{{cite web |url=http://www.bailii.org/ew/cases/EWHC/Admin/2002/195.html |title=Thoburn v Sunderland City Council [2002] EWHC 195 (Admin) |date=18 February 2002 |publisher=England and Wales High Court |via=British and Irish Legal Information Institute}}</ref> The new standards gave an inch of exactly 25.4 mm, 1.7 millionths of an inch longer than the old imperial inch and 2 millionths of an inch shorter than the old US inch.<ref>{{cite web |url=http://www.npl.co.uk/reference/faqs/on-what-basis-is-one-inch-exactly-equal-to-25.4-mm-has-the-imperial-inch-been-adjusted-to-give-this-exact-fit-and-if-so-when-(faq-length) |archive-url= https://web.archive.org/web/20130126164151/http://www.npl.co.uk/reference/faqs/on-what-basis-is-one-inch-exactly-equal-to-25.4-mm-has-the-imperial-inch-been-adjusted-to-give-this-exact-fit-and-if-so-when-(faq-length) | archive-date = 26 January 2013 |title=On what basis is one inch exactly equal to 25.4 mm? Has the imperial inch been adjusted to give this exact fit and if so when? |publisher=National Physical Laboratory |date=25 March 2010 |access-date=5 April 2013}}</ref><ref name=Astin/>

==Related units==

===US survey inches===
The United States retained the {{sfrac|1|39.37}}-metre definition for surveying, producing a 2 millionth part difference between standard and [[United States customary units#Length|US survey]] inches.<ref name = Astin>A. V. Astin & H. Arnold Karo, (1959), [http://www.ngs.noaa.gov/PUBS_LIB/FedRegister/FRdoc59-5442.pdf ''Refinement of values for the yard and the pound''], Washington DC: National Bureau of Standards, republished on National Geodetic Survey web site and the Federal Register (Doc. 59-5442, Filed, 30 June 1959, 8:45 am)</ref> This is approximately {{sfrac|1|8}} inch per mile; 12.7 kilometres is exactly {{Nts|500000}} standard inches and exactly {{Nts|499999}} survey inches. This difference is substantial when doing calculations in [[State Plane Coordinate System]]s with coordinate values in the hundreds of thousands or millions of feet.

In 2020, the [[National Institute of Standards and Technology]] announced that the U.S. survey foot would "be phased out" on 1 January 2023 and be superseded by the international foot (also known as the foot) equal to 0.3048 metres exactly, for all further applications.<ref>{{Cite web|url=https://www.nist.gov/pml/us-surveyfoot|title=U.S. Survey Foot|last=Materese|first=Robin|date=26 July 2019|website=NIST|language=en|access-date=1 February 2020}}</ref> This implies that the survey inch was replaced by the international inch.

===Continental inches===
{{Main|Roman inch|French inch}}
Before the adoption of the metric system, several European countries had customary units whose name translates into "inch". The French ''[[pouce]]'' measured roughly 27.0 mm, at least when applied to describe the calibre of artillery [[Cannon|pieces]]. The [[Dutch units of measurement|Amsterdam foot]] (''voet'') consisted of 11 Amsterdam inches (''duim''). The Amsterdam foot is about 8% shorter than an English foot.<ref>*{{cite book
|url = {{google book|id=XYVbAAAAQAAJ|page=166|plain-url=yes}}
|title = Allereerste Gronden der Cijferkunst
|first = Jacob
|last = de Gelder
|location = The Hague 
|language = nl
|year = 1824
|pages = 166
|publisher = de Gebroeders van Cleef
|trans-title=Introduction to Numeracy
|access-date = 10 April 2022}}
</ref>

=== Scottish inch ===
The now obsolete [[Obsolete Scottish units of measurement|Scottish inch]] ({{langx|gd|òirleach}}), {{sfrac|12}} of a Scottish foot, was about 1.0016 imperial inches (about {{convert|1.0016|in|mm|disp=output only}}).<ref>{{cite web
|url =https://dsl.ac.uk/entry/snd/snds3729
|title = Dictionary of the Scots Language
|publisher = Scottish Language Dictionaries
|location = Edinburgh
|access-date =22 January 2020}}</ref>

== See also ==
{{div col|colwidth=23em}}
* [[English units]]
* [[Square inch]] and [[Cubic inch]]
* [[International yard and pound]]
* [[Anthropic units]]
* [[Pyramid inch]]
* [[Digit (unit)|Digit]] and [[Line (unit)|Line]]
{{Div col end}}

==Notes==
{{Notelist|2}}

== References ==
===Citations===
{{Reflist|30em}}

===Bibliography===
* {{Citation | last = Attenborough | first = F. L. | author-link = Frederick Attenborough | title = The Laws of the Earliest English Kings | edition = Llanerch Press Facsimile Reprint 2000 | location = Cambridge | publisher = Cambridge University Press | year = 1922 | isbn = 978-1-86143-101-1 |url=https://archive.org/details/cu31924070153519 |access-date= 11 July 2018}}

{{Imperial units}}
{{United States Customary Units}}
{{Authority control}}

[[Category:Customary units of measurement in the United States]]
[[Category:Imperial units]]
[[Category:Units of length]]
[[Category:Obsolete Scottish units of measurement]]

[[fy:Tomme (lingtemaat)]]

Dog paddle

2025-07-22T21:42:45Z

45.232.105.68: live instead of dead link

{{Short description|Swimming style}}
[[File:Golden retriever swimming the doggy paddle.webm|thumb|A [[golden retriever]] swimming the doggy paddle]]
The '''dog paddle''' or '''doggy paddle''' is a simple [[List of swimming styles|swimming style]]. It is characterized by the swimmer lying on their chest and moving their hands and legs alternately in a manner reminiscent of how [[dog]]s and other [[quadrupedal]] [[mammals]] swim.<ref>{{cite book|title=Boys' Own Book: A Complete Encyclopedia of Athletic, Scientific, Outdoor and Indoor Sports|year=1881|publisher=J Miller|author=William Clarke|url=https://books.google.com/books?id=RiAMAAAAYAAJ}}</ref> It is effectively a "trot" in water, instead of land.<ref>{{cite book|title=At the Water's Edge: Fish with Fingers, Whales with Legs, and How Life Came Ashore But Then Went Back to Sea|author=Carl Zimmer|publisher=[[Simon & Schuster]]|year=1999|isbn=0-684-85623-9|url=https://books.google.com/books?id=OZZpBy-lLTgC|page=183}}</ref>

It was the first swimming stroke used by ancient humans, believed to have been learned by observing animals swim.<ref>{{Cite book |last=Colwin |first=Cecil M. |url=https://www.google.com.pe/books/edition/Breakthrough_Swimming/LPF6DwAAQBAJ?hl=en&gbpv=1 |title=Breakthrough Swimming |date=2002-02-20 |publisher=Human Kinetics |isbn=978-1-4925-8500-8 |language=en}}</ref> Prehistoric [[cave paintings]] in [[Egypt]] show figures doing what appears to be the dog paddle.<ref>{{cite book|title=Olympic Swimming and Diving|author=Greg Kehm|page=[https://archive.org/details/olympicswimmingd0000kehm/page/4 4]|isbn=978-1-4042-0970-1|publisher=Rosen|year=2007|url=https://archive.org/details/olympicswimmingd0000kehm/page/4}}</ref>

It is often the first [[List of swimming styles|swimming stroke]] used by young children when they are learning to swim.<ref>{{cite book|title=A Framework for Physical Education in the Early Years|author=H. Manners, M. E. Carroll|year=1995|publisher=Routledge|isbn=0-7507-0417-9|page=110|url=https://books.google.com/books?id=2945yExihiEC}}</ref>

The dog paddle has also been taught as a military swimming stroke when a silent stroke is needed - since neither arms nor legs break the surface.<ref>{{cite book|title=Survival at Sea|author=U.S. Departments of the Army and Air Force|year=1950|publisher=United States Government Printing Office|page=58|url=https://www.scribd.com/doc/76323994/Survival-at-Sea-1950}}</ref>

== See also ==
* [[Human swimming]]
* [[Front crawl]]
* [[Breaststroke]]

== References ==
{{reflist}}

== External links ==
* {{wikihow|Doggy-Paddle|Doggy Paddle}}

{{Swimming styles}}

[[Category:Swimming styles]]

{{swimming-stub}}

Floorball

2025-07-17T19:22:03Z

45.232.105.68: /* Equipment */

{{Short description|Indoor team sport}}
{{Use dmy dates|date=September 2023}}
{{Infobox sport
| image = WFC2018 Czech Republic vs Finland Adam Delong 9.jpg
| alt =
| imagesize =
| caption = A floorball game between the Czech Republic and Finland
| union = [[International Floorball Federation]]
| nickname =
{{Plainlist|
* indoor [[bandy]]
* innebandy
* salibandy
* unihockey
* plastic hockey
|}}
| first = {{Start date and age|df=yes|1960}} – late 1960s in [[Gothenburg]], Sweden
| region = Austria, Belgium, Croatia, Czech Republic, Denmark, Estonia, Finland, Hungary, Germany, Latvia, Lithuania, the Netherlands, Norway, Poland, Slovakia, Slovenia, Sweden, Switzerland, Singapore
| registered =
| clubs = 4396
| contact = Yes
| team = 6, including goalkeeper
| mgender = Yes, and separate competitions
| type = Indoor
| equipment =
{{Plainlist|
* Shoes
* [[Floorball stick]]
* Glasses for safety
|}}
| venue =
| olympic = No
| paralympic = No
| IWGA = 3 (''[[Floorball at the World Games|Since]] in [[Floorball at the 2017 World Games|2017]]'')
}}
'''Floorball''' (also known by [[#Etymology|other names]]) is a sport played with five players and a goalkeeper in each team. It is played indoors with {{convert|96|–|115.5|cm|in|abbr=on|adj=mid|-long}} sticks and a {{convert|70|–|72|mm|in|2|abbr=on| adj=mid|-diameter}} hollow plastic ball with holes. Matches are played in three periods. The sport of [[bandy]] also played a role in the game's development.

The game was invented in [[Sweden]] in the late 1960s.<ref>{{Cite web|url=https://www.theworldgames.org/sports/Floorball-56|title=Floorball {{!}} IWGA|website=www.theworldgames.org|access-date=22 April 2018|archive-date=22 April 2018|archive-url=https://web.archive.org/web/20180422205550/https://www.theworldgames.org/sports/Floorball-56|url-status=live}}</ref> The basic rules were established in 1979 when the first floorball club in the world, Sala IBK, from [[Sala, Sweden|Sala]], was founded in Sweden.<ref name=if>{{cite web |url=http://www.innebandy.se/StatistikHistorik/Innebandyns-fodelse/ |title=Innebandyns födelse – Innebandy.se |website=Innebandy.se |access-date=7 September 2016|language=sv|archive-url=https://web.archive.org/web/20180908194118/http://www.innebandy.se/StatistikHistorik/Innebandyns-fodelse/|archive-date=8 September 2018|url-status=dead}}</ref> Official rules for matches were first written down in 1981.<ref>{{cite web
|last = Houmann
|first = Steen
|publisher = Et samarbejde af Dansk Skoleidræt og Dansk Floorball Union
|title = Skolernes Floorball
|url = http://www.danskfloorball.dk/UserFiles/File/Breddeudvalget/SF2006.pdf
|access-date = 7 September 2016
|date = 2006
|language = da
|archive-url = https://web.archive.org/web/20150402110611/http://www.danskfloorball.dk/UserFiles/File/Breddeudvalget/SF2006.pdf
|archive-date = 2 April 2015
|url-status = dead
}} p. 2</ref>

The sport is organized internationally by the [[International Floorball Federation]] (IFF). As of 2019, there were about 377,000 registered floorball players worldwide,<ref>{{cite web |title=Number of licensed floorball players in 2019 |url=https://floorball.sport/2020/10/01/number-of-licensed-floorball-players-in-2019/ |website=IFF Main Site |date=1 October 2020 |access-date=28 August 2021 |archive-date=13 May 2021 |archive-url=https://web.archive.org/web/20210513033442/https://floorball.sport/2020/10/01/number-of-licensed-floorball-players-in-2019/ |url-status=live }}</ref> up from around 300,000 in 2014.<ref name=ifftoday /> Events include an annual [[Champions Cup (floorball)|Champions Cup]], [[EuroFloorball Cup]] and [[EuroFloorball Challenge]] for club teams and the biennial [[World Floorball Championships]] with separate divisions for men and women. Men's semi-professional club leagues include Finland's [[F-liiga]], Sweden's [[Swedish Super League (men's floorball)|Svenska Superligan]], Switzerland's [[Lidl Unihockey Prime League (Floorball)|Unihockey Prime League]], and the Czech Republic's [[Superliga florbalu]]. Women's semi-professional leagues from the same countries are [[F-liiga (women)|F-liiga]], [[Swedish Super League (women's floorball)|Svenska Superligan]], [[Lidl Unihockey Prime League (women's floorball)|Unihockey Prime League]] and [[Extraliga žen ve florbale|Extraliga žen]].

While the IFF contains 80 members, floorball is most popular where it has been developed the longest, such as the Czech Republic, Denmark, Estonia, Finland, Latvia, Norway, Sweden, and Switzerland. It is gaining popularity in Australia, New Zealand, India,<ref>{{cite web |url=https://www.floorballaustralia.org.au/ |title=Floorball Australia > Home |website=Floorballaustralia.org |access-date=7 September 2016 |archive-date=18 September 2016 |archive-url=https://web.archive.org/web/20160918042325/http://www.floorballaustralia.org.au/ |url-status=live }}</ref> Canada,<ref>{{cite web |url=https://globalnews.ca/video/1762155/what-is-floorball |title=What is floorball? |newspaper=Globalnews.ca |access-date=7 September 2016 |archive-date=28 May 2016 |archive-url=https://web.archive.org/web/20160528202736/http://globalnews.ca/video/1762155/what-is-floorball/ |url-status=dead }}</ref> Germany,<ref>{{cite web |url=https://floorball.de/ |title=Floorball Deutschland |website=Floorball.de |access-date=6 September 2016 |language=de |archive-date=3 September 2016 |archive-url=https://web.archive.org/web/20160903185901/http://www.floorball.de/ |url-status=live }}</ref> Ireland,<ref>{{cite web |url=http://www.killarneyvikings.yolasite.com/about-floorball.php |title=Killarney Vikings |website=Killarneyvikings.yolasite.com |access-date=7 September 2016 |archive-date=4 March 2016 |archive-url=https://web.archive.org/web/20160304092938/http://www.killarneyvikings.yolasite.com/about-floorball.php |url-status=live }}</ref> Japan,<ref>{{cite web |url=https://www.floorball.jp/ |script-title=ja:トップページ |website=Floorball.jp |access-date=7 September 2016 |language=ja |archive-date=3 September 2016 |archive-url=https://web.archive.org/web/20160903192800/http://www.floorball.jp/ |url-status=live }}</ref> Singapore,<ref>{{cite web|url=http://innebandyplaneten.se/?p=6305 |title=Interview with GK from Singapore! |access-date=18 April 2015 |website=innebandyplaneten.se |url-status=dead |archive-url=https://web.archive.org/web/20150418182756/http://innebandyplaneten.se/?p=6305 |archive-date=18 April 2015}}</ref> Malaysia,<ref>{{cite web |url=https://floorballmalaysia.com/ |title=Malaysia Floorball Association |website=Floorballmalaysia.com |access-date=6 September 2016 |archive-date=30 September 2016 |archive-url=https://web.archive.org/web/20160930060341/http://www.floorballmalaysia.com/ |url-status=live }}</ref> the United States,<ref>{{cite web|url=https://www.aftonbladet.se/sportbladet/a/wEVeEo/wayne-gretzky-alskar-innebandy|title="Wayne Gretzky älskar innebandy"|website=Aftonbladet.se|date=18 April 2015 |access-date=6 September 2016|language=sv|archive-date=26 January 2020|archive-url=https://web.archive.org/web/20200126183959/https://www.aftonbladet.se/sportbladet/a/wEVeEo/wayne-gretzky-alskar-innebandy|url-status=live}}</ref> and the United Kingdom.

Floorball was included in the [[World Games]] for the first time in 2017 in [[Wrocław]], Poland, where Sweden became the [[List of 2017 World Games medal winners#Floorball|first team to win a gold medal]].

== Etymology ==
The game of floorball is also known by many other names, such as {{lang|et|'''saalihoki'''|i=no}} (in Estonia), {{lang|fi|'''salibandy'''|i=no}} (in Finland), {{lang|sv|'''innebandy'''|i=no}} (in Sweden and Norway), '''unihockey''' (in Switzerland and Ireland), '''unihokej''' (in Poland), '''Unihockey''' (in Germany) and {{lang|lt|'''grindų riedulys'''|i=no}} (in Lithuania). The names {{lang|fi|salibandy}} and {{lang|sv|innebandy}} are derived from ''bandy'' and translate to "hall bandy" and "indoor bandy" respectively. In Sweden, voices have been raised to get rid of the word {{lang|sv|innebandy}} as name of the sport, to avoid confusions with [[bandy]].<ref>{{cite news|url=https://www.hn.se/sport/wic/jag-%C3%A4r-inte-j%C3%A4ttef%C3%B6rtjust-i-det-1.2132385|title=Jag är inte jätteförtjust i det|publisher=Hallands nyheter|author=Mattias Nilsson|language=Swedish|date=10 January 2014|access-date=1 November 2022|archive-date=1 November 2022|archive-url=https://web.archive.org/web/20221101153530/https://www.hn.se/sport/wic/jag-%C3%A4r-inte-j%C3%A4ttef%C3%B6rtjust-i-det-1.2132385|url-status=live}}</ref><ref>{{cite news|url=https://www.aftonbladet.se/sportbladet/a/nW6qaL/forslaget-bandydistrikt-vill-ta-bort-bandy-ur-innebandyn|title=Förslaget: Ta bort bandy ur innebandy|publisher=Sportbladet|author=Christoffer Million|language=Swedish|date=11 May 2022|access-date=1 November 2022|archive-date=1 November 2022|archive-url=https://web.archive.org/web/20221101153529/https://www.aftonbladet.se/sportbladet/a/nW6qaL/forslaget-bandydistrikt-vill-ta-bort-bandy-ur-innebandyn|url-status=live}}</ref> The name ''unihockey'' is shortened from ''universal hockey'' since it is meant to be a special and simplified hockey form.

== History ==
{{unreliable sources|section||date=February 2022}}
In various forms the game of [[floor hockey]] has been played since the early 20th Century in Canada as a recreational sport, especially in high school gymnasiums, as a playful variant of [[hockey]]. The basic design of floorball sticks is believed to have come from the ice skating team sport of [[bandy]].

By the 1950s and 1960s{{citation needed|reason=Need source because there is some crossover between the history of floor hockey and floorball||date=September 2015}} many public school systems within [[Michigan, United States|Michigan in the United States]] incorporated floorball into their primary and secondary school gym classes. Americans have since claimed to have invented floorball. America held interstate tournaments in the 1960s.<ref>{{cite web |url=http://floorballcoach.org/development-of-floorball/ |title=DEVELOPMENT OF FLOORBALL : Floorball Coach – everything about floorball training |website=Floorballcoach.org |access-date=7 September 2016|url-status=dead|archive-url=https://web.archive.org/web/20191231133641/http://floorballcoach.org/development-of-floorball/|archive-date=31 December 2019}}</ref>

Floorball was formally organized as an international and more organized sport in the late 1970s in [[Gothenburg]], [[Sweden]].<ref name="floorballnation1">{{cite web|title=The History of Floorball|url=http://floorballnation.com.au/history-floorball.html|website=floorballnation.com.au|access-date=7 September 2016|archive-url=https://web.archive.org/web/20130424172015/http://floorballnation.com.au/history-floorball.html|archive-date=24 April 2013}}</ref><ref>{{cite web|last1=Malm|first1=William|last2=Olsson|first2=Rebecca|title=Floorball – The Future Sport|url=http://www.freeway.org/issue4/sports/floorball.htm|website=www.freeway.org|access-date=7 September 2016|archive-url=https://web.archive.org/web/20130316062621/http://www.freeway.org/issue4/sports/floorball.htm|archive-date=16 March 2013|date=1998|url-status=dead}}</ref><ref>{{cite web |url=http://www.floorballcentral.org/2010/01/true-history-of-floorball.html |title=The True History of Floorball |website=www.floorballcentral.org |date=16 January 2010 |access-date=7 September 2016 |archive-url=https://web.archive.org/web/20160910115136/http://www.floorballcentral.org/2010/01/true-history-of-floorball.html |archive-date=10 September 2016 |url-status=dead }}</ref> The sport began as something that was played for fun as a pastime in schools.<ref name="floorballnation1"/> After a decade or so, floorball began showing up in [[Nordic countries]] where the former schoolyard pastime was becoming a developed sport. Formal rules were soon developed, and clubs began to form. After some time, several countries developed national associations, and the IFF was founded in 1986.

=== Expansion ===
[[File:SCD - SSV.jpg|thumb|Floorball match in 1990]]
{{Main|List of IFF member nations}}

When the IFF was founded in 1986, the sport was played mostly in the Nordic countries, several parts of the rest of Europe and Japan. By 1990, floorball was recognized in 7 countries, and by the time of the first European Floorball Championships in 1994, the number had risen to 14. That number included the [[United States Floorball Association|United States]], who was the first country outside Europe and Asia to recognize floorball.<ref name=ifftoday>{{cite web |url=https://floorball.sport/this-is-floorball/history-in-short/ |title=History in short – IFF |website=floorball.sport |access-date=26 January 2020 |archive-date=4 April 2020 |archive-url=https://web.archive.org/web/20200404050531/https://floorball.sport/this-is-floorball/history-in-short/ |url-status=live }}</ref> By the time of the [[1996 Men's World Floorball Championships|first men's world championships]] in 1996, 20 nations played floorball, with 12 of them participating at the tournament.

Currently the IFF has 80 members, in addition to recognizing 11 other countries with ongoing floorball development.<ref>{{Cite web |title=Member Associations |url=https://floorball.sport/theiff/member-associations/ |access-date=2024-10-25 |website=IFF Main Site |language=en-GB}}</ref> Of its members, 58 have national floorball associations that are recognized by the IFF. With the addition of Sierra Leone, Africa's first floorball nation, the IFF has at least one national association on each continent of the world, with the exception of Antarctica.

=== Development ===
10 years after the IFF was founded, the first world championships were played, with a sold out final of 15,106 people at the [[Avicii Arena|Globen]] in [[Stockholm]], Sweden. In addition to that, the world's two largest floorball leagues, Finland's [[F-liiga|Salibandyliiga]] and Sweden's [[Swedish Super League (men's floorball)|Svenska Superligan]] were formed, in 1986 and 1995 respectively.

==== Recognition ====
In December 2008, the IFF and the sport of floorball received recognition from the [[International Olympic Committee]] (IOC). In July 2011, the IOC officially welcomed the IFF into its family of Recognised International Sports Federations (ARISF). This will pave the way for floorball to enter the official sport programme. The IFF hoped that this recognition would help allow floorball to become a part of the [[2020 Summer Olympics]].<ref>{{cite web |url=http://www.floorball.org/news.asp?tyyppi=vanhat&offset=20&kieli=826&id_tiedote=832&alue=171&yhteinen= |title=Floorball moves towards becoming an Olympic Sport |website=Floorball.org |date=12 December 2008 |access-date=7 September 2016|url-status=dead |archive-url=https://web.archive.org/web/20160305183240/http://www.floorball.org/news.asp?tyyppi=vanhat&offset=20&kieli=826&id_tiedote=832&alue=171&yhteinen= |archive-date=5 March 2016}}</ref> As of 2024, the IOC has not announced any plans to add floorball to future Olympic games.<ref>{{Cite news |last=Correspondent |first=Kimberly KwekSports |date=2023-12-05 |title=Floorball’s Olympic inclusion still a dream, but enhancements needed, says senior official |url=https://www.straitstimes.com/sport/olympic-inclusion-still-a-dream-but-floorball-needs-more-enhancements-first-says-senior-official |access-date=2024-10-25 |work=The Straits Times |language=en |issn=0585-3923}}</ref>

In January 2009, the IFF and the sport of floorball received recognition from the [[Special Olympics]].<ref>{{cite web |url=http://www.floorball.org/news.asp?kieli=826&id_tiedote=882&alue=171 |title=Floorball receives recognition by the Special Olympics |website=Floorball.org |date=23 January 2009 |access-date=7 September 2016|archive-url=https://web.archive.org/web/20160304235259/http://www.floorball.org/news.asp?kieli=826&id_tiedote=882&alue=171|archive-date=4 March 2016|url-status=dead}}</ref>

In addition to recognition by the IOC and Special Olympics, the IFF is also a member of the [[Global Association of International Sports Federations]] (GAISF, formerly SportAccord), and co-operates with the [[International University Sports Federation]] (FISU).<ref>{{cite web |url=https://floorball.sport/theiff/ |title=The IFF |website=floorball.sport |access-date=26 January 2020 |archive-date=4 April 2020 |archive-url=https://web.archive.org/web/20200404060649/https://floorball.sport/theiff/ |url-status=live }}</ref> Floorball is now also member of IWGA, which runs the [[World Games]], and floorball was on the programme for the first time in [[2017 World Games|Wrocław 2017]].

== Rules ==
{{Update|section|date=September 2023}}
Each team can field six players at a time on the court, one player being a [[#Goalkeepers|goalkeeper]]. But the [[Coach (sport)|coach]] can take the goalkeeper off and substitute them for a field player whenever they like, although it usually only happens in the end to increase the chances of scoring with one more outfield player. This can bring an advantage for the attacking side of the team but also disadvantages when it comes to their own defense. Both teams are also allowed to change players any time in the game; usually, a change comprises the whole team. Individual substitution happens sometimes, but usually only when a player is exhausted or hurt.

A floorball game is officially played over three periods lasting 20 minutes each (15 minutes for juniors). The clock is stopped in the case of penalties, goals, time-outs and any situation where the ball is not considered to be in play. The signal of a timeout is a triple honking sound.<ref name="IFF">{{cite web |date=1 July 2018 |title=Rules of the Game |url=https://floorball.sport/rules-and-regulations/rules-of-the-game/ |url-status=live |archive-url=https://web.archive.org/web/20200126184313/https://floorball.sport/rules-and-regulations/rules-of-the-game/ |archive-date=26 January 2020 |access-date=26 January 2020 |website=floorball.sport}}</ref> An intermission of 10 minutes (or maximum 15 minutes in some competitions)<ref name="IFF" /> takes place between each period, where teams change ends and substitution areas. Each team is allowed one timeout of 30 seconds, which is often used late in matches. There are two [[referee]]s to oversee the game, each with equal authority. If a game ends in a tie, teams play ten minutes extra, and the team that scores first wins.<ref name="IFF" /> If the game is still drawn after extra-time, a penalty shootout similar to ice-hockey decides the winner.

[[Checking (ice hockey)|Checking]] is prohibited in floorball. Controlled shoulder-to-shoulder contact is allowed but [[ice hockey]]-like checking is forbidden. Pushing players without the ball or competing for a loose ball is also disallowed, and many of these infractions lead to two-minute [[penalty (ice hockey)|penalties]]. The best comparison in terms of legal physical contact is [[Association football]] (soccer), where checking is used to improve one's positioning in relation to the ball rather than to remove an opposing player from the play. In addition to checking, players cannot lift an opponent's stick or perform any stick infractions in order to get to the ball. Moreover, players may not raise their stick or play the ball above knee level, and a stick may not be placed in between a player's legs. Passing the ball by foot is allowed more than once, following a rule change from 2022. Passing by hand or head deliberately may result in a two minutes penalty for the offending player. A field player may not enter the marked goal area and playing without stick is prohibited.

When a player commits a foul or when the ball is deemed unplayable, play is resumed from a free hit or a [[face-off]]. A free hit means that a player from one of the teams restarts the play from the place where the ball was last deemed unplayable. A comparable situation to this is a free kick in association football. For many fouls, such as stick infractions, a free hit is the only disciplinary action prescribed. However, at the referee's discretion, a two- or five-minute penalty may be assessed to the offending player. In that case, the player who committed the foul has to leave the field and sit out the punishment in a dedicated penalty area, leaving the player's team shorthanded for the time of the penalty. If an 'extreme' foul is committed, such as physical contact or unsportsmanlike conduct, a player may receive a 10-minute personal penalty.

=== Penalties ===
[[File:WFC2022 Slovakia vs Poland B 14.jpg|thumb|Referee indicating a penalty]]
{{Update|section|date=September 2023}}

Two-minute penalties can arise from a number of infractions and result in the offending player being sat on a penalty seat next to the scorers/timekeepers and away from the team benches. Each penalty has a specific code that is recorded on the [http://www.floorball.org/Liitetiedostot/IFF%20Match%20Record%202010.pdf official match record] along with the time of the foul. The team of the offending player will play short-handed for the full length of the penalty. The codes are as follows;

Two Minute Penalties
* 201: Hit
* 202: Blocking Stick
* 203: Lifting Stick
* 204: Incorrect Kick
* 205: High Kick
* 206: High Stick
* 207: Incorrect Push
* 208: Tackle/Trip
* 209: Holding
* 210: Obstruction
* 211: Incorrect Distance
* 212: Lying Play
* 213: Hands
* 214: Header
* 215: Incorrect Substitution
* 216: Too Many Players
* 217: Repeated Offences
* 218: Delaying
* 219: Protest
* 220: Incorrect Entering of the Rink
* 221: Incorrect Equipment
* 222: Measuring Stick
* 223: Incorrect Numbering
* 224: Play without Stick
* 225: Non-removal of Broken Stick
* 226: Penalty at Penalty Shot

2+2 Minute Penalties
* 501: Violent Hit
* 502: Dangerous Play
* 503: Hooking
* 504: Roughing
* 505: Repeated Offences

Personal Fouls/Penalties
* 101: Unsportsmanlike Conduct

Match Penalties
* 301: Technical Match Penalty
* 302: Match Penalty

=== Rink ===
[[File:Floorball rink.svg|thumb|230px|The dimensions of a floorball rink]]Floorball is played indoors on a rink whose size can officially vary from {{convert|18|–|20|m|ft|abbr=on}} wide to {{convert|36|–|40|m|ft|abbr=on}} long,<ref name="IFF" /> and which is surrounded by {{cvt|50|cm}} high enclosed boards with rounded corners. The goals are {{cvt|160|cm}} wide and {{cvt|115|cm}} high. Their depth is {{cvt|65|cm}} and they are {{cvt|2.85|m}} from the end of the nearest boards. Face-off dots are marked on the center line. Dots are also marked {{cvt|1.5|m}} from both sides of the rink on the goal lines imaginary extensions. The dots do not exceed {{cvt|30|cm}} in diameter. They do not have to be dots, they can also be crosses.<ref name="IFF" />

=== Equipment ===
[[File:WFC2022 Final Sweden vs Czech Republic F 67.jpg|right|thumb|Floorball stick blade that is held on the left side]]
Typical equipment for a floorball player consists of a stick, a pair of shorts, a shirt, socks, and indoor sport shoes. Players may wear [[shin guard]]s, eye protectors and protective padding for vital areas although most do not. Protective eyewear is, in some countries, compulsory for junior players.

A floorball stick is short compared with one for ice hockey; the maximum size for a stick is {{Convert|114|cm|abbr=on}}. As a stick cannot weigh any more than {{Convert|350|g}}, floorball sticks are often made of carbon and composite materials. The blade of the stick can either be "right" or "left" which indicates which way stick is supposed to be held from the player's point of view. A player who is right-handed will often use a "left" blade since they will be holding the stick to right, and the other way around for left-handed people.<ref>{{Cite web |title=Stick holding and posture in floorball |url=https://www.activesgcircle.gov.sg/learn/floorball/stick-holding-and-posture-in-floorball |access-date=9 September 2023}}</ref>

==== Goalkeepers ====
[[File:WFC2022 Final Sweden vs Czech Republic A 05.jpg|right|thumb|goal and goalkeeper]]
Goalkeepers wear limited protection provided by padded pants, a padded chest protector, knee pads and a helmet. Some goalkeepers like to wear gloves and/or wristbands The goalkeeper may also wear other protective equipment such as elbow pads and jock straps but bulky padding is not permitted. Goalkeepers do not use sticks and may use their hands to play the ball when they are within the goalkeeper's box. There, they are allowed to throw the ball out to their teammates provided that the ball touches the ground before the half court mark. They can assist but not score. When they are completely outside the box, goalkeepers are considered field players and are not allowed to touch the ball with their hands.

=== Ball ===
[[File:WFC2022 Slovakia vs Poland B 16.jpg|right|thumb|250px|A floorball ball. This is a plastic precision type ball, characterized by 1,516 tiny dimples that reduce air resistance, as well as friction on the floor.]]
A floor ball weighs {{cvt|23|g}} and its diameter is {{cvt|72|mm}}. It has 26 holes in it, each of which are {{cvt|10|mm}} in diameter. Many of these balls now are made with aerodynamic technology, where the ball has over a thousand small dimples in it that reduce air resistance. There have been several times where a ball has been recorded to have traveled at a speed of approximately {{convert|200|km/h|mph|abbr=on}}.<ref>{{cite web |date=5 November 2010 |title=New World Record |url=http://www.floorballcentral.org/2010/11/new-world-record.html |url-status=dead |archive-url=https://web.archive.org/web/20170506132124/http://www.floorballcentral.org/2010/11/new-world-record.html |archive-date=6 May 2017 |access-date=7 September 2016 |website=Floorballcentral.org}}</ref>

== Competitions ==


=== World championships ===
{{Main|Men's Floorball World Championships|Women's World Floorball Championship|List of World Floorball Champions}}
[[File:WFC2022 Finland vs Switzerland D 22.jpg|thumb|World Championships venue]]
[[File:Mika Kohonen 2013-04-05 (3).JPG|thumb|[[Mika Kohonen]], a Finnish floorball player and a four-time world champion in the sport,<ref>{{cite web |title=Mika Kohonen biography, Mika Kohonen achievements, Mika Kohonen career stats |url=http://www.edubilla.com/sport/floorball/players/mika-kohonen/ |url-status=live |archive-url=https://web.archive.org/web/20210204031844/http://www.edubilla.com/sport/floorball/players/mika-kohonen/ |archive-date=4 February 2021 |access-date=1 February 2021 |website=Edubilla.com}}</ref> was voted best floorball player in the world in 2005, 2009, 2010, 2011 and 2012.<ref>{{cite web |date=7 February 2013 |title=Världens bästa spelare 2012 – Mika Kohonen |trans-title=The world's best player 2012 – Mika Kohonen |url=https://innebandymagazinet.se/2013/02/07/varldens-basta-spelare-2012-mika-kohonen |url-status=live |archive-url=https://web.archive.org/web/20210205152832/https://innebandymagazinet.se/2013/02/07/varldens-basta-spelare-2012-mika-kohonen |archive-date=5 February 2021 |access-date=29 January 2021 |work=Innebandy Magzinet |language=sv}}</ref>]]
The world floorball championships is annual event, but each class only meet every other year—the men and women under 19 meet in even years, and the women and men under 19 meet in odd years. The Czech Republic, Finland, Norway, Sweden, and Switzerland remain the only five countries to have ever captured a medal at a World Championship event.
* The [[Men's World Floorball Championship]] takes place every December (since 2008) in every even year.
* The [[Women's World Floorball Championship]] takes place every December (since 2009) in every odd year.
* The [[Under-19 World Floorball Championships|Men's under-19 World Floorball Championship]] takes place every May (since 2009) in every odd year.
* The [[Under-19 World Floorball Championships|Women's under-19 World Floorball Championships]] takes place every May (since 2008) in every even year.

From 1996 to 2009, the IFF used a World Floorball Championship format where the last team in the A-Division was relegated to the B-Division, while the top team in the B-Division was promoted to the A-Division. This format caused much hardship for countries such as [[Men's national floorball team of Australia|Australia]], [[Men's national floorball team of Canada|Canada]], [[Men's national floorball team of Slovakia|Slovakia]], and [[Men's national floorball team of Spain|Spain]], who have all been trying to get to the B-Division from the C-Division since 2004. In 2010, the IFF adopted a [[FIFA]]-like continental qualification system, where teams must qualify to play at the world championships. Depending on the number of countries registered per continent or region, the IFF gives spots for the world championships. For example, [[Men's national floorball team of Argentina|Argentina]], [[Men's national floorball team of Brazil|Brazil]], [[Men's national floorball team of Canada|Canada]] and the [[Men's national floorball team of the United States|United States]] would need to play for one spot at the world championships in a continental qualification tournament for the Americas.<ref>{{cite web |title=WFC new style system |url=http://www.floorball.org/Liitetiedostot/CB2007_3_Appex%2014a%20WFC%20new%20system.pdf |url-status=live |archive-url=https://web.archive.org/web/20210922154239/http://www.floorball.org/Liitetiedostot/CB2007_3_Appex%2014a%20WFC%20new%20system.pdf |archive-date=22 September 2021 |access-date=27 January 2020 |website=floorball.org}}</ref>

In addition to the [[Men's World Floorball Championship|Floorball World Championships]], there are other IFF Events for club teams such as the [[Champions Cup (floorball)|Champions Cup]] which is for the national competition winners from the Top-4 [[IFF World Ranking|ranked nations]], and the EuroFloorball Cup for the national competition winners from the 5th and lower ranked nations. There are also many international floorball club competitions.

=== Asia Pacific Floorball Championship ===
{{Main|List of Asia Pacific Floorball champions}}
The Asia Pacific Floorball Championships are played every single year in New Zealand, Australia, Singapore, or Japan. The event was created by the [[Singapore Floorball Association]] together with the cooperation of the [[Asia Oceania Floorball Confederation]] (AOFC). Members of the AOFC get together during this tournament to play for the Asia Pacific Floorball Championship every year.

As of 2010, the Asia Pacific Floorball Championship is also the qualifying tournament for the [[World Floorball Championships]].

=== Canada Cup ===
{{Main|List of Canada Cup winners}}
The [[Canada Cup (floorball)|Canada Cup]] is an international club tournament that is held every year in [[Toronto]], [[Ontario]], Canada. It is the largest floorball club tournament outside of Europe, and attracts 55+ clubs from worldwide, every year.

=== Czech Open ===
{{Main|Czech Open (floorball)}}
The world's largest club team tournament, the [[Czech Open (floorball)|Czech Open]] is a traditional summer tournament held in Prague, Czech Republic. It is famous not only for its on-court activities, but also for those off-court. The tournament attracts 200+ clubs every year from 20 countries.

=== Champions Cup ===
{{Main|Champions Cup (floorball)|l1=Champions Cup}}
The Champions Cup was played for the first time in 2011. It is now the premier IFF event for Men's and Women's Club teams. The national championship winners from the Top-4 [[IFF World Ranking|ranked nations]] compete in the event.

=== EuroFloorball Cup ===
The EuroFloorball Cup (formerly European Cup) is an IFF-organised club event for both men's and women's teams. It has taken place every single year since 1993, and in 2000 it changed its format to a 2-year event (i.e. 2000–01). In 2008, the tournament switched back to its one-year format. In 2011 it underwent another change when the [[Champions Cup (floorball)|Champions Cup]] was introduced for the first time.

The EuroFloorball Cup (EFC) is now for the national competition winners from the 5th and lower ranked nations. Qualification can be made via a number of processes. Firstly, the teams from the 5th, 6th & 7th ranked nations receive automatic qualification. A team nominated by the local event organiser also gets automatic qualification, and then the last two spots are determined by qualification tournaments.

=== North American Floorball League ===
{{Main|North American Floorball League}}
The North American Floorball League is the first and only semi professional floorball league outside of Europe. It is not affiliated with any federation, so it has players from around the world. The inaugural set of teams are entirely based in the United States, though there is potential for expansion into Canada.

== Variations ==

=== 3v3 ===
This modality works almost the same as the normal 5v5 one, but with only 3 field players per team. Goalkeepers have a bag full of balls behind the goal, and they will play one if the current ball goes out the field. They can score directly if the ball bounces before the midfield line. Game time is divided in 2 parts of 10 minutes each with semi-effective time (only stops on goals or interruptions led by the referee) and a 2-minute break.

First 3vs3 World Floorball Championships were celebrated in [[Lahti]] (11-12 May 2024) with Finland winning the female tournament and Latvia doing the same in the male category. This WFC format is expected to be celebrated each year.
<ref>{{cite web |title=Home |url=https://floorball.sport/3v3wfc2024/}}</ref>

=== Freebandy ===
Freebandy is a sport that developed in the 2000s from floorball fanatics who specialize in a technique called "zorro", which involves lifting the ball onto a stick and allowing air resistance and fast movements to keep the ball "stuck" to the stick. This technique is also referred to as "airhooking" or "skyhooking". In freebandy, the rules are very much the same of those of floorball, with the exception of high nets and no infractions for high sticking. As well, the sticks are slightly tweaked from those of a floorball variety to include a "pocket" where the ball can be placed.

=== Special Olympics ===
Floorball at the Special Olympics is slightly modified from the "regular" form of floorball. Matches are played 3-on-3 with a goaltender, on a smaller court that measures {{convert|20|m|ft}} long by {{convert|12|m|ft}} wide. This form of floorball was developed for the intellectually disabled, and has yet to be played at the Special Olympics. Floorball was played as a demonstration sport at the [[2013 Special Olympics World Winter Games]],<ref>{{cite web |title=Special Olympics: Floorball |url=https://www.specialolympics.org/what-we-do/sports/floorball |url-status=live |archive-url=https://web.archive.org/web/20220515184046/https://www.specialolympics.org/what-we-do/sports/floorball |archive-date=15 May 2022 |access-date=7 September 2016 |website=Specialolympics.org}}</ref> and was played as an official sport at the [[2017 Special Olympics World Winter Games|games in 2017]].<ref>{{cite web |author=Mariusz Damentko |date=14 May 2014 |title=Special Olympics: Floorball is now an official Special Olympics World Games Sport |url=http://www.specialolympics.org/Stories/General/Floorball_is_now_an_official_Special_Olympics_World_Games_Sport.aspx |url-status=dead |archive-url=https://web.archive.org/web/20180729013030/http://www.specialolympics.org/Stories/General/Floorball_is_now_an_official_Special_Olympics_World_Games_Sport.aspx |archive-date=29 July 2018 |access-date=7 September 2016 |website=Specialolympics.org}}</ref>

=== Streetbandy ===
[[File:Katusählyä IMG 8429 C.JPG|thumb|Street Floorball Tournament was arranged on [[Helsinki]], Finland]]
A simplified less formal version of floorball, played with smaller team numbers and shorter periods, and typically outdoors on various surfaces, including AstroTurf. In its most basic form, it is an informal pick up game amongst friends. However, a more formal version is played in Sweden, with the following structure:<ref>{{cite web |title=Streetbandy |url=http://streetgames.se/om-street-games/streetbandy/ |url-status=dead |archive-url=https://web.archive.org/web/20160917175326/http://streetgames.se/om-street-games/streetbandy/ |archive-date=17 September 2016 |access-date=7 September 2016 |website=Streetgames.se |language=sv}}</ref>
* three field players on each team, with smaller overall team sizes (including subs.)
* small goals, with no goalie
* smaller playing area, usually closer to a half rink.
* 10-minute length.
* tendency towards "first team to score 5 goals in the time limit" rather than traditional scoring. Sudden death on a draw.
* penalties are taken from the centre line.
* most situations arising from the ball leaving play are resumed from a fixed point (e.g. corner, centre line)
* no physical contact, high sticks or dangerous activity allowed.

=== Swiss floorball ===
Swiss floorball called unihockey is a revised version of a floorball match. The match is played on a slightly smaller court and often involves only three field players playing on each side, in 3-on-3 floorball. This form of floorball is also slightly shorter, with only two periods of 15 to 20 minutes each played. In Switzerland this form of playing is called "smallcourt" (Kleinfeld), opposed to the usual style of playing on a bigger court, which is called "bigcourt" (Grossfeld).

=== Wheelchair floorball ===
[[File:WFC2022 Finland vs Switzerland Wheelchair Floorball 01.jpg|thumb|Wheelchair floorball game]]
Originally developed for players with disabilities, wheelchair floorball is played with exactly the same rules as "regular" floorball. Players use the same stick and ball, and goaltenders are also allowed to play.

The first ever IFF-sanctioned wheelchair floorball matches were played between the men's teams of the Czech Republic and Sweden during the [[2008 Men's World Floorball Championships]] in [[Prague]].

In addition to this, there is also an electric wheelchair variation.<ref>{{Cite web |title=Powerchair Hockey Floorball |url=https://floorball.sport/this-is-floorball/parafloorball/powerchair-hockey-floorball/ |url-status=live |archive-url=https://web.archive.org/web/20230130051504/https://floorball.sport/this-is-floorball/parafloorball/powerchair-hockey-floorball/ |archive-date=30 January 2023 |access-date=30 January 2023 |website=IFF Main Site |language=en-GB}}</ref>

== See also ==
* [[Indoor hockey]]
* [[Floor hockey]]
* [[Field hockey]]

== Notes and references ==
{{Reflist|30em}}

== External links ==
{{Commons category|Floorball}}
* [https://floorball.sport/ International Floorball Federation]

{{IFF Member Nations}}
{{National floorball teams}}
{{Team Sport}}
{{Sports of the World Games program}}
{{Authority control}}

[[Category:Floorball| ]]
[[Category:Team sports]]
[[Category:Indoor sports]]
[[Category:Ball games]]
[[Category:Variations of hockey]]
[[Category:Sports originating in Sweden]]
[[Category:Mixed-sex team sports]]
[[Category:Stick sports]]
[[Category:1960s establishments in Sweden]]

Aircraft

2025-07-14T17:21:48Z

45.232.105.68: /* Rotorcraft */

{{short description|Vehicle or machine that is able to fly by gaining support from the air}}
{{Use dmy dates|date=January 2025}}
[[File:Cessna 172S Skyhawk ‘G-JMKE’ (45077563364).jpg|thumb|The [[Cessna 172 Skyhawk]] is the [[List of most-produced aircraft|most produced aircraft]] in history.]]
[[File:RAN squirrel helicopter at melb GP 08.jpg|thumb|A [[Eurocopter AS350 Écureuil]] [[helicopter]].]]

An '''aircraft''' ({{plural form}} aircraft) is a [[vehicle]] that is able to [[flight|fly]] by gaining support from the [[Atmosphere of Earth|air]]. It counters the force of gravity by using either [[Buoyancy|static lift]] or the [[Lift (force)|dynamic lift]] of an [[airfoil]],<ref>{{Cite web|url=http://dictionary.reference.com/browse/aircraft|title=Aircraft — Define Aircraft at Dictionary.com|work=Dictionary.com|access-date=1 April 2015|url-status=live|archive-url=https://web.archive.org/web/20150328141634/http://dictionary.reference.com/browse/aircraft|archive-date=28 March 2015}}</ref> or, in a few cases, direct [[Powered lift|downward thrust]] from its engines. Common examples of aircraft include [[airplane]]s, [[rotorcraft]] (including [[helicopter]]s), [[airship]]s (including [[blimp]]s), [[Glider (aircraft)|gliders]], [[Powered paragliding|paramotors]], and [[hot air balloon]]s.<ref name="wingsoverkansas">{{Cite web|title=Different Kinds & Types of Aircraft|url=http://www.wingsoverkansas.com/features/a1037/|website=wingsoverkansas.com|url-status=live|archive-url=https://web.archive.org/web/20161121165354/http://www.wingsoverkansas.com/features/a1037/|archive-date=21 November 2016}}</ref> Part 1<ref>{{cite web | url=https://www.ecfr.gov/current/title-14/chapter-I/subchapter-A/part-1 | title=14 CFR Part 1 -- Definitions and Abbreviations }}</ref> (Definitions and Abbreviations) of Subchapter A of Chapter I of Title 14 of the U. S. Code of Federal Regulations states that aircraft "means a device that is used or intended to be used for flight in the air."

The human activity that surrounds aircraft is called ''[[aviation]]''. The science of aviation, including designing and building aircraft, is called ''[[aeronautics]].'' [[Aircrew|Crewed]] aircraft are flown by an onboard [[Aircraft pilot|pilot]], whereas [[unmanned aerial vehicle]]s may be remotely controlled or self-controlled by onboard [[computer]]s. Aircraft may be classified by different criteria, such as lift type, [[Powered aircraft#Methods of propulsion|aircraft propulsion]] (if any), usage and others.

== History ==
{{More citations needed section|date=April 2025}}
{{Main|History of aviation}}
{{See also|Timeline of aviation}}
[[File:Aviation (Nouveaau Larousse,c. 1900) DSCN2832.jpg|thumb|alt=An illustration showcasing various 19th-century aviation prototypes and designs.|Aviation in 19th century]]
The history of aviation spans over two millennia, from the earliest innovations like [[kite]]s and attempts at tower jumping to [[Supersonic speed|supersonic]] and [[hypersonic flight]] in powered, [[heavier-than-air flight|heavier-than-air]] [[jet aircraft]]. Kite flying in China, dating back several hundred years BC, is considered the earliest example of man-made flight.<ref name=":4">{{Cite web |title=Kite {{!}} Aeronautics, History & Benefits |url=https://www.britannica.com/topic/kite-aeronautics |access-date=2024-12-05 |website=www.britannica.com |language=en}}</ref> In the 15th century, [[Leonardo da Vinci]] created flying machine designs incorporating aeronautical concepts, but they were unworkable due to the limitations of contemporary knowledge.<ref>{{Cite journal |last=Botelho Parra |first=Rogerio |date=14 September 2018 |title=Leonardo da Vinci Interdisciplinarity |url=https://www.icas.org/icas_archive/ICAS2018/data/papers/ICAS2018_0301_paper.pdf |journal=31st Congress of the International Council of the Aeronautical Sciences |volume=1 |issue=1 |pages=10 |via=ICAS}}</ref>

In the late 18th century, the [[Montgolfier brothers]] invented the [[Hot air balloon|hot-air balloon]] which soon led to manned flights. At almost the same time, the discovery of [[hydrogen]] gas led to the invention of the [[hydrogen balloon]].<ref name="wings-tom">{{cite book |last1=Crouch |first1=Tom |title=Wings: A History of Aviation from Kites to the Space Age |publisher=W.W. Norton & Co |year=2004 |location=New York, New York |isbn=0-393-32620-9}}</ref> Various theories in [[mechanics]] by physicists during the same period, such as [[fluid dynamics]] and [[Newton's laws of motion]], led to the development of modern [[aerodynamics]]; most notably by [[Sir George Cayley]]. Balloons, both free-flying and tethered, began to be used for military purposes from the end of the 18th century, with France establishing balloon companies during the [[French Revolution]].<ref name="hallion">Hallion (2003)</ref>

In the 19th century, especially the second half, experiments with gliders provided the basis for learning the dynamics of winged aircraft; most notably by Cayley, [[Otto Lilienthal]], and [[Octave Chanute]]. By the early 20th century, advances in engine technology and aerodynamics made controlled, powered, manned heavier-than-air flight possible for the first time. In 1903, following their pioneering research and experiments with wing design and aircraft control, the [[Wright brothers]] successfully incorporated all of the required elements to create and fly the first airplane.<ref>[http://news.bbc.co.uk/2/hi/special_report/1998/11/98/great_balloon_challenge/299568.stm "Flying through the ages"] {{Webarchive|url=https://web.archive.org/web/20141021044458/http://news.bbc.co.uk/2/hi/special_report/1998/11/98/great_balloon_challenge/299568.stm |date=21 October 2014 }} ''BBC News''. Retrieved 2024-10-18.</ref> In 1906 [[Charles Frederick Page]] was granted the first U.S. patent for an aircraft.<ref>{{cite news |title=Louisiana figures fly out of aviation history |url=https://www.newspapers.com/article/the-times-louisiana-figures-fly-out-of-a/154560643/ |access-date=18 May 2025 |work=The Times |date=1 August 2020 |pages=A1}}</ref> The basic configuration with its characteristic [[cruciform tail]] was established by 1909, followed by rapid design and performance improvements aided by the development of more powerful engines.

The first vessels of the air were the rigid steerable balloons pioneered by [[Ferdinand von Zeppelin]] that became synonymous with [[airship]]s and dominated long-distance flight until the 1930s, when large [[flying boat]]s became popular for trans-oceanic routes. After [[World War II]], the flying boats were in turn replaced by airplanes operating from land, made far more capable first by improved [[propeller engine]]s, then by [[jet engine]]s, which revolutionized both civilian air travel and [[military aviation]].

In the latter half of the 20th century, the development of [[digital electronics]] led to major advances in flight instrumentation and "[[fly-by-wire]]" systems. The 21st century has seen the widespread use of [[pilotless drone]]s for military, commercial, and recreational purposes. With computerized controls, inherently unstable aircraft designs, such as [[flying wing]]s, have also become practical.

== Methods of lift ==
=== Lighter-than-air ===
{{Main|Aerostat}}
[[File:Colorado Springs Hot Air Balloon Competition.jpg|thumb|Hot air [[Balloon (aeronautics)|balloons]]]]
[[File:USS Akron (ZRS-4) in flight over Manhattan, circa 1931-1933.jpg|thumb|Airship [[USS Akron|USS ''Akron'']] over Manhattan in the 1930s]]
Lighter-than-air aircraft or ''[[aerostat]]s'' use [[buoyancy]] to float in the air in much the same way that ships float on the water. They are characterized by one or more large cells or canopies, filled with a [[lifting gas]] such as [[helium]], [[hydrogen]] or [[Hot air balloon|hot air]], which is less [[Density|dense]] than the surrounding air. Other gases lighter than air also theoretically work, however, such gases also needs to be same for human use (non-flammable, non-toxic).<ref>{{Cite web |date=2022-01-12 |title=What Is a Lifting Gas? - National Aviation Academy |url=https://www.naa.edu/lifting-gas/ |access-date=2025-04-26 |language=en-US}}</ref>

Small hot-air balloons, called [[sky lantern]]s, were first invented in ancient China prior to the 3rd century BC and used primarily in cultural celebrations, although they also had military purposes.<ref>{{Cite web |date=26 May 2024 |title=The Fascinating History of Hot Air Balloons: From Ancient Sky Lanterns to Modern Marvels |work=History Tools |url=https://www.historytools.org/stories/the-fascinating-history-of-hot-air-balloons-from-ancient-sky-lanterns-to-modern-marvels |access-date=26 April 2025}}</ref> They, along with [[kite]]s, were two forms of [[Unmanned aerial vehicle|unmanned]] aircraft that originated from China.<ref>{{Cite web |last=MAK |date=2025-01-22 |title=The Origin of Kites in Ancient China - CS Kites |url=https://cskites.com/blog/the-origin-of-kites-in-ancient-china/ |access-date=2025-04-26 |language=en-US}}</ref> Kites were also used in the military, but unlike sky lanterns, their flight is caused by the differences of air pressure beneath and above the kite.<ref>{{Cite web |last=Ashish |date=2016-08-02 |title=Why Is It Difficult To Fly Kites On Non-Windy Days? |url=https://www.scienceabc.com/pure-sciences/physics-kite-flying-how-to-make-aerodynamic-structure.html#:~:text=Kites%20fly%20because%20of%20the%20aerodynamic%20forces%20of,of%20the%20kite%20is%20balanced%20by%20the%20lift. |access-date=2025-04-26 |website=ScienceABC |language=en-US}}</ref>

A [[balloon (aeronautics)|balloon]] was originally any aerostat, while the term [[airship]] was used for large, powered aircraft designs — usually fixed-wing.<ref>[https://texashistory.unt.edu/ark:/67531/metapth172915/ US patent 467069] {{Webarchive|url=https://web.archive.org/web/20140223070653/http://texashistory.unt.edu/ark%3A/67531/metapth172915/ |date=23 February 2014}} "Air-ship" referring to a compound aerostat/rotorcraft.</ref><ref>[[Ezekiel Airship]] (1902) [http://www.wright-brothers.org/History_Wing/History_of_the_Airplane/History_of_the_Airplane_Intro/History_of_the_Airplane_Intro.htm wright-brothers.org] {{Webarchive|url=https://web.archive.org/web/20131203131729/http://www.wright-brothers.org/History_Wing/History_of_the_Airplane/History_of_the_Airplane_Intro/History_of_the_Airplane_Intro.htm |date=3 December 2013}}[http://altereddimensions.net/2012/burrell-cannon-flies-first-airplane altereddimensions.net] {{Webarchive|url=https://web.archive.org/web/20140222065900/http://altereddimensions.net/2012/burrell-cannon-flies-first-airplane |date=22 February 2014}} "airship," – referring to an HTA aeroplane.</ref><ref>[http://gustavewhitehead.org/news_journalism/1901_-_flying.html The Bridgeport Herald, August 18, 1901] {{Webarchive|url=https://web.archive.org/web/20130803021718/http://gustavewhitehead.org/news_journalism/1901_-_flying.html |date=3 August 2013}} – "air ship" referring to Whitehead's aeroplane.</ref><ref>Cooley Airship of 1910, also called the Cooley monoplane.{{Cite web|url=http://www.wright-brothers.org/History_Wing/Aviations_Attic/UFOs/UFOs.htm|title=Unbelievable Flying Objects|access-date=10 February 2014|url-status=live|archive-url=https://web.archive.org/web/20131102031147/http://www.wright-brothers.org/History_Wing/Aviations_Attic/UFOs/UFOs.htm|archive-date=2 November 2013}}{{Cite web|url=https://www.xpolet.eu.org|title=Round Aircraft Designs|access-date=7 September 2011|url-status=dead|archive-url=https://web.archive.org/web/20120402075442/http://celticowboy.com/Round%20Aircraft%20Designs.htm|archive-date=2 April 2012}} – a heavier-than-air monoplane.</ref><ref>Frater, A.; ''The Balloon Factory'', Picador (2009), p. 163. Wright brothers' "airship."</ref><ref>[http://www.technovelgy.com/ct/content.asp?Bnum=879 George Griffith, ''The angel of the Revolution'', 1893] {{Webarchive|url=https://web.archive.org/web/20140222154830/http://www.technovelgy.com/ct/content.asp?Bnum=879 |date=22 February 2014}} — "air-ship," "vessel" referring to a VTOL compound rotorcraft (not clear from the reference if it might be an aerostat hybrid.)</ref> In 1919, [[Frederick Handley Page]] was reported as referring to "ships of the air," with smaller passenger types as "Air yachts."<ref>[http://paperspast.natlib.govt.nz/cgi-bin/paperspast?a=d&d=AS19190224.2.104 Auckland Star, 24 February 1919] {{Webarchive|url=https://web.archive.org/web/20140324163806/http://paperspast.natlib.govt.nz/cgi-bin/paperspast?a=d&d=AS19190224.2.104 |date=24 March 2014}} "Ships of the air," "Air yachts" – passenger landplanes large and small</ref> In the 1930s, large intercontinental flying boats were also sometimes referred to as "ships of the air" or "flying-ships".<ref>[https://nla.gov.au/nla.news-article17455790 The Sydney Morning Herald, Monday 11 April 1938] – "ship of the airs," "flying-ship," referring to a large flying-boat.</ref><ref>[http://airandspace.si.edu/exhibitions/america-by-air/online/innovation/innovation16.cfm Smithsonian, America by air] {{Webarchive|url=https://web.archive.org/web/20140118135217/http://airandspace.si.edu/exhibitions/america-by-air/online/innovation/innovation16.cfm |date=18 January 2014}} "Ships of the Air" referring to Pan Am's Boeing Clipper flying-boat fleet.</ref>

Lighter-than-air aircraft don't typically require a pilot's license in the United States.<ref>{{Cite web |last=Altmann |first=Ray |date=2025-03-01 |title=Ultralight Aircraft: Planes You Can Fly Without a Pilot License |url=https://epicflightacademy.com/ultralight-aircraft/ |access-date=2025-06-15 |website=Epic Flight Academy |language=en-US}}</ref> In most countries in Europe, standards for flying Lighter-than-air aircraft tend to be stricter compared to the United States.<ref>Balloon and other aircraft certifications or regulations. https://www.easa.europa.eu/en/regulations#regulations-balloons</ref>

=== Heavier-than-air{{Anchor|Heavier than air}} ===
Heavier-than-air aircraft or ''aerodynes'' are denser than air and thus must find some way to obtain enough [[Lift (physics)|lift]] that can overcome the aircraft's weight. There are two ways to produce dynamic upthrust — [[aerodynamic lift]] by having air flowing past an [[aerofoil]] (such dynamic interaction of aerofoils with air is the origin of the term "aerodyne"), or [[powered lift]] in the form of [[Reaction (physics)|reactional]] lift from downward engine [[thrust]].<ref name=":0">{{Cite web |last=Laurent |date=2023-11-15 |title=Understanding the Aerodynamic Forces in Flight |url=https://www.studyflight.com/understanding-the-aerodynamic-forces-in-flight/ |access-date=2025-04-26 |website=Study flight |language=fr-FR}}</ref><ref>{{Cite web |date=13 May 2021 |title=Rocket Principles |url=https://www.grc.nasa.gov/WWW/k-12/rocket/TRCRocket/rocket_principles.html |access-date=26 April 2025 |website=NASA}}</ref>

Aerodynamic lift involving [[wing]]s is the most common, and can be achieved via two methods. [[Fixed-wing aircraft]] ([[airplane]]s and [[Glider (aircraft)|gliders]]) achieve airflow past the wings by having the entire aircraft moving forward through the air, while [[rotorcraft]] ([[helicopter]]s and [[autogyro]]s) do so by having [[Rotor wing|mobile, elongated wings]] spinning rapidly around a mast in an assembly known as the [[Helicopter rotor|rotor]].<ref>{{Cite web |date=2021-12-20 |title=2.1.2: Rotorcraft |url=https://eng.libretexts.org/Bookshelves/Aerospace_Engineering/Fundamentals_of_Aerospace_Engineering_(Arnedo)/02:_Generalities/2.01:_Classification_of_aerospace_vehicles/2.1.02:_Rotorcraft |access-date=2025-04-26 |website=Engineering LibreTexts |language=en}}</ref><ref name=":0" />

==== Fixed-wing Aircraft ====
{{Main|Fixed-wing aircraft}}
[[Glider (sailplane)|Gliders]] were one of the first forms of a fixed wing aircraft. They are a special type of aircraft that doesn't require an engine.<ref>{{Cite news |title=Gliders {{!}} Glenn Research Center {{!}} NASA |url=https://www1.grc.nasa.gov/beginners-guide-to-aeronautics/gliders/ |archive-url=https://web.archive.org/web/20250308232351/https://www1.grc.nasa.gov/beginners-guide-to-aeronautics/gliders/ |archive-date=2025-03-08 |access-date=2025-04-26 |work=Glenn Research Center {{!}} NASA |language=en-US}}</ref> The first person to successfully build a human-carrying glider was [[George Cayley]], who also was the first to discover the four major aerodynamic forces.<ref>{{Cite web |title=The Pioneers : An Anthology : Sir George Cayley Bt. (1773 - 1857) |url=https://ctie.monash.edu.au/hargrave/cayley.html |access-date=2025-04-26 |website=ctie.monash.edu.au}}</ref> The first powered aircraft ([[Airplane]]) was invented by [[Wright brothers|Wilbur and Orville Wright]].<ref>{{Cite web |date=2003-12-01 |title=Who Invented the Airplane? (Grades K-4) - NASA |url=https://www.nasa.gov/learning-resources/for-kids-and-students/who-invented-the-airplane-grades-k-4/ |access-date=2025-04-26 |language=en-US}}</ref>

==== Rotorcraft ====
{{Main|Rotorcraft}}
[[File:Mil Mi-8P, Baltic Airlines (cropped).jpg|thumb|The [[Mil Mi-8]] is the most produced rotorcraft.]]
A ''rotary-wing aircraft'', ''rotorwing aircraft'' or ''rotorcraft'' is a heavier-than-air aircraft with [[Rotor wing|rotary wings]] that spin around a vertical mast to generate [[Lift (force)|lift]]. The assembly of several rotor blades mounted on a single mast is referred to as a [[Helicopter rotor|rotor]]. The [[International Civil Aviation Organization]] (ICAO) defines a rotorcraft as "supported in flight by the reactions of the air on one or more rotors".<ref>"ICAO Annex 7." Retrieved on 30 September 2009.</ref>

Rotorcraft generally include aircraft where one or more rotors provide lift throughout the entire flight, such as [[helicopter]]s, [[gyroplane]]s, [[autogyro]]s, and [[gyrodyne]]s Compound rotorcraft augment the rotor with additional thrust engines, propellers, or static lifting surfaces. Some types, such as helicopters, are capable of [[VTOL|vertical takeoff and landing]]. An aircraft which uses rotor lift for vertical flight but changes to solely fixed-wing lift in horizontal flight is not a rotorcraft but a [[convertiplane]].

==== Other methods of lift ====
{{Further|Lifting body}}

* A [[lifting body]] is an aircraft which produces lift through the shape of its body, rather than its wings or rotors, like conventional aircraft. Lifting bodies were first experimented by NASA in the 1960s-70s, but the idea was already conceived in the 1950s.<ref>{{Cite web |date=2014-02-28 |title=Lifting Bodies - NASA |url=https://www.nasa.gov/aeronautics/aircraft/lifting-bodies/ |access-date=2025-04-27 |language=en-US}}</ref>
* A [[powered lift]] aircraft is one which has the capability of vertical [[takeoff]] and [[landing]]. These aircraft must transition from vertical to lateral movement, which is considered the most dangerous phases of a flight.<ref>{{Cite web |title=Powered-Lift Aircraft {{!}} SKYbrary Aviation Safety |url=https://skybrary.aero/articles/powered-lift-aircraft |access-date=2025-04-27 |website=skybrary.aero}}</ref> Classes of powered lift types include [[VTOL]] jet aircraft (such as the [[Harrier jump jet]]) and [[tiltrotor]]s, such as the [[Bell Boeing V-22 Osprey]], among others.<ref>{{Cite web |last=Siminski |first=Jacek |date=2013-04-11 |title=Harrier: The Story Of The "Jump Jet" That Helped Margaret Thatcher Win The Falklands War |url=https://theaviationist.com/2013/04/11/harrier-story/ |access-date=2025-04-27 |website=The Aviationist |language=en-US}}</ref><ref>{{Cite web |title=V-22 Osprey |url=https://www.aviation.marines.mil/About/Aircraft/Tilt-Rotor/pubDate/20250423/ |access-date=27 April 2025 |website=Marines}}</ref>
* An [[ornithopter]] is an aircraft that produces lift through the movement of its wings, akin to how a bird flies.<ref>{{Cite news |date=2010-09-24 |title='World's first' ornithopter takes flight |url=https://www.bbc.com/news/world-us-canada-11410410 |access-date=2025-04-27 |work=BBC News |language=en-GB}}</ref>

== Size and speed extremes ==
=== Size ===
{{Main|List of large aircraft}}The largest aircraft by dimensions and volume (as of 2016) is the {{cvt|302|ft|m}} long British [[Airlander 10]], a hybrid blimp, with helicopter and fixed-wing features, and reportedly capable of speeds up to {{cvt|90|mph|km/h kn}}, and an airborne endurance of two weeks with a payload of up to {{cvt|22050|lbs|kg}}.<ref name="telegraph">[https://www.telegraph.co.uk/news/2016/08/17/worlds-largest-aircraft-the-airlander-takes-first-flight/ "World's largest aircraft the Airlander makes maiden flight in UK,"] {{Webarchive|url=https://web.archive.org/web/20161122224818/http://www.telegraph.co.uk/news/2016/08/17/worlds-largest-aircraft-the-airlander-takes-first-flight/ |date=22 November 2016}} 16 August 2016, London 'Daily Telegraph' via Telegraph.co.uk. Retrieved 22 November 2016.</ref><ref name="airlander_cbs">"Airlander 10, the world's largest aircraft, takes off for the first time," 19 August 2016, CBS News (TV) retrieved 22 November 2016.</ref><ref name="crash_cnn">Kottasova, Ivana [https://money.cnn.com/2016/08/24/technology/worlds-largest-aircraft-crash-airlander-10/ "The world's largest aircraft crashes after 2nd test flight"] {{Webarchive|url=https://web.archive.org/web/20161122224325/https://money.cnn.com/2016/08/24/technology/worlds-largest-aircraft-crash-airlander-10/ |date=22 November 2016}}, 24 August 2016, ''CNN Tech'' on [[CNN]], the Cable News Network. Retrieved 22 November 2016.</ref>

The largest aircraft by weight and largest regular fixed-wing aircraft ever built, {{as of|2016|lc=y}}, was the [[Antonov An-225 Mriya|Antonov An-225 ''Mriya'']]. That Soviet-built ([[Ukrainian SSR]]) six-engine transport of the 1980s was {{cvt|84|m|ft}} long, with an {{cvt|88|m|ft}} wingspan. It holds the world payload record, after transporting {{cvt|428834|lbs|kg}} of goods, and has flown {{cvt|100|t|lbs}} loads commercially. With a maximum loaded weight of {{cvt|550-700|t|lbs}}, it was also the heaviest aircraft built to date. It could cruise at {{cvt|500|mph|km/h kn}}.<ref>{{Cite web|last1=July|first1=Dyre|title=Fly Drive Aanbiedingen|url=https://www.flydrivereizen.nl/aanbiedingen/|website=flydrivereizen.nl|url-status=live|archive-url=https://web.archive.org/web/20161104014121/https://www.flydrivereizen.nl/aanbiedingen/|archive-date=4 November 2016}}</ref><ref name="biggest_fox">[https://www.foxnews.com/tech/watch-the-worlds-biggest-plane-land-in-australia/ "Watch the world's biggest plane land in Australia,"] 16 May 2016, Fox News. Retrieved 22 November 2016.</ref><ref name="biggest_chron">{{cite news|last=Rumbaugh|first=Andrea|url=http://www.chron.com/business/article/World-s-largest-airplane-lands-at-Bush-airport-10622046.php#item-38488|title=World's biggest airplane lands at Bush airport|archive-url=https://web.archive.org/web/20161123052928/http://www.chron.com/business/article/World-s-largest-airplane-lands-at-Bush-airport-10622046.php|archive-date=23 November 2016|date=18 November 2016|work=Houston Chronicle}}</ref><ref name="worlds_largest_might_lose_smithsonian_2015">Lewis, Danny, [http://www.smithsonianmag.com/smart-news/worlds-largest-aircraft-might-lose-its-title-blimp-180956677/ "The World's Largest Aircraft Might Lose its Title to a Blimp,"], 18 September 2015, ''Smart News'', Smithsonian.com, [[Smithsonian Institution]], Washington, D.C.. Retrieved 22 November 2016.</ref><ref name="largest_aero">[http://www.aerospaceweb.org/question/design/q0188.shtml "Ask Us – Largest Plane in the World,"] Aerospaceweb.org. Retrieved 22 November 2016.</ref> The aircraft was destroyed during the [[Russo-Ukrainian War]].<ref>{{Cite web|last=Shead|first=Sam|title=Photos show world's largest cargo plane destroyed in Ukraine|url=https://www.cnbc.com/2022/04/04/antonov-an-225-wreckage-worlds-largest-plane-destroyed-in-ukraine.html|access-date=25 January 2023|website=CNBC|date=4 April 2022}}</ref>

The largest military airplanes are the Ukrainian [[Antonov An-124 Ruslan|Antonov An-124 ''Ruslan'']] (world's second-largest airplane, also used as a civilian transport),<ref name="2nd_nasa">[https://www.nasa.gov/centers/glenn/multimedia/imagegallery/image_feature_028_Antonov.html "World's Second Largest Aircraft,"] {{Webarchive|url=https://web.archive.org/web/20161122222701/https://www.nasa.gov/centers/glenn/multimedia/imagegallery/image_feature_028_Antonov.html |date=22 November 2016}} 28 July 2013, [[NASA]]. Retrieved 22 November 2016.</ref> and American [[Lockheed C-5 Galaxy]] transport, weighing, loaded, over {{cvt|380|t|lbs}}.<ref name="largest_aero" /><ref name="wide_nasa">Loftin, Laurence K., Jr., [https://history.nasa.gov/SP-468/ch13-5.htm "Wide-Body Transports"] {{Webarchive|url=https://web.archive.org/web/20130607034616/http://history.nasa.gov/SP-468/ch13-5.htm |date=7 June 2013}}, in Chapter 13, "Jet Transports," in Part II, "The Jet Age," in ''Quest for Performance: The Evolution of Modern Aircraft'', NASA SP-468, 1985, Scientific and Technical Information Branch, [[NASA]], Washington, D.C., Updated: 6 August 2004. Retrieved 22 November 2016.</ref> The 8-engine, piston/propeller [[Hughes H-4 Hercules|Hughes H-4 ''Hercules'']] "Spruce Goose" — an American [[World War II]] wooden flying boat transport with a greater wingspan (94m/260 ft) than any current aircraft and a tail height equal to the tallest (Airbus A380-800 at 24.1m/78 ft) — flew only one short hop in the late 1940s and never flew out of [[Ground effect (aerodynamics)|ground effect]].<ref name="largest_aero" />

The largest civilian airplanes, apart from the above-noted An-225 and An-124, are the [[Airbus Beluga]] cargo transport derivative of the [[Airbus A300]] jet airliner, the [[Boeing Dreamlifter]] cargo transport derivative of the [[Boeing 747]] jet airliner/transport (the 747-200B was, at its creation in the 1960s, the heaviest aircraft ever built, with a maximum weight of over {{cvt|400|t|lbs}}),<ref name="wide_nasa" /> and the double-decker [[Airbus A380]] "super-jumbo" jet airliner (the world's largest passenger airliner).<ref name="largest_aero" /><ref name="airbus_times">[https://www.nytimes.com/2008/04/29/business/worldbusiness/29iht-airbus.4.12438349.html "Airbus reviews A380 schedule,"] {{Webarchive|url=https://web.archive.org/web/20170202002211/http://www.nytimes.com/2008/04/29/business/worldbusiness/29iht-airbus.4.12438349.html |date=2 February 2017}} 29 April 2008, ''[[The New York Times]]''. Retrieved 22 November 2016.</ref>

=== Speeds ===
{{Main|Flight airspeed record}}
The fastest fixed-wing aircraft and fastest glider, is the [[Space Shuttle]], which re-entered the atmosphere at nearly Mach 25 or {{cvt|17,500|mph|km/h}}<ref name="regimes">{{cite web|editor=Benson, Tom|url=https://www.grc.nasa.gov/WWW/BGH/hihyper.html|title=Speed Regimes: Hypersonic Re-Entry|archive-url=https://web.archive.org/web/20161123052843/https://www.grc.nasa.gov/WWW/BGH/hihyper.html|archive-date=23 November 2016|url-status=live|publisher=Glenn Research Center, [[NASA]]}}</ref>

The fastest recorded powered aircraft flight and fastest recorded aircraft flight of an air-breathing powered aircraft was of the [[NASA X-43]]A ''Pegasus'', a [[scramjet]]-powered, [[Hypersonic speed|hypersonic]], [[lifting body]] experimental research aircraft, at [[Mach number|Mach]] 9.68 or {{cvt|6,755|mph|sigfig=4}} on 16 November 2004.<ref>{{cite web|url=https://www.guinnessworldrecords.com/world-records/fastest-aircraft-air-breathing-engine|title=Fastest aircraft, air-breathing engine: X-43|date=16 November 2004|work=Guinness World Records}}</ref>

Prior to the X-43A, the fastest recorded powered airplane flight, and still the record for the fastest manned powered airplane, was the [[North American X-15]], rocket-powered airplane at Mach 6.7 or 7,274 km/h (4,520 mph) on 3 October 1967.<ref name="manned_guinness">{{cite web|url=https://www.guinnessworldrecords.com/world-records/78491-fastest-aircraft-rocket-powered|title=Fastest speed in a non-spacecraft aircraft|work=Guinness World Records|date=3 October 1967}}</ref>

The fastest manned, air-breathing powered airplane is the [[Lockheed SR-71 Blackbird]], a U.S. [[reconnaissance]] jet fixed-wing aircraft, having reached {{cvt|3529.56|km/h|adj=ri0|sigfig=4}} on 28 July 1976.<ref>{{cite web|url=https://www.fai.org/record/8879|date=28 July 1976|title=current record, Powered Aeroplanes, Absolute, Speed|publisher=[[Fédération Aéronautique Internationale|FAI]]}}</ref>

== Propulsion and steering ==
=== Unpowered aircraft ===
{{Main|Unpowered aircraft}}The main feature of unpowered aircraft is the inability to directly provide thrust through its engines. This means that all unpowered aircraft rely on the [[Wind|environment]] for sustained flight. Gliders, for example, take advantage of their aerodynamic properties to enable them to travel long distances. Techniques such as thermal circling, where gliders fly into warm air which allows them to rise, prolongs flight time.<ref>{{Cite web |title=Understanding the Principles of Glider Flight |url=https://physicscore.com/articles/principles-of-glider-flight/ |access-date=27 April 2025}}</ref>

Due to the lack of an engine, initial propulsion assistance is usually necessary to ensure flight. A common glider launching method is aerotowing, where another aircraft tows the glider to an altitude from which sustained flight is possible.<ref>{{Cite web |last=cwarrior |title=How Gliders Fly - Beverley Soaring Society - West Australia Gliding Club |url=https://www.beverley-soaring.org.au/about-gliding/how-gliders-fly/#:~:text=Unlike%20pelicans,%20glider%20wings%20don%E2%80%99t%20flap,%20so%20they,a%20ground-based%20winch%20and%20a%20very%20long%20cable. |access-date=2025-04-27 |website=Beverley Soaring Society |language=en-US}}</ref> Steering for a glider is also rudimentary, while more complex gliders like sailplanes usually have joysticks for steering, more basic aircraft like [[Hang gliding|hang gliders]] rely on the pilot's physical coordination to change the centre of gravity.<ref>{{Cite web |last=Team |first=Enviroliteracy |date=2025-04-21 |title=Can you steer a glider? |url=https://enviroliteracy.org/can-you-steer-a-glider/ |access-date=2025-04-27 |website=The Environmental Literacy Council |language=en-US}}</ref>[[File:PH-1274 Rolladen-Schneider LS-4b.JPG|thumb|Sailplane ([[Rolladen-Schneider LS4]])]]

=== Powered aircraft ===
{{Main|Aircraft engine}}
A powered aircraft is an aircraft with a source of mechanical power, used to produce thrust. Such sources are generally [[engine]]s, as is the case with airplanes, but can be human-powered in more extreme cases.<ref>{{Cite web |date=13 May 2021 |title=How does a jet engine work? |url=https://www.grc.nasa.gov/www/k-12/UEET/StudentSite/engines.html |access-date=27 April 2025 |website=NASA}}</ref><ref>{{Cite web |last=Paleja |first=Ameya |title=Human-powered aircraft: A plane with 'impossible engineering' and no engine |url=https://interestingengineering.com/innovation/lazarus-human-powered-aircraft?group=test_b |access-date=2025-04-27 |website=Interesting Engineering |language=en}}</ref>

==== Propeller aircraft ====
Propeller aircraft, as their name suggests, rely on propellers to produce thrust for the airplane.{{Citation needed|date=May 2025}}[[File:WestCoastAirFloatplane.jpg|thumb|A [[turboprop]]-engined [[De Havilland Canada DHC-6 Twin Otter|DeHavilland Twin Otter]] adapted as a [[floatplane]]]]

==== Jet aircraft ====
{{Main|Jet aircraft}}
[[File:Lockheed Martin F-22A Raptor JSOH.jpg|thumb| [[Lockheed Martin F-22 Raptor|Lockheed Martin F-22A Raptor]]]]

Compared to engines using propellers, jet engines can provide much higher thrust, higher speeds and, above about {{Convert|40000|ft|m|abbr=on}}, greater efficiency.<ref name="hist8">{{Cite web|url=http://www.hq.nasa.gov/pao/History/SP-468/ch10-3.htm|title=ch10-3|publisher=Hq.nasa.gov|access-date=26 March 2010|url-status=live|archive-url=https://web.archive.org/web/20100914184628/http://www.hq.nasa.gov/pao/History/SP-468/ch10-3.htm|archive-date=14 September 2010}}</ref>

==== Rotorcraft ====
{{Main|Rotorcraft}}{{Empty section|date=April 2025}}

== Design and construction ==
The key parts of an aircraft are generally divided into three categories:
* The ''structure'' ("[[airframe]]"<ref name="websters_3rd_new_intl_dictionary">Gove, P.B., editor: ''Webster's Third New International Dictionary of the English Language, Unabridged,'' 1993, Merriam-Webster, Springfield, Mass., USA</ref><ref name="asa_dictionary_3rd_ed">Crane, D., editor: ''Dictionary of Aeronautical Terms,'' Third Edition, ASA (Aviation Supplies & Academics), Newcastle, Washington, USA</ref><ref name="far_amt_2012_faa">''2012 Federal Aviation Regulations for Aviation Maintenance Technicians,'' 2012, Federal Aviation Administration, U.S. Department of Transportation</ref><ref name="janes_dictionary_1980">[[Bill Gunston|Gunston, Bill]], editor: ''Jane's Aerospace Dictionary'' 1980, Jane's, London / New York / Sydney</ref>) comprises the main load-bearing elements and associated equipment, as well as flight controls.
* The ''propulsion system'' ("[[powerplant]]"<ref name="websters_3rd_new_intl_dictionary" /><ref name="asa_dictionary_3rd_ed" /><ref name="phak_glossary_faa_gov">[https://www.faa.gov/regulations_policies/handbooks_manuals/aviation/phak/media/21_phak_glossary.pdf "Glossary"] in ''Pilot's Handbook of Aeronautical Knowledge'' (PHAK), [[Federal Aviation Administration]], Washington, D.C., retrieved 12 September 2022</ref>) (if it is powered) comprises the power source and associated equipment, as described above.
* The ''[[avionics]]'' comprise the electrical and electronic control, navigation and communication systems.<ref name="websters_3rd_new_intl_dictionary" /><ref name="asa_dictionary_3rd_ed" /><ref name="janes_dictionary_1980" /><ref name="dictionary_of_aviation_1974_fell">Wragg, David W. editor: ''A Dictionary of Aviation,'' 1974, Frederick Fell, New York</ref>

=== Structure ===
==== Aerostats ====
{{Main|Aerostat}}

[[File:OAM_Aerostat_TARS_Deming_New_Mexico_(16715553462).jpg|thumb|A modern aerostat used by the [[U.S. Department of Homeland Security]], the [[Tethered Aerostat Radar System]] (TARS)]]

An ''aerostat'' or ''lighter-than-air aircraft'' relies on [[buoyancy]] to maintain [[flight]]. Aerostats include unpowered [[balloon (aircraft)|balloon]]s (free-flying or [[moored balloon|tethered]]) and [[aircraft engine|powered]] [[airship]]s. The [[relative density]] of an aerostat as a whole is lower than that of the surrounding [[atmospheric]] [[air]] (hence the name "lighter-than-air"). Its main component is one or more gas capsules made of lightweight [[skin (aeronautics)|skin]]s, containing a [[lifting gas]] (hot air, or any gas with lower density than air, typically [[hydrogen]] or [[helium]]) that [[displacement (fluid)|displace]]s a large volume of air to generate enough buoyancy to overcome its own [[weight]]. [[Payload]] (passengers and cargo) can then be carried on attached components such as a [[basket]], a [[gondola (airship)|gondola]], a [[cabin (aircraft)|cabin]] or various [[hardpoint]]s.<ref>{{Cite book|url=https://books.google.com/books?id=pz2ORay2HWoC|title=The Chambers Dictionary|last=Chambers|first=Allied|date=1998|publisher=Allied Publishers|isbn=9788186062258|page=541|language=en|quote=the gas-bag of a balloon or airship}}</ref><ref>{{cite book |title=The Oxford Illustrated Dictionary |page=281 |publisher=Oxford University Press |year=1976 |orig-year=1975 |location=Great Britain |quote=fabric enclosing gas-bags of airship}}</ref> With airships, which need to be able to fly against wind, the lifting gas capsules are often protected by a more rigid outer envelope or an [[airframe]], with other gasbags such as [[ballonet]]s to help modulate buoyancy.

Aerostats are so named because they use [[aerostatic]] buoyant force that does not require any forward movement through the surrounding air mass, resulting in the inherent ability to [[levitation (physics)|levitate]] and perform [[vertical takeoff and landing]]. This contrasts with the heavier-than-air [[aircraft#Heavier-than-air|aerodyne]]s that primarily use [[aerodynamic]] [[lift (force)|lift]], which must have consistent airflow over an [[aerofoil]] ([[wing]]) surface to stay airborne. The term has also been used in a narrower sense, to refer to the statically [[tethered balloon]] in contrast to the free-flying airship.<ref>{{cite book |title=A Dictionary of Aviation |first=David W. |last=Wragg |isbn=9780850451634 |edition=first |publisher=Osprey |year=1973 |page=8}}</ref> This article uses the term in its broader sense.

==== Aerodynes ====
[[File:Merlin Airframe Material.jpg|thumb|Airframe diagram for an [[AgustaWestland AW101]] [[helicopter]]]]{{Empty section|date=March 2025}}

=== Power ===
{{Main|Propulsion}}
The source of motive power for an aircraft is normally called the ''[[powerplant]],'' and includes [[engine]] or [[motor]], [[propeller]] or [[Helicopter rotor|rotor]], (if any), [[jet nozzle]]s and [[thrust reverser]]s (if any), and accessories essential to the functioning of the engine or motor (e.g.: [[Starter motor|starter]], [[ignition system]], [[intake|intake system]], [[exhaust system]], [[Aircraft fuel system|fuel system]], [[lubrication]] system, [[engine cooling system]], and [[engine controls]]).<ref name="websters_3rd_new_intl_dictionary" /><ref name="asa_dictionary_3rd_ed" /><ref name="phak_glossary_faa_gov"/>

Powered aircraft are typically powered by [[internal combustion engine]]s ([[piston engine|piston]]<ref name="internal_combustion_engine_grc_nasa_gov">[https://www.grc.nasa.gov/www/k-12/airplane/icengine.html "Internal Combustion Engine,"] Glenn Research Center, [[National Aeronautics and Space Administration]] (NASA), retrieved 12 September 2022</ref> or [[gas turbine engine|turbine]]<ref name="engines_grc_nasa_gov">[https://www.grc.nasa.gov/www/k-12/airplane/icengine.html "Engines,"] Glenn Research Center, [[National Aeronautics and Space Administration]] (NASA), retrieved 12 September 2022</ref>) burning [[fossil fuels]]—typically [[gasoline]] ([[avgas]]) or [[jet fuel]]. A very few are powered by [[rocket engine|rocket power]], [[ramjet]] propulsion, or by [[electric motors]], or by internal combustion engines of other types, or using other fuels. A very few have been powered, for short flights, by [[human-powered aircraft|human muscle energy]] (e.g.: [[Gossamer Condor]]).<ref name="natl_air_and_space_museum_bryan">Bryan, C.D.B.: ''The National Air and Space Museum,'' 1979 / 1984, Abrams, New York</ref><ref name="janes_encyclopedia_of_aviation">Taylor, Michael J.H., editor: ''Jane's Encyclopedia of Aviation,'' 1989 ed., Portland House / Random House, New York</ref><ref name="electrified_aircraft_nasa_gov">[https://www1.grc.nasa.gov/aeronautics/eap/ "Electrified Aircraft Propulsion" (EAP)], Glenn Research Center, [[National Aeronautics and Space Administration]] (NASA), retrieved 12 September 2022</ref>

=== Avionics ===
{{Main|Avionics}}
The avionics comprise any ''electronic'' [[aircraft flight control system]]s and related equipment, including electronic [[cockpit]] instrumentation, navigation, [[radar]], monitoring, and [[communications system]]s.<ref name="websters_3rd_new_intl_dictionary" /><ref name="asa_dictionary_3rd_ed" /><ref name="janes_dictionary_1980" /><ref name="dictionary_of_aviation_1974_fell"/>

== Flight characteristics ==
=== Flight envelope ===
{{Main|Flight envelope}}
The flight envelope of an aircraft refers to its approved design capabilities in terms of [[airspeed]], [[Load factor (aeronautics)|load factor]] and altitude.<ref>{{Cite web|url=http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?type=simple;c=ecfr;cc=ecfr;sid=a8f38006e777ba46ba8000f7c2fe6641;region=DIV1;q1=23.335;rgn=div8;view=text;idno=14;node=14%3A1.0.1.3.10.3.70.8|title=eCFR — Code of Federal Regulations|work=gpoaccess.gov|access-date=1 April 2015|url-status=dead|archive-url=https://web.archive.org/web/20120402202400/http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?type=simple%3Bc%3Decfr%3Bcc%3Decfr%3Bsid%3Da8f38006e777ba46ba8000f7c2fe6641%3Bregion%3DDIV1%3Bq1%3D23.335%3Brgn%3Ddiv8%3Bview%3Dtext%3Bidno%3D14%3Bnode%3D14%3A1.0.1.3.10.3.70.8|archive-date=2 April 2012}}</ref><ref>{{Cite news |title=LOAD FACTOR |url=http://www.access.gpo.gov/ecfr/graphics/pdfs/ec28se91.001.pdf |archive-url=https://web.archive.org/web/20100601204507/http://www.access.gpo.gov/ecfr/graphics/pdfs/ec28se91.001.pdf |archive-date=2010-06-01}}</ref>

=== Range ===
{{Main|Range (aeronautics)}}
[[File:Boeing 777-200LR banking over mountain.jpg|thumb|The [[Boeing 777#777-200LR|Boeing 777-200LR]] is one of the longest-range airliners, capable of flights of more than halfway around the world.]]
The maximal total ''range'' is the maximum distance an aircraft can fly between [[takeoff]] and [[landing]]. [[Powered aircraft]] range is limited by the [[aviation fuel]] energy storage capacity (chemical or electrical) considering both weight and volume limits.<ref>{{cite book |title=A Dictionary of Aviation |first=David W. |last=Wragg |isbn=9780850451634 |edition=first |publisher=Osprey |date=1973 |page=221 }}</ref> [[Unpowered aircraft]] range depends on factors such as cross-country speed and environmental conditions. The range can be seen as the cross-country [[ground speed]] multiplied by the maximum time in the air. The fuel time limit for powered aircraft is fixed by the available fuel (considering reserve fuel requirements) and rate of consumption. The [[Airbus A350#A350-900ULR|Airbus A350-900ULR]] is among the longest range airliners.<ref name=ArBsigger-A000>{{cite web |url=https://www.airbus.com/sites/g/files/jlcbta136/files/2024-04/Airbus-A350-Family-Facts-and-Figures%20April-2024.pdf#page=3 |title=Airbus-A350-Family-Facts-and-Figures April-2024.pdf |year=2024 |website=airbus.com |publisher=Airbus |access-date=18 June 2024 |quote="… Operational flexibility: … The A350-900 Ultra Long Range (ULR) is the latest variant of the A350 Family. Capable of flying 9,700 nautical miles (18,000 kilometres) non-stop, the A350-900ULR offers the longest range of any commercial airliner in service today. …"}}</ref>

Some aircraft can gain energy while airborne through the environment (e.g. collecting solar energy or through rising air currents from mechanical or thermal lifting) or from in-flight refueling. These aircraft could theoretically have an infinite range.

''Ferry range'' means the maximum range that an aircraft engaged in [[ferry flying]] can achieve. This usually means maximum [[fuel]] load, optionally with extra fuel tanks and minimum equipment. It refers to the transport of aircraft without any passengers or cargo. ''[[Combat radius]]'' is a related measure based on the maximum distance a warplane can travel from its base of operations, accomplish some objective, and return to its original airfield with minimal reserves.

=== Flight dynamics ===
{{Main|Aircraft flight dynamics}}
[[File:Flight dynamics with text.svg|thumb|Flight dynamics]]
''Flight dynamics'' is the science of air vehicle orientation and control in three dimensions. The three critical flight dynamics parameters are the [[angles of rotation]] in three [[dimensions]] about the vehicle's [[center of gravity]] (cg), known as ''pitch'', ''roll'' and ''yaw''. These are collectively known as ''aircraft attitude'', often principally relative to the atmospheric frame in normal flight, but also relative to terrain during takeoff or landing, or when operating at low elevation. The concept of attitude is not specific to fixed-wing aircraft, but also extends to [[rotary aircraft]] such as helicopters, and [[dirigibles]], where the flight dynamics involved in establishing and controlling attitude are entirely different.

[[Control system]]s adjust the orientation of a vehicle about its cg. A control system includes control surfaces which, when deflected, generate a moment (or couple from ailerons) about the cg which rotates the aircraft in pitch, roll, and yaw. For example, a [[pitching moment]] comes from a force applied at a distance forward or aft of the cg, causing the aircraft to pitch up or down.

A [[fixed-wing aircraft]] increases or decreases the lift generated by the wings when it pitches nose up or down by increasing or decreasing the [[angle of attack]] (AOA). The roll angle is also known as bank angle on a fixed-wing aircraft, which usually "banks" to change the horizontal direction of flight. An aircraft is streamlined from nose to tail to reduce [[Drag (physics)|drag]] making it advantageous to keep the [[Slip (aerodynamics)|sideslip angle]] near zero, though an aircraft may be deliberately "sideslipped" to increase drag and descent rate during landing, to keep aircraft heading same as runway heading during cross-wind landings and during flight with asymmetric power.<ref>{{Cite book |last=Defense Technical Information Center |url=https://archive.org/details/DTIC_ADA124610 |title=DTIC ADA124610: Fixed Wing Stability and Control Theory and Flight Test Techniques. Revision |date=1981-11-01 |language=english |pages=V-5}}</ref>

==== Stability ====
[[File:Aircraft tail.JPG|thumb|The [[empennage]] of a [[Boeing 747|Boeing 747-200]]]]A fixed wing is typically unstable in pitch, roll, and yaw. Pitch and yaw stabilities of conventional fixed wing designs require [[Stabilizer (aeronautics)|horizontal and vertical stabilisers]],<ref name="Crane">Crane, Dale: ''Dictionary of Aeronautical Terms, third edition'', p. 194. Aviation Supplies & Academics, 1997. {{ISBN|1-56027-287-2}}</ref><ref name="GroundUp">Aviation Publishers Co. Limited, ''From the Ground Up'', p. 10 (27th revised edition) {{ISBN|0-9690054-9-0}}</ref> which act similarly to the feathers on an arrow.<ref>{{Cite web|url=http://www.airlines.org/ATAResources/Handbook/Pages/AirlineHandbookChapter5HowAircraftFly.aspx|title=Airline Handbook Chapter 5: How Aircraft Fly|work=Airline Handbook|url-status=dead|archive-url=https://web.archive.org/web/20100620150339/http://airlines.org/ATAResources/Handbook/Pages/AirlineHandbookChapter5HowAircraftFly.aspx|archive-date=20 June 2010|publisher=[[Airlines for America|Air Transport Association]]}}</ref> These stabilizing surfaces allow equilibrium of aerodynamic forces and to stabilise the [[flight dynamics]] of pitch and yaw.<ref name="Crane" /><ref name="GroundUp" />

==== Control ====
{{Empty section|date=March 2025}}

== Environmental impact ==
{{Main|Environmental impact of aviation}}

Aircraft engines produce gases, [[aircraft noise|noise]], and [[particulates]] from [[fossil fuel]] combustion, raising [[environment (biophysical)|environmental]] concerns over their global effects and on local air quality.<ref>{{cite web | url=https://www.icao.int/environmental-protection/pages/aircraft-engine-emissions.aspx | title=Aircraft Engine Emissions | publisher=[[International Civil Aviation Organization]] | access-date=23 October 2020 | archive-date=27 July 2019 | archive-url=https://web.archive.org/web/20190727040541/https://www.icao.int/environmental-protection/Pages/aircraft-engine-emissions.aspx | url-status=live}}</ref>

[[Jet airliners]] contribute to [[climate change]] by emitting [[carbon dioxide]] ({{CO2}}), the best understood [[greenhouse gas]], and, with less [[Scientific method|scientific understanding]], [[nitrogen oxides]], [[condensation trails|contrails]] and particulates. Their [[radiative forcing]] is estimated at 1.4 that of {{CO2}} alone, excluding induced [[cirrus cloud]] with a very low level of scientific understanding.
In 2018, global commercial operations generated 2.4% of {{CO2}} emissions.<ref name=ICCTsep2019>{{cite web | url=https://theicct.org/sites/default/files/publications/ICCT_CO2-commercl-aviation-2018_20190918.pdf | title=CO2 emissions from commercial aviation, 2018 | author=Brandon Graver | author2=Kevin Zhang | author3=Dan Rutherford | date=September 2019 | publisher=[[International Council on Clean Transportation]] | access-date=10 January 2020 | archive-date=20 November 2019 | archive-url=https://web.archive.org/web/20191120065456/https://theicct.org/sites/default/files/publications/ICCT_CO2-commercl-aviation-2018_20190918.pdf | url-status=live}}</ref> Jet airliners have become more fuel efficient and {{CO2}} emissions per revenue [[ton-kilometer]] (RTK) in 2018 were 47% of those in 1990. In 2018, {{CO2}} emissions averaged 88 grams of {{CO2}} per revenue passenger per km. While the [[aviation]] industry is more [[fuel efficient]], overall emissions have risen as the volume of [[air travel]] has increased. By 2020, aviation emissions were 70% higher than in 2005 and they could grow by 300% by 2050.<ref name=EC-aviation>{{Cite web | url=https://ec.europa.eu/clima/policies/transport/aviation_en | title=Reducing emissions from aviation | website=Climate Action | date=23 November 2016 | publisher=European Commission | access-date=1 June 2019 | archive-date=22 June 2018 | archive-url=https://web.archive.org/web/20180622053225/https://ec.europa.eu/clima/policies/transport/aviation_en | url-status=live}}</ref>

[[Aircraft noise pollution]] disrupts [[sleep]], children's education and could increase [[cardiovascular risk]]. [[Airports]] can generate [[water pollution]] due to their extensive handling of [[jet fuel]] and [[deicing]] chemicals if not [[spill containment|contained]], contaminating nearby water bodies. Aviation activities emit [[ozone]] and [[ultrafine particles]], both of which are [[health hazard]]s. Piston engines used in [[general aviation]] burn [[Avgas]], releasing [[Lead poisoning|toxic lead]].

Aviation's environmental footprint can be reduced by better [[fuel economy in aircraft]], or [[air traffic control]] and [[Airway (aviation)|flight routes]] can be optimized to lower non-{{CO2}} effects on climate from {{chem2|NOx}}, particulates or contrails.
[[Aviation biofuel]], [[emissions trading]] and [[carbon offsetting]], part of the [[ICAO]]'s [[Carbon Offsetting and Reduction Scheme for International Aviation|CORSIA]], can lower {{CO2}} emissions. Aviation usage can be lowered by [[short-haul flight ban]]s, [[Airport rail link#Mainline rail|train connections]], [[Flight shame|personal choices]] and [[aviation taxation and subsidies]]. Fuel-powered aircraft may be replaced by [[hybrid electric aircraft]] and [[electric aircraft]] or by [[hydrogen-powered aircraft]].
Since 2021, the [[International Air Transport Association|IATA]] members plan net-zero carbon emissions by 2050, followed by the [[International Civil Aviation Organization|ICAO]] in 2022.

== Uses for aircraft ==
=== Military ===
[[File:Color Photographed B-17E in Flight.jpg|thumb|[[Boeing B-17 Flying Fortress|Boeing B-17E]] in flight]]
{{Main|Military aircraft}}
A military aircraft is any aircraft that is operated by a legal or insurrectionary armed service of any type.<ref name="gunston" /> Military aircraft can be either combat or non-combat:

* Combat aircraft are aircraft designed to destroy enemy equipment using its own armament.<ref name="gunston" /> Combat aircraft are typically developed and procured only by military forces.
* Non-combat aircraft, such as [[military transport aircraft|transports]] and [[Tanker (aircraft)|tankers]], are not designed for combat as their primary function but may carry weapons for self-defense. These mainly operate in support roles, and may be developed by either military forces or civilian organizations.

=== Civil ===
[[File:Pilatus Agusta A109 Flug.jpg|thumb|[[AgustaWestland AW109|Agusta A109]] helicopter of the [[Rega (air rescue)|Swiss air rescue service]]]]
{{Main|Civil aviation}}
''Civil aviation'' is one of two major categories of flying, representing all non-military and non-state [[aviation]], which can be both private and commercial. Most countries in the world are members of the [[International Civil Aviation Organization]] and work together to establish common [[Standards and Recommended Practices]] for civil aviation through that agency.

Civil aviation includes three major categories:

* [[Airline|Commercial air transport]], including scheduled and non-scheduled passenger and cargo flights
* Aerial work, in which an aircraft is used for specialized services such as agriculture, photography, surveying, search and rescue, etc.
* [[General aviation]] (GA), including all other civil flights, private or commercial<ref name="ICAO">{{cite book |chapter-url=https://www.verifavia.com/bases/ressource_pdf/299/icao-annex-6-part-i.pdf |archive-url=https://web.archive.org/web/20230318231957/https://www.verifavia.com/bases/ressource_pdf/299/icao-annex-6-part-i.pdf |archive-date=18 March 2023 |title=Annex 6, Operation of Aircraft Part I, International Commercial Air Transport – Aeroplanes |edition=9 |date=July 2010 |publisher=International Civil Aviation Organization (ICAO) |chapter=1. Definitions |pages=1, 3 and 5 |isbn=9789292315368 |access-date=17 March 2019}}
</ref>

Although scheduled air transport is the larger operation in terms of passenger numbers, GA is larger in the number of flights (and flight hours, in the U.S.<ref>{{cite web |url=https://www.ntsb.gov/aviation/Table1.htm |title=NTSB - Aviation Accident Statistics |access-date=2009-08-16 |url-status=live |archive-url=https://web.archive.org/web/20090901224856/https://www.ntsb.gov/aviation/Table1.htm |archive-date=2009-09-01 }}</ref>) In the U.S., GA carries 166 million passengers each year,<ref>{{cite web |url=http://www.gaservingamerica.com/Advantages_of_GA.htm |title=Advantages of General Aviation vs. Airline, Faster, Better, Cheaper, More Secure |access-date=2008-09-03 |url-status=live |archive-url=https://web.archive.org/web/20080913211501/http://www.gaservingamerica.com/Advantages_of_GA.htm |archive-date=2008-09-13 }}</ref> more than any individual airline, though less than all the airlines combined. Since 2004, the U.S. airlines combined have carried over 600 million passengers each year, and in 2014, they carried a combined 662,819,232 passengers.<ref>United States Department of Transportation. "[http://www.rita.dot.gov/bts/data_and_statistics/by_mode/airline_and_airports/airline_passengers.html Bureau of Transportation Statistics] {{webarchive|url=https://web.archive.org/web/20150725013700/http://www.rita.dot.gov/bts/data_and_statistics/by_mode/airline_and_airports/airline_passengers.html |date=2015-07-25 }}". Retrieved 24 July 2015</ref>

Some countries also make a regulatory distinction based on whether aircraft are flown for hire, like:

* [[Commercial aviation]] includes most or all flying done for hire, particularly scheduled service on [[airline]]s; and
* [[Private aviation]] includes pilots flying for their own purposes (recreation, business meetings, etc.) without receiving any kind of remuneration.
[[File:British Airways Boeing 747-400 (G-CIVH) departs London Heathrow 11Apr2015 arp.jpg|thumb|A [[British Airways]] [[Boeing 747-400]] departs [[Heathrow Airport|London Heathrow International Airport]]. This is an example of a [[commercial aviation]] service.]]
All scheduled air transport is commercial, but general aviation can be either commercial or private. Normally, the pilot, aircraft, and operator must all be authorized to perform commercial operations through separate commercial licensing, registration, and operation certificates.

=== Experimental ===
{{Main|Experimental aircraft}}
[[File:MiniCeline ultralight aircraft.jpeg|thumb|A model aircraft, weighing six grams]]
An ''experimental aircraft'' is an aircraft intended for testing new [[aerospace]] technologies and design concepts.

The term ''research aircraft'' or ''[[testbed aircraft]]'', by contrast, generally denotes aircraft modified to perform scientific studies, such as weather research or geophysical surveying, similar to a [[research vessel]].<ref>{{Cite web |title=NOAA research aircraft |url=https://www.aoml.noaa.gov/hrd/about_hrd/aircraft.html |access-date=2024-09-29 |website=US NOAA}}</ref>

The term "experimental aircraft" also has specific legal meaning in Australia, the United States and some other countries; usually used to refer to aircraft flown with an [[Airworthiness certificate#Special airworthiness certificate|experimental certificate]].<ref>[http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgFAR.nsf/0/71F1608EE6AAF580862576E4005B24C6?OpenDocument 14CFR 21.175] {{Webarchive|url=https://web.archive.org/web/20180912092021/http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgFAR.nsf/0/71F1608EE6AAF580862576E4005B24C6?OpenDocument |date=2018-09-12 }}, US Federal Aviation Administration. Retrieved 2018-01-12</ref> In the [[United States]], this also includes most [[homebuilt aircraft]], many of which are based on conventional designs and hence are experimental only in name because of certain restrictions in operation.<ref>[http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgFAR.nsf/0/A9986A485C9E636386256EDF00510840?OpenDocument 14CFR 21.191] {{Webarchive|url=https://web.archive.org/web/20210610094213/http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgFAR.nsf/0/A9986A485C9E636386256EDF00510840?OpenDocument |date=2021-06-10 }}, US Federal Aviation Administration. Retrieved 2018-01-12</ref>

=== Model ===
{{Main|Model aircraft}}{{Empty section|date=March 2025}}

== See also ==

=== Lists ===
* [[Early flying machines]]
* [[Flight altitude record]]
* [[List of aircraft]]
* [[List of civil aircraft]]
* [[List of fighter aircraft]]
* [[List of individual aircraft]]
* [[List of large aircraft]]
* [[wikt:Appendix:Glossary of aviation, aerospace, and aeronautics|List of aviation, aerospace and aeronautical terms]]

=== Topics ===
* [[Aircraft hijacking]]
* [[Aircraft spotting]]
* [[Air traffic control]]
* [[Airport]]
* [[Flying car]]
* [[Personal air vehicle]]
* [[Powered parachute]]
* [[Spacecraft]]
* [[Spaceplane]]

== References ==
{{Reflist|refs=
<ref name="gunston">Gunston 1986, p. 274</ref>
}}
* {{Cite book|last=Gunston|first=Bill|title=Jane's Aerospace Dictionary 1987|year=1987|publisher=Jane's Publishing Company Limited|location=London, England|isbn=978-0-7106-0365-4}}

== External links ==
{{Wiktionary|aircraft}}
{{Commons category}}

===History===
* [http://www.hq.nasa.gov/office/pao/History/SP-468/contents.htm The Evolution of Modern Aircraft (NASA)] {{Webarchive|url=https://web.archive.org/web/20071227182437/http://www.hq.nasa.gov/office/pao/History/SP-468/contents.htm |date=27 December 2007 }}
* [https://invention.psychology.msstate.edu/Tale_of_Airplane/taleplane.html Virtual Museum]
* [http://www.nasm.si.edu/ Smithsonian Air and Space Museum] – online collection with a particular focus on history of aircraft and spacecraft
* [http://www.life.com/image/first/in-gallery/36582/amazing-early-flying-machines Amazing Early Flying Machines] {{Webarchive|url=https://web.archive.org/web/20091213011847/http://www.life.com/image/first/in-gallery/36582/amazing-early-flying-machines |date=13 December 2009 }} slideshow by ''[[Life (magazine)|Life]]'' magazine

===Information===
* [http://www.airliners.net/ Airliners.net]
* [https://web.archive.org/web/20080624032037/http://www.aviationdictionary.org/ Aviation Dictionary] – free aviation terms, phrases and jargons
* [https://www.newscientist.com/topic/aviation ''New Scientist''{{'}}s aviation page]

{{Aircraft types (by method of thrust and lift)}}
{{Lists of aircraft}}
{{Aircraft components}}

{{Authority control}}

[[Category:Aircraft| ]]

International Labour Organization

2025-07-11T16:41:22Z

45.232.105.68:

{{Short description|Specialized agency of the United Nations}}
{{redirect|ILO||Ilo (disambiguation)}}
{{Use dmy dates|date=May 2020}}

{{Infobox organization
| name = International Labour Organization<ref name="UIA" />
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|staff= 3,651
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| logo_caption =
| type = [[List of specialized agencies of the United Nations|United Nations specialized agency]]
| abbreviation = ILO
| languages = {{hlist|[[English language|English]]|[[Spanish language|Spanish]]|[[French language|French]]}}
| leader_title = Director-general
| leader_name = [[Gilbert Houngbo]]
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| headquarters = [[Geneva]], Switzerland
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| website = {{official URL}}
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| subsidiaries =
}}
The '''International Labour Organization''' ('''ILO''') is a [[United Nations]] agency whose mandate is to advance social and economic justice by setting [[international labour standards]].<ref name="UIA">{{Cite web |url=https://uia.org/s/or/en/1100025992 |url-access= |title=International Labour Organization (ILO) |author1=Staff writer |year=2024 |department=UIA Global Civil Society Database |website=uia.org |publisher=[[Union of International Associations]] |agency=Yearbook of International Organizations Online |location=Brussels, Belgium |format= |arxiv= |asin= |bibcode= |doi= |isbn= |issn= |jfm= |jstor= |lccn= |mr= |oclc= |ol= |osti= |pmc= |pmid= |rfc= |ssrn= |zbl= |id= |access-date=24 December 2024 |url-status= |archive-url= |archive-date= |via= |quote= |trans-quote= }}</ref><ref name=":1">{{cite web|url=http://www.ilo.org/global/about-the-ilo/mission-and-objectives/lang--en/index.htm|title=Mission and impact of the ILO|work=International Labour Organization |date=28 January 2024 |url-status=live |archive-url= https://web.archive.org/web/20240301081628/http://www.ilo.org/global/about-the-ilo/mission-and-objectives/lang--en/index.htm |archive-date= Mar 1, 2024 }}</ref> Founded in October 1919 under the [[League of Nations]], it is one of the first and oldest [[List of specialized agencies of the United Nations|specialized agencies of the UN]]. The ILO has [[Member states of the International Labour Organization|187 member states]]: 186 out of 193 [[Member states of the United Nations|UN member states]] plus the [[Cook Islands]]. It is headquartered in [[Geneva]], Switzerland, with around 40 field offices around the world, and employs some 3,381 staff across 107 nations, of whom 1,698 work in technical cooperation programmes and projects.<ref>{{cite web|title=Departments and offices|url=https://www.ilo.org/global/about-the-ilo/how-the-ilo-works/departments-and-offices/lang--en/index.htm|access-date=2021-07-15|website=International Labour Organization|language=en |url-status=dead |archive-url= https://web.archive.org/web/20210812101027/https://www.ilo.org/global/about-the-ilo/how-the-ilo-works/departments-and-offices/lang--en/index.htm |archive-date= Aug 12, 2021 }}</ref>

The ILO's standards are aimed at ensuring accessible, productive, and sustainable [[Work (human activity)|work]] worldwide in conditions of freedom, equity, security and dignity.<ref>{{cite web|url=https://www.ilo.org/global/standards/lang--en/index.htm|title=Labour standards |website=International Labour Organization|language=en|access-date=2020-04-27 |url-status=live |archive-url=https://web.archive.org/web/20200501235733/https://www.ilo.org/global/standards/lang--en/index.htm |archive-date= May 1, 2020 }}</ref><ref name="international labour standards2">{{cite web|url=https://www.ilo.org/global/standards/introduction-to-international-labour-standards/lang--en/index.htm|title=Introduction to International Labour Standards|work=International Labour Organization |url-status=dead |archive-url=https://web.archive.org/web/20231231132132/https://www.ilo.org/global/standards/introduction-to-international-labour-standards/lang--en/index.htm |archive-date= Dec 31, 2023 }}</ref> They are set forth in [[List of International Labour Organization Conventions|189 conventions and treaties]], of which eight are classified as fundamental according to the 1998 [[Declaration on Fundamental Principles and Rights at Work]]; together they protect freedom of association and the effective recognition of the right to [[collective bargaining]], the elimination of forced or compulsory labour, the abolition of [[child labour]], and the elimination of [[employment discrimination|discrimination]] in respect of [[employment]] and occupation. The ILO is a major contributor to [[international labour law]].

Within the UN system the organization has a unique tripartite structure: all standards, policies, and programmes require discussion and approval from the representatives of governments, employers, and workers. This framework is maintained in the ILO's three main bodies: The International Labour Conference, which meets annually to formulate international labour standards; the Governing Body, which serves as the executive council and decides the agency's policy and budget; and the International Labour Office, the permanent secretariat that administers the organization and implements activities. The secretariat is led by the Director-General, [[Gilbert Houngbo]] of Togo, who was elected by the Governing Body in 2022.

In 2019, the organization convened the Global Commission on the Future of Work, whose report made ten recommendations for governments to meet the challenges of the 21st century labour environment; these include a universal labour guarantee, social protection from birth to old age and an entitlement to lifelong learning.<ref>{{cite web|url=http://www.ilo.org/global/topics/future-of-work/WCMS_569528/lang--en/index.htm|title=Global Commission on the Future of Work |website=International Labour Organization|date=14 August 2017 |language=en|access-date=2019-03-21 |url-status=live |archive-url= https://web.archive.org/web/20190321141919/http://www.ilo.org/global/topics/future-of-work/WCMS_569528/lang--en/index.htm|archive-date=2019-03-21 }}</ref><ref>{{cite web|url=http://www.ilo.org/global/about-the-ilo/newsroom/news/WCMS_663006/lang--en/index.htm|title=A human-centred agenda needed for a decent future of work|date=2019-01-22|website=International Labour Organization|language=en|access-date=2019-03-21}}</ref> With its focus on international development, it is a member of the United Nations Development Group, a coalition of UN organizations aimed at helping meet the [[Sustainable Development Goals]].

Two milestones in the history of the ILO were the [[Versailles Treaty|Treaty of Versailles]] in 1919, establishing the International Labour Organization, Article 427. And secondly, the [[Declaration of Philadelphia]] in 1944, reestablishing the ILO under the [[United Nations]] and reaffirming the first principle that "labour is not a [[commodity]]".

{{TOC limit|3}}

==Structure==
[[File:OIT, Genève.jpg|thumb|ILO headquarters in [[Geneva]], Switzerland]]
The ILO is a specialized agency of the United Nations (UN).<ref>{{cite web |title=International Labour Organization |url=https://www.britannica.com/EBchecked/topic/290987/International-Labour-Organization-ILO |access-date=24 May 2012 |publisher=britannica.com}}</ref> As with other UN specialized agencies (or programmes) working on [[international development]], the ILO is also a member of the [[United Nations Development Group]].<ref>{{cite web |title=Home |url=http://www.undg.org/index.cfm?P=13p |url-status=dead |archive-url=https://web.archive.org/web/20131013125243/http://www.undg.org/index.cfm?P=13p |archive-date=13 October 2013 |access-date=2011-05-22}}</ref>

Unlike other United Nations specialized agencies, the International Labour Organization (ILO) has a [[Tripartism|tripartite]] governing structure that brings together governments, employers, and workers of 187 member States, to set labour standards, develop policies and devise programmes promoting decent work for all women and men. The structure is intended to ensure the views of all three groups are reflected in ILO labour standards, policies, and programmes, though governments have twice as many representatives as the other two groups.

=== Governing body ===
The Governing Body is the [[Executive (government)|executive body]] of the International Labour Organization. It meets three times a year, in March, June and November. It takes decisions on ILO policy, decides the agenda of the International Labour Conference, adopts the draft Programme and Budget of the Organization for submission to the Conference, elects the Director-General, requests information from the member states concerning labour matters, appoints commissions of inquiry and supervises the work of the International Labour Office.

The Governing Body is composed of 56 titular members (28 governments, 14 employers and 14 workers) and 66 deputy members (28 governments, 19 employers and 19 workers).

Ten of the titular government seats are permanently held by States of chief industrial importance: [[Brazil]], [[China]], [[France]], [[Germany]], [[India]], [[Italy]], [[Japan]], the [[Russian Federation]], the [[United Kingdom]] and the [[United States]].<ref>{{cite web|title=Governing Body|url=http://www.ilo.org/global/about-the-ilo/how-the-ilo-works/governing-body/lang--en/index.htm|publisher=International Labour Organization|access-date=24 May 2012}}</ref> The other Government members are elected by the Conference every three years (the last elections were held in June 2021).<ref>{{Cite web |title=Governing Body elections (International Labour Conference (ILC)) |url=https://www.ilo.org/ilc/Governingbodyelections/lang--en/index.htm |access-date=2023-12-11 |website=www.ilo.org |language=en}}</ref> The Employer and Worker members are elected in their individual capacity.<ref>[[s:Constitution of the International Labour Organization|Article 7, ILO Constitution]]</ref><ref>{{cite web|title=ILO Constitution|url=http://www.ilo.org/public/english/bureau/leg/amend/index.htm|publisher=International Labour Organization}}</ref>

=== Director-General ===
On 25 March 2022 [[Gilbert Fossoun Houngbo]] was elected Director-General of ILO.<ref>{{cite web
| title=Gilbert Houngbo will be the first African to lead the ILO
| work=republicoftogo.com
| date=25 March 2022
| url=https://www.republicoftogo.com/toutes-les-rubriques/in-english/gilbert-houngbo-will-be-the-first-african-to-lead-the-ilo
}}</ref> On 1 October 2022 he succeeded [[Guy Ryder]], who was elected by the ILO Governing Body in October 2012, and re-elected for a second five-year-term in November 2016.<ref>{{cite web
| title=Guy Ryder re-elected as ILO Director-General for a second term
| work=International Labour Organization
| date=7 November 2016
| url=https://www.ilo.org/global/about-the-ilo/newsroom/news/WCMS_534283/lang--en/index.htm
}}</ref> He is the organization's first African Director-General. In 2024, a group of African countries that play a crucial role visited the International Labour Office, such as Morocco, where they held talks with the Minister of Economic Integration, Small Business, Employment, and Skills Development, Younes Sekouri.<ref name="f990">{{cite web |last1=Taibi |first1=FADLI |last2=Technology |first2=Archos |date=2024-01-17 |title=ILO DG Lauds Morocco's Experience in Implementing Social State Policy |url=https://www.mapnews.ma/en/actualites/economy/ilo-dg-lauds-moroccos-experience-implementing-social-state-policy |access-date=2024-05-08 |website=MapNews |language=fr}}</ref>
The list of the Directors-General of ILO since its establishment in 1919 is as follows:<ref>ILO official site: [https://www.ilo.org/global/about-the-ilo/how-the-ilo-works/ilo-director-general/former-directors-general/lang--en/index.htm Former Directors-General]</ref>

{| class="wikitable"
|-
!Name
!Country
!Term
|-
| [[Albert Thomas (minister)|Albert Thomas]] || {{flagcountry|FRA}} || 1919–1932
|-
| [[Harold Butler (civil servant)|Harold Butler]] || {{flagcountry|UK}} || 1932–1938
|-
| [[John G. Winant]] || {{flagcountry|USA}} || 1939–1941
|-
| [[Edward J. Phelan]] || {{flagcountry|IRL}} || 1941–1948
|-
| [[David A. Morse]] || {{flagcountry|USA}} || 1948–1970
|-
| [[Clarence Wilfred Jenks]] || {{flagcountry|UK}} || 1970–1973
|-
| [[Francis Blanchard]] || {{flagcountry|FRA}} || 1974–1989
|-
| [[Michel Hansenne]] || {{flagcountry|BEL}} || 1989–1999
|-
| [[Juan Somavía]] || {{flagcountry|CHL}} || 1999–2012
|-
| [[Guy Ryder]] || {{flagcountry|UK}} || 2012–2022
|-
| [[Gilbert Houngbo]] || {{flagcountry|TOG}} || 2022–present
|}

=== Membership ===
{{further|Member states of the International Labour Organization}}
[[File:International Labour Organization flag.jpg|thumb|International Labour Organization flag]]
The ILO has 187 state members. 186 of the 193 [[member states of the United Nations]] plus the [[Cook Islands]] are members of the ILO.<ref>{{cite web|title=ILO Constitution Article 3|url=http://www.ilo.org/ilolex/english/constq.htm|archive-url=http://arquivo.pt/wayback/20091225111436/http://www.ilo.org/ilolex/english/constq.htm|url-status=dead|archive-date=25 December 2009|publisher=Ilo.org|access-date=2 June 2012}}</ref> The UN member states which are not members of the ILO are [[Andorra]], [[Bhutan]], [[Liechtenstein]], [[Federated States of Micronesia|Micronesia]], [[Monaco]], [[Nauru]], and [[North Korea]].<ref>{{cite web |title=ILO Declaration on Fundamental Prinicples & Rights at Work |url=https://sthelenaehrc.org/ilo-declaration-on-fundamental-prinicples-rights-at-work/ |website=Equality & Human Rights Commission |date=10 November 2020 |access-date=21 August 2023}}</ref>

The ILO constitution permits any member of the UN to become a member of the ILO. To gain membership, a nation must inform the director-general that it accepts all the obligations of the ILO constitution.<ref name=EotN-Membership>{{cite encyclopedia|title=The International Labour Organization (ILO) – Membership|url=http://www.nationsencyclopedia.com/United-Nations-Related-Agencies/The-International-Labour-Organization-ILO-MEMBERSHIP.html|encyclopedia=Encyclopedia of the Nations|publisher=Advameg, Inc.|access-date=16 August 2012|year=2012}}</ref> Other, non-UN states can be admitted by a two-thirds vote of all delegates, including a two-thirds vote of government delegates, at any ILO General Conference. The Cook Islands, a non-UN state, joined in June 2015.<ref>International Labour Organization. (n.d.). ''About the ILO in the Cook Islands.'' Retrieved June 26, 2021, from https://www.ilo.org/suva/countries-covered/cook-islands/WCMS_410209/lang--en/index.htm</ref><ref name=":8">{{Cite web |title=Key document - ILO Constitution |url=https://www.ilo.org/dyn/normlex/en/f?p=1000:62:0::NO:62:P62_LIST_ENTRIE_ID:2453907:NO |access-date=2024-03-23 |website=www.ilo.org}}</ref>

Countries that had been members of the ILO under the League of Nations remained members when the organization's new constitution came into effect in 1946.<ref name=":8" />

== Objectives ==
The [[Declaration of Philadelphia]] (10 May 1944) restated the traditional objectives of the International Labour Organization and then branched out in two new directions: the centrality of [[Labour rights|human rights]] to [[social policy]], and the need for international economic planning.<ref name="Dufty">Norman F. Dufty, [https://www.jstor.org/stable/2706128 "Organizational Growth and Goal Structure: The Case of the ILO"], (1972) 26 (3) ''International Organization'' 479 accessed 24 August 2011</ref>{{Rp|481–2}} With the end of the world war in sight, it sought to adapt the guiding principles of the ILO "to the new realities and to the new aspirations aroused by the hopes for a better world."<ref name="Sulkowski">Joseph Sulkowski, [https://www.jstor.org/stable/2194455 "The Competence of the International Labor Organization Under the United Nations System"], (1951) 45 (2) ''The American Journal of International Law'' 286 accessed 24 August 2011.</ref>{{Rp|287}} It was adopted at the 26th Conference of the ILO in [[Philadelphia]], United States of America.<ref name="Dufty" />{{Rp|481}}

In 1946, when the ILO's constitution was being revised by the General Conference convened in Montreal, the Declaration of Philadelphia was annexed to the constitution and forms an integral part of it by Article 1.<ref name="Sulkowski" />{{Rp|287}} Most of the demands of the declaration were a result of a partnership of American and Western European labor unions and the ILO secretariat.<ref name="Dufty" />{{Rp|481}}

"Labour is not a commodity" is the principle expressed in the preamble to the International Labour Organization's founding documents. It expresses the view that people should not be treated like inanimate [[commodities]], [[Human capital|capital]], another mere [[factor of production]], or [[Human resources|resources]]. Instead, people who work for a living should be treated as [[Human being|human beings]] and accorded [[dignity]] and respect. [[Paul O'Higgins]] attributes the phrase to [[John Kells Ingram]], who used it in 1880 during a meeting in [[Dublin]] of the British [[Trades Union Congress]].<ref>O'Higgins, P., [https://academic.oup.com/ilj/article-abstract/26/3/225/664238 'Labour is not a Commodity' — an Irish Contribution to International Labour Law'] (1997) 26(3) Industrial Law Journal 225-234</ref>

==History==
===Origins===

It is the first organization for the UN.While the ILO was established as an agency of the [[League of Nations]] following [[World War I]], its founders had made great strides in social thought and action before 1919. The core members all knew one another from earlier private professional and ideological networks, in which they exchanged knowledge, experiences, and ideas on social policy. Pre-war "[[Epistemic community (international relations)|epistemic communities]]", such as the [[International Association for Labour Legislation]] (IALL), founded in 1900, and political networks, such as the [[socialism|socialist]] [[Second International]], were a decisive factor in the institutionalization of international labour politics.<ref name="VanDaele">{{cite journal|author=VanDaele, Jasmien|title=Engineering Social Peace: Networks, Ideas, And the Founding of the International Labour Organization|journal=International Review of Social History|year= 2005 |volume=50|issue=3|pages= 435–466|doi=10.1017/S0020859005002178|doi-access=free}}</ref>

In the post-World War I euphoria, the idea of a "makeable society" was an important catalyst behind the social engineering of the ILO architects. As a new discipline, international labour law became a useful instrument for putting social reforms into practice. The utopian ideals of the founding members—social justice and the right to decent work—were changed by diplomatic and political compromises made at the [[Paris Peace Conference, 1919|Paris Peace Conference]] of 1919, showing the ILO's balance between idealism and pragmatism.<ref name="VanDaele" />

Over the course of the First World War, the international [[labour movement]] proposed a comprehensive programme of protection for the working classes, conceived as compensation for labour's support during the war.{{clarify|date=August 2012}} Post-war reconstruction and the protection of labour unions occupied the attention of many nations during and immediately after World War I. In Great Britain, the [[National Whitley Council|Whitley Commission]], a subcommittee of the Reconstruction Commission, recommended in its July 1918 Final Report that "industrial councils" be established throughout the world.<ref>Haimson, Leopold H. and Sapelli, Giulio. ''Strikes, Social Conflict, and the First World War: An International Perspective.'' Milan: Fondazione Giangiacomo Feltrinelli, 1992. {{ISBN|88-07-99047-4}}</ref> The [[Labour Party (UK)|British Labour Party]] had issued its own reconstruction programme in the document titled ''Labour and the New Social Order''.<ref>{{cite journal|author=Shapiro, Stanley|title=The Passage of Power: Labor and the New Social Order|journal=Proceedings of the American Philosophical Society|volume=120|year=1976|jstor=986599|issue=6|pages=464–474}}</ref> In February 1918, the third [[Inter-Allied Socialist Conferences of World War I|Inter-Allied Labour and Socialist Conference]] (representing delegates from Great Britain, France, Belgium and Italy) issued its report, advocating an international labour rights body, an end to secret diplomacy, and other goals.<ref>[[Iwao Ayusawa|Ayusawa, Iwao Frederick]]. ''International Labour Legislation''. Clark, N.J.: Lawbook Exchange, 2005. {{ISBN|1-58477-461-4}}</ref> And in December 1918, the [[American Federation of Labor]] (AFL) issued its own distinctively apolitical report, which called for the achievement of numerous incremental improvements via the [[collective bargaining]] process.<ref name="Foner">Foner, Philip S. ''History of the Labor Movement in the United States. Vol. 7: Labor and World War I, 1914–1918.'' New York: International Publishers, 1987. {{ISBN|0-7178-0638-3}}</ref>

====IFTU Bern Conference====
As the war drew to a close, two competing visions for the post-war world emerged. The first was offered by the [[International Federation of Trade Unions]] (IFTU), which called for a meeting in [[Bern]], Switzerland, in July 1919. The Bern meeting would consider both the future of the IFTU and the various proposals which had been made in the previous few years. The IFTU also proposed including delegates from the [[Central Powers]] as equals. [[Samuel Gompers]], president of the AFL, boycotted the meeting, wanting the Central Powers delegates in a subservient role as an admission of guilt for their countries' role in bringing about war. Instead, Gompers favoured a meeting in Paris which would consider President [[Woodrow Wilson]]'s [[Fourteen Points]] only as a platform. Despite the American boycott, the Bern meeting went ahead as scheduled. In its final report, the Bern Conference demanded an end to wage labour and the establishment of socialism. If these ends could not be immediately achieved, then an international body attached to the League of Nations should enact and enforce legislation to protect workers and trade unions.<ref name="Foner" />

====Commission on International Labour Legislation====
Meanwhile, the [[Paris Peace Conference, 1919|Paris Peace Conference]] sought to dampen public support for communism. Subsequently, the [[Allies of World War I|Allied Powers]] agreed that clauses should be inserted into the emerging peace treaty protecting labour unions and workers' rights, and that an international labour body be established to help guide international labour relations in the future. The advisory Commission on International Labour Legislation was established by the Peace Conference to draft these proposals. The Commission met for the first time on 1 February 1919, and Gompers was elected as the chairman.<ref name="Foner" />

[[File:Picture of Samuel Gompers.jpg|thumb|upright|left|Samuel Gompers (right) with [[Albert Thomas (minister)|Albert Thomas]], 1918]]
Two competing proposals for an international body emerged during the Commission's meetings. The British proposed establishing an international parliament to enact labour laws which each member of the League would be required to implement. Each nation would have two delegates to the parliament, one each from labour and management.<ref name="Foner" /> An international labour office would collect statistics on labour issues and enforce the new international laws. Philosophically opposed to the concept of an international parliament and convinced that international standards would lower the few protections achieved in the United States, Gompers proposed that the international labour body be authorized only to make recommendations and that enforcement be left up to the League of Nations. Despite vigorous opposition from the British, the American proposal was adopted.<ref name="Foner" />

Gompers also set the agenda for the draft charter protecting workers' rights. The Americans made 10 proposals. Three were adopted without change: That labour should not be treated as a [[commodity]]; that all workers had the right to a wage sufficient to live on; and that women should receive equal pay for equal work. A proposal protecting the freedom of speech, press, assembly, and association was amended to include only freedom of association. A proposed ban on the international shipment of goods made by children under the age of 16 was amended to ban goods made by children under the age of 14. A proposal to require an [[eight-hour day|eight-hour work day]] was amended to require the eight-hour work day ''or'' the 40-hour work week (an exception was made for countries where productivity was low). Four other American proposals were rejected. Meanwhile, international delegates proposed three additional clauses, which were adopted: One or more days for weekly rest; equality of laws for foreign workers; and regular and frequent inspection of factory conditions.<ref name="Foner" />

The Commission issued its final report on 4 March 1919, and the Peace Conference adopted it without amendment on 11 April. The report became Part XIII of the [[Treaty of Versailles]].<ref name="Foner" />

===Interwar period===

The first annual International Labour Conference (ILC) began on 29 October 1919 at the [[Pan American Union Building]] in Washington, D.C.<ref>{{cite web|url=http://www.ilo.org/public/libdoc/ilo/P/09616/09616(1919-1).pdf|title=International Labor Conference. October 29, 1919 – November 29, 1919|publisher= Washington Government Printing Office 1920|website= International Labour Organization |archive-url=https://web.archive.org/web/20141012135621/http://www.ilo.org/public/libdoc/ilo/P/09616/09616%281919-1%29.pdf|archive-date=12 October 2014|url-status=live}}</ref> and adopted the first six International Labour Conventions, which dealt with hours of work in industry, unemployment, maternity protection, night work for women, minimum age, and night work for young persons in industry.<ref>{{cite web|url=http://www.ilo.org/public/english/about/history.htm|title=Origins and history|work=International Labour Organization|date=28 January 2024 }}</ref> The prominent French socialist [[Albert Thomas (minister)|Albert Thomas]] became its first director-general.

Despite open disappointment and sharp critique, the revived [[International Federation of Trade Unions]] (IFTU) quickly adapted itself to this mechanism. The IFTU increasingly oriented its international activities around the lobby work of the ILO.<ref>{{cite journal|author=Reiner Tosstorff|title=The International Trade-Union Movement and the Founding of the International Labour Organization|journal=International Review of Social History|year= 2005 |volume=50|issue=3|pages=399–433|doi=10.1017/S0020859005002166|url=http://orca-mwe.cf.ac.uk/3948/1/International_Trade-Union_Movement.pdf|doi-access=free|archive-url=https://web.archive.org/web/20130319131726/http://orca-mwe.cf.ac.uk/3948/1/International_Trade-Union_Movement.pdf|archive-date=19 March 2013|url-status=live}}</ref>

At the time of establishment, the U.S. government was not a member of ILO, as the US Senate rejected the covenant of the League of Nations, and the United States could not join any of its agencies. Following the election of [[Franklin Delano Roosevelt]] to the U.S. presidency, the new administration made renewed efforts to join the ILO without league membership. On 19 June 1934, the U.S. Congress passed a joint resolution authorizing the president to join ILO without joining the League of Nations as a whole. On 22 June 1934, the ILO adopted a resolution inviting the U.S. government to join the organization. On 20 August 1934, the U.S. government responded positively and took its seat at the ILO.
{{Wide image|1919-ILC-secretariatstaff.jpg|950|Greenwood, Ernest H. (of the United States – Deputy secretary general of the conference) / Secretary General: Harold B. Butler (Great Britain) / Deputy Secretaries General: Ernest H. Greenwood (United States) / Guido Pardo (Italy) /Legal Adviser: Manley 0. Hudson (United States) / with staff of the first International Labour Conference, in Washington, D.C., in 1919, in front of the [[Pan American Union Building]]}}

=== Wartime and the United Nations ===
During the [[Second World War]], when Switzerland was surrounded by German troops, ILO director [[John G. Winant]] made the decision to leave Geneva. In August 1940, the [[government of Canada]] officially invited the ILO to be housed at [[McGill University]] in Montreal. Forty staff members were transferred to the temporary offices and continued to work from McGill until 1948.<ref>{{cite web|url=http://www.ilo.org/public/english/support/lib/century/index2.htm|title=ILO|work=International Labour Organization|date=28 January 2024 }}</ref>

The ILO became the first specialized agency of the United Nations system after the demise of the League in 1946.<ref name="e11022">{{cite web|url=https://www.ilo.org/dyn/media/mediasearch.fiche?p_id=16023&p_lang=en|archive-url=https://web.archive.org/web/20170630004817/https://www.ilo.org/dyn/media/mediasearch.fiche?p_id=16023&p_lang=en|url-status=dead|archive-date=30 June 2017|title=Photo Gallery|year=2011|publisher=ILO|access-date=30 May 2011}}</ref> Its constitution, as amended, includes the [[Declaration of Philadelphia]] (1944) on the aims and purposes of the organization.

===Cold War era===

[[File:Minister of Labor Mr. Wilopo is having a conversation with the Deputy Director General of the ILO Dr. R. Rao.jpg|thumb|R. Rao, the Deputy Director General of ILO with [[Wilopo]], the then-Indonesian labor minister, 15 March 1950]]

Beginning in the late 1950s the organization was under pressure to make provisions for the potential membership of ex-colonies which had become independent; in the Director General's report of 1963 the needs of the potential new members were first recognized.<ref>ILO: 'Programme and Structure of the ILO':report of the Director General, 1963.</ref> The tensions produced by these changes in the world environment negatively affected the established politics within the organization<ref>R. W. Cox, "ILO: Limited Monarchy" in R.W. Cox and H. Jacobson ''The Anatomy of Influence: Decision Making in International Organization'' Yale University Press, 1973 pp.102-138</ref> and they were the precursor to the eventual problems of the organization with the USA.

In July 1970, the United States withdrew 50% of its financial support to the ILO following the appointment of an assistant director-general from the Soviet Union. This appointment (by the ILO's British director-general, [[C. Wilfred Jenks]]) drew particular criticism from [[AFL–CIO]] president [[George Meany]] and from New Jersey Assemblyman [[John E. Rooney (politician)|John E. Rooney]]. However, the funds were eventually paid.<ref name="Beigbeder1979">{{cite journal|last=Beigbeder|first=Yves|title=The United States' Withdrawal from the International Labor Organization|journal=Relations Industrielles / Industrial Relations|year=1979|volume=34|issue=2|pages=223–240|url=http://www.erudit.org/revue/ri/1979/v34/n2/028959ar.pdf|doi=10.7202/028959ar|doi-access=free|archive-url=https://web.archive.org/web/20130609070528/http://www.erudit.org/revue/ri/1979/v34/n2/028959ar.pdf|archive-date=9 June 2013|url-status=live}}</ref><ref>{{cite web|title=Communication from the Government of the United States|url=http://www.ilo.org/public/libdoc/ilo/GB/198/GB.198_22_11_engl.pdf |publisher=International Labour Organization|archive-url=https://web.archive.org/web/20150924063409/http://www.ilo.org/public/libdoc/ilo/GB/198/GB.198_22_11_engl.pdf|archive-date=24 September 2015|url-status=live}}. United States letter dated 5 November 1975 containing notice of withdrawal from the International Labour Organization.</ref>

[[File:Tripartite.png|thumb|Ratifications of 1976 [[Tripartite Consultation Convention]]]]

On 12 June 1975, the ILO voted to grant the [[Palestine Liberation Organization]] observer status at its meetings. Representatives of the United States and Israel walked out of the meeting. The [[U.S. House of Representatives]] subsequently decided to withhold funds. The United States gave notice of full withdrawal on 6 November 1975, stating that the organization had become politicized. The United States also suggested that representation from communist countries was not truly "[[Tripartism|tripartite]]"—including government, workers, and employers—because of the structure of these economies. The withdrawal became effective on 1 November 1977.<ref name="Beigbeder1979" />

The United States returned to the organization in 1980 after extracting some concession from the organization. It was partly responsible for the ILO's shift away from a human rights approach and towards support for the [[Washington Consensus]]. Economist [[Guy Standing (Economist)|Guy Standing]] wrote "the ILO quietly ceased to be an international body attempting to redress structural inequality and became one promoting employment equity".<ref name="Standing2008">{{cite journal|last=Standing|first=Guy|title=The ILO: An Agency for Globalization?|journal=Development and Change|year=2008|volume=39|issue=3|pages=355–384|url=http://www.unhistory.org/pdf/StandingILO.pdf|access-date=4 August 2012|doi=10.1111/j.1467-7660.2008.00484.x|citeseerx=10.1.1.593.4931|archive-url=https://web.archive.org/web/20131013085605/http://www.unhistory.org/pdf/StandingILO.pdf|archive-date=13 October 2013|url-status=dead}}</ref>

In 1981, the government of [[Poland]] declared [[martial law]]. It interrupted the activities of [[Solidarność]] detained many of its leaders and members. The ILO Committee on Freedom of Association filed a complaint against Poland at the 1982 International Labour Conference. A Commission of Inquiry established to investigate found Poland had violated ILO Conventions No. 87 on freedom of association<ref>{{cite web|url=https://www.ilo.org/dyn/normlex/en/f?p=NORMLEXPUB:12100:0::NO::P12100_ILO_CODE:C087|title=ILO Conventions No. 98|work=International Labour Organization}}</ref> and No. 98 on trade union rights,<ref>{{cite web|url=https://www.ilo.org/dyn/normlex/en/f?p=NORMLEXPUB:12100:0::NO::P12100_Ilo_Code:C098|title=ILO Conventions No. 98|work=International Labour Organization}}</ref> which the country had ratified in 1957. The ILO and many other countries and organizations put pressure on the Polish government, which finally gave legal status to Solidarność in 1989. During that same year, there was a roundtable discussion between the government and Solidarnoc which agreed on terms of relegalization of the organization under ILO principles. The government also agreed to hold the first free elections in Poland since the Second World War.<ref>{{cite journal|url=https://www.ilo.org/budapest/information-resources/press-releases/WCMS_477275/lang--en/index.htm|title=The ILO and the story of Solidarnoc|website=International Labour Organization|date=3 May 2016}}</ref>

==Offices==
===ILO headquarters===
[[File:Cwr aerial 1937.jpg|thumb|[[Centre William Rappard]], seat of the ILO between 1926 and 1974, now hosting the [[World Trade Organization|WTO]]]]
The ILO is headquartered in Geneva, Switzerland. In its first months of existence in 1919, it offices were located in London, only to move to Geneva in the summer 1920. The first seat in Geneva was on the Pregny hill in the ''Ariana'' estate, in the building that used to host the Thudicum boarding school and currently the headquarters of the [[International Committee of the Red Cross]]. As the office grew, the Office relocated to a purpose-built headquarters by the shores of [[lake Leman]], designed by [[Georges Épitaux]] and inaugurated in 1926 (currently the seat of the [[World Trade Organization]]). During the [[Second World War]] the Office was temporarily relocated to [[McGill University]] in [[Montreal]], Canada.

The current seat of the ILO's headquarters is located on the Pregny hill, not far from its initial seat. The building, a biconcave rectangular block designed by [[Eugène Beaudoin]], [[Pier Luigi Nervi]] and [[Alberto Camenzind]], was purpose-built between 1969–1974 in a severe rationalist style and, at the time of construction, constituted the largest administrative building in Switzerland.<ref>{{cite web|url=https://www.ilo.org/global/about-the-ilo/mission-and-objectives/features/WCMS_649270/lang--en/index.htm|title=A house for social justice - past, present and future|website=International Labour Organization|date=9 November 2018|access-date=8 December 2020}}</ref>

===Regional offices===
* Regional Office for [[Africa]], in [[Abidjan]], Côte d'Ivoire
* Regional Office for [[Asia and the Pacific]], in [[Bangkok]], Thailand
* Regional Office for [[Europe]] and [[Central Asia]], in [[Geneva]], Switzerland
* Regional Office for [[Latin America]] and the [[Caribbean]], in [[Lima]], Peru
* Regional Office for the [[Arab States]], in [[Beirut]], Lebanon

===Sub-regional offices===
Called "Decent Work Technical Support Teams (DWT)", they provide technical support to the work of a number of countries under their area of competence.
[[File:OIT Santiago 20200127 06.jpg|thumb|ILO office in [[Santiago]], Chile]]
* DWT for North Africa, in [[Cairo]], Egypt
* DWT for West Africa, in [[Dakar]], Senegal
* DWT for Eastern and Southern Africa, in [[Pretoria]], South Africa
* DWT for Central Africa, in [[Yaoundé]], Cameroon
* DWT for the Arab States, in Beirut, Lebanon
* DWT for South Asia, in [[New Delhi]], India
* DWT for East and South-East Asia and the Pacific, in Bangkok, Thailand
* DWT for Central and Eastern Europe, in [[Budapest]], Hungary
* DWT for Eastern Europe and Central Asia, in [[Moscow]], Russia
* DWT for the Andean Countries, in Lima, Peru
* DWT for the Caribbean Countries, in [[Port of Spain]], Trinidad and Tobago
* DWT for Central American Countries, in [[San José, Costa Rica]]
* DWT for Countries of the South Cone of Latin America, in [[Santiago]], Chile

===Country and liaison offices===
* In Africa: [[Abidjan]], [[Abuja]], [[Addis Ababa]], [[Algiers]], [[Antananarivo]], Cairo, Dakar, [[Dar es Salaam]], [[Harare]], [[Kinshasa]], [[Lusaka]], Pretoria, Yaoundé
* In the Arab States: Beirut, [[Doha]],<ref>{{cite web|url=https://news.un.org/en/story/2019/10/1049471|title = New labour laws in Qatar benefiting migrant workers a 'momentous step forward': ILO|date = 17 October 2019}}</ref><ref>{{cite web|url=https://www.ilo.org/beirut/media-centre/news/WCMS_627158/lang--en/index.htm|title=ILO inaugurates its first project office in Qatar|date=30 April 2018}}</ref> [[Jerusalem]]
* In Asia and the Pacific: Bangkok, [[Beijing]], [[Colombo]], [[Dhaka]], [[Hanoi]], [[Islamabad]], [[Jakarta]], [[Kabul]], [[Kathmandu]], [[Manila]], New Delhi, [[Suva]], [[Tokyo]], [[Yangon]]
* In Europe and Central Asia: [[Ankara]], [[Berlin]], [[Brussels]], Budapest, [[Lisbon]], [[Madrid]], Moscow, [[Paris]], [[Rome]]
* In the Americas: [[Brasília]], [[Buenos Aires]], [[Mexico City]], [[New York City|New York]], Lima, Port-of-Spain, San José, Santiago, [[Washington, D.C.]]

==Activities==
===Conventions===
{{main|List of International Labour Organization Conventions}}

Through July 2018, the ILO had adopted 189 conventions. If these conventions are ratified by enough governments, they come in force. However, ILO conventions are considered [[international labour standards]] regardless of ratification. When a convention comes into force, it creates a legal obligation for ratifying nations to apply its provisions.

Every year the International Labour Conference's Committee on the Application of Standards examines a number of alleged breaches of international labour standards. Governments are required to submit reports detailing their compliance with the obligations of the conventions they have ratified. Conventions that have not been ratified by member states have the same legal force as recommendations.

In 1998, the 86th International Labour Conference adopted the ''[[Declaration on Fundamental Principles and Rights at Work]]''. This declaration contains four fundamental policies:<ref name="ILO-Declaration">{{cite web |year=1998 |title=ILO Declaration on Fundamental Principles and Rights at Work |url=http://www.ilo.org/declaration/lang--en/index.htm |access-date=16 August 2012 |work=Rights at Work |publisher=International Labour Organization}}</ref>
* The right of workers to associate freely and [[Collective bargaining|bargain collectively]]
* The end of [[Unfree labour|forced and compulsory labour]]
* The end of [[child labour]]
* The end of [[Employment discrimination|unfair discrimination among workers]]

The ILO asserts that its members have an obligation to work towards fully respecting these principles, embodied in relevant ILO conventions. The ILO conventions that embody the fundamental principles have now been ratified by most member states.<ref>See the list of ratifications at [https://archive.today/20120524225645/http://www.ilo.org/ilolex/english/docs/declworld.htm Ilo.org]</ref>

Protocols are always linked to Conventions, even though they are international treaties they do not exist on their own. As with Conventions, Protocols can be ratified.

Recommendations do not have the binding force of conventions and are not subject to ratification. Recommendations may be adopted at the same time as conventions to supplement the latter with additional or more detailed provisions. In other cases recommendations may be adopted separately and may address issues separate from particular conventions.<ref>{{cite web |title=Recommendations |url=http://www.ilo.org/dyn/normlex/en/f?p=NORMLEXPUB:12010:0::NO::: |website=International Labour Organization}}</ref>

=== International Labour Conference ===
Once a year, the ILO organizes the International Labour Conference (ILC) in Geneva to set the broad policies of the ILO, including conventions and recommendations.<ref>{{cite web |title=International Labour Conference |url=http://www.ilo.org/global/about-the-ilo/how-the-ilo-works/international-labour-conference/lang--en/index.htm |access-date=24 May 2012 |publisher=International Labour Organization}}</ref> Also known as the "international parliament of labour", the conference makes decisions about the ILO's general policy, work programme and budget and also elects the Governing Body.

The first conference took place in 1919:<ref name="vittin">Vittin-Balima, C., [https://library.fes.de/pdf-files/gurn/00067.pdf Migrant workers: The ILO standards], archived at ''Bibliothek der Friedrich-Ebert-Stiftung'', accessed 15 December 2023</ref> see [[#Interwar period|Interwar period]] below.

Each member state is represented by a delegation composed of two government delegates, an employer delegate, a worker delegate. All of them have individual voting rights and all votes are equal, regardless of the population of the delegate's member State. The employer and worker delegates are normally chosen in agreement with the most representative national organizations of employers and workers. Usually, the workers and employers' delegates coordinate their voting. All delegates have the same rights and are not required to vote in blocs.

Delegates can attend with advisers and substitute delegates,<ref>ILO, [https://www.ilo.org/wcmsp5/groups/public/---ed_norm/---relconf/documents/meetingdocument/wcms_844627.pdf Final list of delegations, International Labour Conference, 110th Session, 2022], accessed 15 December 2023</ref> and all have the same rights: they can express themselves freely and vote as they wish. This diversity of viewpoints does not prevent decisions from being adopted by very large majorities or [[unanimously]].{{citation needed|date=November 2021}}

Heads of State and prime ministers also participate in the Conference. International organizations, both governmental and others, also attend but as observers.

The 109th session of the International Labour Conference was delayed from 2020 to May 2021 and was held online because of the [[COVID-19 pandemic]]. The first meeting was on 20 May 2021 in [[Geneva]] for the election of its officers. Further sittings were held in June, November and December.<ref>{{cite web |date=17 May 2021 |title=109th International Labour Conference to be held virtually, opening in May |url=https://www.ilo.org/global/about-the-ilo/newsroom/news/WCMS_791932/lang--en/index.htm}}</ref> The 110th session took place from 27 May to 11 June 2022.<ref>ILO, [https://ilo-live-frontend.netlify.app/events/110th-international-labour-conference-2022-05 110th International Labour Conference], accessed 25 September 2022</ref> The 111th session of the International Labour Conference took place in June 2023.<ref>ILO, [https://www.ilo.org/ilc/ILCSessions/111/lang--en/index.htm 111th Session of the International Labour Conference], 5–16 June 2023, accessed 15 December 2023</ref>

===Global forum meetings===
The ILO organizes regular international tripartite gatherings and global dialogue fora on issues of interest to specific sectors of business and employment,<ref>ILO, [https://www.ilo.org/sector/activities/sectoral-meetings/lang--en/index.htm Sectoral meetings], accessed 19 January 2024</ref> for example on [[supply chain]] safety in the packing of [[intermodal container|containers]] for global shipping (2011),<ref>ILO, [https://www.ilo.org/global/docs/WCMS_151472/lang--en/index.htm "Any fool can stuff a container?": ILO to discuss safety in growing container industry], published 14 February 2011, accessed 19 January 2024</ref> and on employment conditions in [[early childhood education]] (2012).<ref>{{Cite book |author=ILO |url= |title=Early childhood education and educators: Global Dialogue Forum on Conditions of Personnel in Early Childhood Education, Geneva, 22–23 February 2012 |publisher=International Labour Office, Sectoral Activities Department |year=2012 |isbn= |location=Geneva}}</ref>

===Labour statistics===
The ILO is a major provider of labour statistics. Labour statistics are an important tool for its member states to monitor their progress toward improving labour standards. As part of their statistical work, ILO maintains several databases.<ref>{{cite web|url=https://www.ilo.org/global/statistics-and-databases/lang--en/index.htm|title=ILO statistics overview|work=International Labour Organization|date=16 April 2024 }}</ref> This database covers 11 major data series for over 200 countries. In addition, ILO publishes a number of compilations of labour statistics, such as the Key Indicators of Labour Markets<ref>{{cite web|url=http://www.ilo.org/empelm/what/WCMS_114240/lang--en/index.htm|title=Key Indicators of the Labour Market (KILM)|work=International Labour Organization|date=11 December 2013 }}</ref> (KILM). KILM covers 20 main indicators on labour participation rates, employment, unemployment, educational attainment, labour cost, and economic performance. Many of these indicators have been prepared by other organizations. For example, the [[Division of international labor comparisons|Division of International Labour Comparisons]] of the [[Bureau of Labor Statistics|U.S. Bureau of Labor Statistics]] prepares the hourly compensation in manufacturing indicator.<ref>{{cite web|url=http://kilm.ilo.org/KILMnetBeta/pdf/kilm17EN-2009.pdf|website=International Labour Organization, KILM 17|title=Hourly compensation costs|access-date=2 June 2012|url-status=dead|archive-url=https://web.archive.org/web/20120711163957/http://kilm.ilo.org/KILMnetBeta/pdf/kilm17EN-2009.pdf|archive-date=11 July 2012}}</ref>

The [[United States Department of Labor|U.S. Department of Labor]] also publishes a yearly report containing a ''[[List of Goods Produced by Child Labor or Forced Labor]]''<ref>{{cite web|url=http://www.dol.gov/ilab/reports/child-labor/list-of-goods/|title=List of Goods Produced by Child Labor or Forced Labor|work=U.S. Department of Labor |access-date=9 January 2015|archive-date=12 January 2021|archive-url=https://web.archive.org/web/20210112004718/https://www.dol.gov/ilab/reports/child-labor/list-of-goods/|url-status=dead}}</ref> issued by the [[Bureau of International Labor Affairs]]. The December 2014 updated edition of the report listed a total of 74 countries and 136 goods.

The ILO is the custodian agency for nine of the 17 indicators of [[Sustainable Development Goal 8]] (SDG 8).<ref>{{Cite book |last=ILO |url=https://www.ilo.org/publications/time-act-sdg-8-integrating-decent-work-sustained-growth-and-environmental-0 |title=Time to act for SDG 8: integrating decent work, sustained growth and environmental integrity |date=2019 |publisher=International Labour Office |isbn=978-92-2-133677-8 |location=Geneva}}</ref>{{Rp|5}}<ref>{{Cite web |date=2024-01-28 |title=Sustainable Development Goal #8: Decent Work and Economic Growth {{!}} International Labour Organization |url=https://www.ilo.org/topics-and-sectors/decent-work-and-2030-agenda-sustainable-development/sustainable-development-goal-8-decent-work-and-economic-growth |access-date=2025-05-06 |website=www.ilo.org |language=en}}</ref> This goal is about "decent work and economic growth".<ref name=":42">{{Cite web |title=United Nations (2018) Economic and Social Council, Conference of European Statisticians, Geneva |url=https://www.unece.org/fileadmin/DAM/stats/documents/ece/ces/2018/CES_39.pdf |access-date=September 19, 2020 |website=United Nations, Geneva}}</ref> For example, ILO is the agency for Indicator 8.b.1 of Target 8.b. The wording of this target is: "By 2020, develop and operationalize a global strategy for youth employment and implement the Global Jobs Pact of the International Labour Organization".<ref name=":172">United Nations (2017) Resolution adopted by the General Assembly on 6 July 2017, [[:File:A RES 71 313 E.pdf|Work of the Statistical Commission pertaining to the 2030 Agenda for Sustainable Development]] ([https://undocs.org/A/RES/71/313 A/RES/71/313])</ref> As such, ILO is in charge of the data gathering for the progress of the Global Youth Empowerment Strategy.<ref name=":43">{{Cite web |title=United Nations (2018) Economic and Social Council, Conference of European Statisticians, Geneva |url=https://www.unece.org/fileadmin/DAM/stats/documents/ece/ces/2018/CES_39.pdf |access-date=September 19, 2020 |website=United Nations, Geneva}}</ref>

===Training and teaching units===

The [[International Training Centre of the International Labour Organization]] (ITCILO) is based in [[Turin]], Italy.<ref>{{cite web|url=http://www.itcilo.org/en|title=ITCILO – International Training Center|last=BIZZOTTO|access-date=21 May 2008|archive-url=https://web.archive.org/web/20150710093243/http://www.itcilo.org/en|archive-date=10 July 2015|url-status=dead}}</ref> Together with the [[University of Turin Department of Law]], the ITC offers training for ILO officers and secretariat members, as well as offering educational programmes. The ITC offers more than 450 training and educational programmes and projects every year for some 11,000 people around the world.

For instance, the ITCILO offers a [[Master of Laws]] programme in management of development, which aims specialize professionals in the field of cooperation and development.<ref>{{cite web|url=http://www.llm-guide.com/university/564/universita-di-torino-turin-university-wipo-worldwide-academy|title=LLM Guide (IP LLM) – University of Torino, Faculty of Law|website=llm-guide.com|access-date=2 June 2012|archive-date=18 March 2016|archive-url=https://web.archive.org/web/20160318082321/http://www.llm-guide.com/university/564/universita-di-torino-turin-university-wipo-worldwide-academy|url-status=dead}}</ref>

== Responses to issues ==

===Child labour===
[[File:Minimum age convention.png|thumb|Parties to ILO's [[Minimum Age Convention, 1973|1973 Minimum Age Convention]], and the minimum ages they have designated: purple, 14 years; green, 15 years; blue, 16 years]][[File:Child labour in Madagascar.jpg|thumb|These young boys are among the millions of children in child labour worldwide. They work at a brickyard in Antsirabe, Madagascar.]][[Child labour]] is often defined as work that deprives children of their childhood, potential, dignity, and is harmful to their physical and mental development. ''Child labour'' refers to work that is mentally, physically, socially or morally dangerous and harmful to children. Further, it can involve interfering with their schooling by depriving them of the opportunity to attend school, obliging them to leave school prematurely, or requiring them to attempt to combine school attendance with excessively long and heavy work.<ref>{{Cite book |title=Ahmady, Kameel 2021:[[Traces of Exploitation in the World of Childhood]] (A Comprehensive Research on Forms, Causes and Consequences of Child Labour in Iran). Avaye Buf Publisher, Denmark.}}</ref><ref>{{Cite web |title=Child labour {{!}} UNICEF |url=https://www.unicef.org/protection/child-labour |access-date=2024-06-10 |website=www.unicef.org |language=en}}</ref><ref>{{Cite web |title=Child labour has a profound impact on the health and wellbeing of children - European Commission |url=https://international-partnerships.ec.europa.eu/news-and-events/stories/child-labour-has-profound-impact-health-and-wellbeing-children_en |access-date=2024-06-10 |website=international-partnerships.ec.europa.eu |language=en}}</ref>

The ILO's [[International Programme on the Elimination of Child Labour]] (IPEC) was created in 1992 with the overall goal of the progressive elimination of child labour, which was to be achieved through strengthening the capacity of countries to deal with the problem and promoting a worldwide movement to combat child labour. The IPEC currently has operations in 88 countries, with an annual expenditure on technical cooperation projects that reached over US$61 million in 2008. It is the largest programme of its kind globally and the biggest single operational programme of the ILO.

The number and range of the IPEC's partners have expanded over the years and now include employers' and workers' organizations, other international and government agencies, private businesses, community-based organizations, NGOs, the media, parliamentarians, the judiciary, universities, religious groups and children and their families.

The IPEC's work to eliminate child labour is an important facet of the ILO's Decent Work Agenda.<ref>{{cite web |url=http://www.ilo.org/global/Themes/Decentwork/lang--en/index.htm |title=Decent work - Themes |access-date=2008-05-21 |url-status=dead |archive-url=https://web.archive.org/web/20080509195231/http://www.ilo.org/global/Themes/Decentwork/lang--en/index.htm |archive-date=9 May 2008}}</ref> Child labour prevents children from acquiring the skills and education they need for a better future.<ref>{{Cite book|last= Von Braun|first=Joachim|editor= Von Braun|title=Employment for poverty reduction and food security|url=https://books.google.com/books?id=7q1ZUsatasIC&pg=PA35|access-date=20 June 2010|series=IFPRI Occasional Papers|year=1995|publisher=Intl Food Policy Res Inst|isbn=978-0-89629-332-8|page=35}}</ref>

The ILO also hosts a Global Conference on the Elimination of Child Labour every four years. The most recent conference was held in Durban, South Africa from 15 to 20 May 2022.<ref>{{Cite web |title=5th Global Conference on the Elimination of Child Labour |url=https://www.5thchildlabourconf.org/en/home |access-date=2022-06-07 |website=www.5thchildlabourconf.org |language=en}}</ref>

The ILO has established the [[World Day Against Child Labour]] on June 12 as an annual event starting in 2002 to raise awareness and prompt action to tackle [[child labour]] worldwide. Coinciding with the [[Sustainable Development Goals]], the event particularly targets the eradication of its worst forms, like slavery and the use of child soldiers, by 2025. The ILO distinguishes between detrimental child labour, which hinders children's development and education, and acceptable work that supports their growth and learning.<ref>{{Cite news |last=Nations |first=United |title=World Day Against Child Labour - Background {{!}} United Nations |url=https://www.un.org/en/observances/world-day-against-child-labour/background |access-date=2024-04-08 |work=United Nations |language=en}}</ref>

In 2023, the World Day's theme, 'Social Justice for All. End Child Labour!', calls for reinvigorated global efforts towards achieving social justice and underscores the critical need for the universal ratification and enforcement of ILO Conventions No. 138 and No. 182 to protect all children from child labour.<ref>{{Cite web |last=Nations |first=United |title=World Day Against Child Labour |url=https://www.un.org/en/observances/world-day-against-child-labour |access-date=2024-04-08 |website=United Nations |language=en}}</ref>

====Exceptions in indigenous communities====
Because of different cultural views involving labour, the ILO developed a series of [[culturally sensitive]] mandates, including convention Nos. 169, 107, 138, and 182, to protect indigenous culture, traditions, and identities. Convention Nos. 138 and 182 lead in the fight against [[child labour]], while Nos. 107 and 169 promote the rights of [[indigenous people|indigenous]] and [[tribal people]]s and protect their right to define their own developmental priorities.<ref name="Larsen">{{cite book|last=Larsen|first=P.B.|title=Indigenous and tribal children: assessing child labour and education challenges.|publisher=International Programme on the Elimination of Child Labour (IPEC), International Labour Office.}}</ref>

In many indigenous communities,{{example needed|date=July 2019}} parents believe that children learn important life lessons through the act of work and through the participation in daily life. Working is seen as a learning process preparing children of the future tasks they will eventually have to do as an adult.<ref>{{cite book|title=Guidelines for Combating Child Labour Among Indigenous Peoples|date=2006|publisher=International Labour Organization|location=Geneva|isbn=978-92-2-118748-6|url=http://www.ilo.org/publns}}</ref> It is a belief that the family's and child well-being and survival is a shared responsibility between members of the whole family. They also see work as an intrinsic part of their child's developmental process. While these attitudes toward [[Child work in indigenous American cultures|child work]] remain, many children and parents from indigenous communities still highly value education.<ref name="Larsen" />

===Forced labour===
[[File:Krychów forced labour camp 1940 (Krowie Bagno).jpg|thumb|Krychów forced labour camp 1940 (Krowie Bagno)]]
The ILO has considered the fight against [[forced labour]] to be one of its main priorities. During the interwar years, the issue was mainly considered a colonial phenomenon, and the ILO's concern was to establish minimum standards protecting the inhabitants of colonies from the worst abuses committed by economic interests.<ref>{{Cite book |last1=Burbank |first1=Jane |url=https://books.google.com/books?id=y7B9euuLEkUC |title=Empires in World History: Power and the Politics of Difference |last2=Cooper |first2=Frederick |date=2010 |publisher=Princeton University Press |isbn=978-0-691-12708-8 |pages=386 |language=en}}</ref> After 1945, the goal became to set a uniform and universal standard, determined by the higher awareness gained during World War II of politically and economically motivated systems of forced labour, but debates were hampered by the Cold War and by exemptions claimed by colonial powers. Since the 1960s, declarations of labour standards as a component of human rights have been weakened by government of postcolonial countries claiming a need to exercise extraordinary powers over labour in their role as emergency regimes promoting rapid economic development.<ref>{{cite journal|author=Daniel Roger Maul|title=The International Labour Organization and the Struggle against Forced Labour from 1919 to the Present|journal=Labor History|year= 2007|volume= 48|issue=4|pages=477–500|doi=10.1080/00236560701580275|s2cid=154924697}}</ref><ref>{{Cite book |title=Solzhenitsyn, Aleksandr.(1973) [[The Gulag Archipelago]]: An Experiment in Literary Investigation. Parisian publisher YMCA-Press.}}</ref>

[[File:Forced Labour Convention map.svg|thumb|Ratifications of the ILO's 1930 [[Forced Labour Convention]], with non-ratifiers shown in red]]

In June 1998, the International Labour Conference adopted a [[Declaration on Fundamental Principles and Rights at Work]] and its follow-up that obligates member states to respect, promote and realize freedom of association and the right to collective bargaining, the elimination of all forms of forced or compulsory labour, the effective abolition of child labour, and the elimination of discrimination in respect of employment and occupation.

[[File:Abolition of Forced Labour Convention.png|thumb|Ratifications of the ILO's 1957 Abolition of Forced Labour Convention, with non-ratifiers shown in red]]In November 2001, following the publication of the InFocus Programme's first global report on forced labour, the ILO's governing body created a special action programme to combat forced labour (SAP-FL),<ref name=":5">{{Cite web |date=2024-01-28 |title=Forced labour, modern slavery and trafficking in persons {{!}} International Labour Organization |url=https://www.ilo.org/topics-and-sectors/forced-labour-modern-slavery-and-trafficking-persons |access-date=2025-05-06 |website=www.ilo.org |language=en}}</ref> as part of broader efforts to promote the 1998 Declaration on Fundamental Principles and Rights at Work and its follow-up. The SAP-FL was created in November 2001 "to tackle the elimination of all forms of forced or compulsory labour, one of its foremost concerns, through both technical assistance and promotional means."<ref>{{cite journal |last1=Plant |first1=Roger |last2=O'Reilly |first2=Caroline |date=March 2003 |title=The ILO's Special Action Programme to Combat Forced Labour |journal=International Labour Review |volume=142 |issue=1 |page=73 |doi=10.1111/j.1564-913X.2003.tb00253.x}}</ref> SAP-FL has developed indicators of forced labour practices<ref>{{cite journal |last1=Chantavanich |first1=Supang |last2=Laodumrongchai |first2=Samarn |last3=Stringer |first3=Christina |date=2016 |title=Under the shadow: Forced labour among sea fishers in Thailand |journal=Marine Policy |language=en |volume=68 |page=6 |bibcode=2016MarPo..68....1C |doi=10.1016/j.marpol.2015.12.015 |issn=0308-597X |s2cid=155418604}}</ref> and published survey reports on forced labour.<ref>{{cite journal |last1=Lerche |first1=Jens |date=October 2007 |title=A Global Alliance against Forced Labour? Unfree Labour, Neo-Liberal Globalization and the International Labour Organization |journal=Journal of Agrarian Change |volume=7 |issue=4 |page=427 |bibcode=2007JAgrC...7..425L |doi=10.1111/j.1471-0366.2007.00152.x |doi-access=free}}</ref>

In 2013, the SAP-FL was integrated into the ILO's ''Fundamental Principles and Rights at Work Branch'' (FUNDAMENTALS)<ref>{{Cite web |date=2024-01-28 |title=Fundamental Principles and Rights at Work Branch (FUNDAMENTALS) {{!}} International Labour Organization |url=https://www.ilo.org/about-ilo/how-ilo-works/organizational-structure-international-labour-office/governance-and-tripartism-department-governance/fundamental-principles-and-rights-work-branch-fundamentals#:~:text=ILO's%20Fundamental%20Principles%20and%20Rights,Rights%20at%20Work%20(DECLARATION). |access-date=2025-05-06 |website=www.ilo.org |language=en}}</ref> bringing together the fight against forced and child labour and working in the context of Alliance 8.7.<ref>{{cite web|url=https://www.alliance87.org/|title=Alliance 8.7|work=alliance87.org}}</ref>

One major tool to fight forced labour was the adoption of the ''ILO Forced Labour Protocol'' by the ''International Labour Conference in 2014''. It was ratified for the second time in 2015 and on 9 November 2016 it entered into force. The new protocol brings the existing ILO Convention 29 on Forced Labour,<ref>{{cite web|url=https://www.ilo.org/dyn/normlex/en/f?p=NORMLEXPUB:12100:0::NO::P12100_ILO_CODE:C029|title=ILO Convention 29}}</ref> adopted in 1930, into the modern era to address practices such as human trafficking. The accompanying Recommendation 203 provides technical guidance on its implementation.<ref>{{cite web|url=https://www.ilo.org/dyn/normlex/en/f?p=NORMLEXPUB:12100:0::NO::P12100_INSTRUMENT_ID:3174688|title=ILO Recommendation 203}}</ref>

In 2015, the ILO launched a global campaign to end modern slavery, in partnership with the International Organization of Employers (IOE) and the International Trade Union Confederation (ITUC). The ''50 for Freedom Campaign'' aims to mobilize public support and encourage countries to ratify the ILO's ''Forced Labour Protocol''.<ref name=":5" />

== Role of Civil Society Organizations in the International Labour Conference ==
Civil society organizations (CSOs) play a supportive and increasingly recognized role in the work of the '''International Labour Organization (ILO)''', particularly in relation to the annual '''International Labour Conference (ILC)'''—the ILO’s highest decision-making body.<ref>{{Cite web |title=ILO Homepage {{!}} International Labour Organization |url=https://www.ilo.org/ |access-date=2025-06-27 |website=www.ilo.org |language=en}}</ref> Through participation in the ILC and other ILO-led initiatives, CSOs contribute to the advancement of labor rights and the promotion of social justice on a global scale.

The ILO encourages engagement with CSOs as part of its tripartite approach to labor governance, which includes representatives from governments, employers, and workers. Civil society actors bring additional perspectives, often representing marginalized groups, informal workers, or specific thematic concerns (e.g., gender equity, forced labor, or child labor).

=== Opportunities for Participation ===
CSOs can engage with the ILO and its annual Conference through several mechanisms:

*Accreditation<ref>{{Cite journal |title= |url=https://webapps.ilo.org/wcmsp5/groups/public/---arabstates/---ro-beirut/documents/genericdocument/wcms_210580.pdf |journal=}}</ref> – CSOs may apply for accreditation to attend the International Labour Conference as observers or participants in side events. Accreditation follows formal procedures established by the ILO and is typically granted to international NGOs or networks with relevant expertise in labor standards and rights.

*Policy Submissions and Reports– Accredited organizations may submit written reports, proposals, and observations relevant to the agenda of the Conference. These contributions inform the deliberations on labor rights, occupational safety, decent work, and social protection.

*Partnership and Collaboration – Beyond the Conference, the ILO maintains ongoing collaboration with CSOs to promote better working conditions, inclusive labor policies, and the implementation of international labor standards. CSOs may partner with the ILO in research, advocacy, technical cooperation, and monitoring initiatives.

More information on the ILO’s engagement with civil society is available at: <nowiki>https://www.ilo.org/partnering-development/civil-society-ilo-partnership</nowiki>

===Minimum wage law===
To protect the right of labours for fixing [[minimum wage]], ILO has created [[Minimum Wage-Fixing Machinery Convention, 1928]], [[Minimum Wage Fixing Machinery (Agriculture) Convention, 1951]] and [[Minimum Wage Fixing Convention, 1970]] as [[minimum wage law]].

=== Commercialized sex ===
From the moment its creation in the [[Treaty of Versailles|1919 Treaty of Versailles]], the ILO has been concerned with the controversial issue of commercial sex. Prior to the creation of the ILO and [[League of Nations]], the issue of sex work had been exclusively under the jurisdiction of the state, now, the ILO and League of Nations believed the issue transcended borders and within their jurisdiction.<ref name=":12">{{Cite journal |last1=Boris |first1=Eileen |last2=Rodriguez Garcia |first2=Magaly |date=Winter 2021 |title=(In)Decent Work: Sex and the ILO |journal=Journal of Women's History |volume=33 |issue=4 |page=197 |doi=10.1353/jowh.2021.0050|s2cid=245127678 |url=https://lirias.kuleuven.be/handle/123456789/685091 |url-access=subscription }}</ref> In the early twentieth, commercialized sex was considered both immoral and criminal activity. Initially, the ILO strongly believed prostitution was linked to vulnerable single working women emigrating to other nations without being under the paternal supervision of a man.<ref name=":12" /> After the widespread destruction caused by [[World War I]], the ILO saw prostitution as spreading contagion requiring regulation.<ref name=":2">{{Cite journal |last1=Boris |first1=Eileen |last2=Garcia |first2=Magaly Rodriguez |date=Winter 2021 |title=(In)Decent Work: Sex and the ILO |journal=Journal of Women's History |volume=33 |issue=4 |page=198 |doi=10.1353/jowh.2021.0050|s2cid=245127678 |url=https://lirias.kuleuven.be/handle/123456789/685091 |url-access=subscription }}</ref> Under the leadership of the French socialist Albert Thomas, the ILO created a medical division whose primary focus was on male sailors whose lives were viewed as "nomadic" and "promiscuous", which made these men susceptible to infection of STD's.<ref name=":2" /> After the conclusion of the Genoa maritime conference in 1920, the ILO proclaimed itself as the critical leader of the prevention and treatment of STD's in sailors. In the interwar years, the ILO also sought to protect female workers in dangers trades, but delegates to ILO Conferences did not consider the sex trade to be "work", which was conceived of as industrial labor.<ref>{{Cite journal |last1=Boris |first1=Eileen |last2=Garcia |first2=Magaly Rodriguez |date=2021 |title=(In)Decent Work: Sex and the ILO |url=https://lirias.kuleuven.be/handle/123456789/685091 |journal=Journal of Women's History |volume=33 |issue=4 |page=200 |doi=10.1353/jowh.2021.0050 |s2cid=245127678|url-access=subscription }}</ref> The ILO believed that if women worked industrial jobs, this would be a deterrent from them living immoral lives. In order to make these industrial jobs more attractive, the ILO promoted better wages and safer working conditions, both intended to prevent women from falling victim to the temptation of the sex trades.<ref>{{Cite journal |last1=Boris |first1=Eileen |last2=Garcia |first2=Magaly Rodriguez |date=Winter 2021 |title=(In)Decent Work: Sex and the ILO |journal=Journal of Women's History |volume=33 |issue=4 |page=201 |doi=10.1353/jowh.2021.0050|s2cid=245127678 |url=https://lirias.kuleuven.be/handle/123456789/685091 |url-access=subscription }}</ref>

Following the creation of the United Nations, the ILO took a back seat to the newly formed organization on the issue of commercialized sex. The [[UN Commission on the Status of Women]] called for abolishing both sex trafficking and prostitution.<ref name=":3">{{Cite journal |last1=Boris |first1=Eileen |last2=Garcia |first2=Magaly Rodriguez |date=Winter 2021 |title=(In)Decent Work: Sex and the ILO |journal=Journal of Women's History |volume=33 |issue=4 |page=202 |doi=10.1353/jowh.2021.0050|s2cid=245127678 |url=https://lirias.kuleuven.be/handle/123456789/685091 |url-access=subscription }}</ref> In the 1950s, the UN Economic and Social Council and the International Police Organization sought to end any activity that resembled slavery, classifying sex trafficking and prostitution as criminal rather than labor issues.<ref name=":3" />

Beginning in 1976, the ILO and other organizations began to examine the working and living conditions of rural women in [[Developing country|developing countries]].<ref name=":62">{{Cite book |last=Garcia |first=Magaly Rodriguez |title=The ILO and the Oldest Non-Profession in The Lifework of a Labor Historian: Essays in Honor of Marcel van der Linden |publisher=Brill |year=2018 |editor-last=Bosma |editor-first=Ulbe |pages=105 |editor-last2=Hofmeester |editor-first2=Karin}}</ref> One example the ILO investigated was the [[Go-go bar|go-go bars]] and the growing phenomenon of ''hired wives'' in Thailand, which both thrived because the development of U.S. military bases in the region.<ref name=":62"/> In the late 1970s, the ILO established the ''Programme on Rural Women'', which investigated the involvement of young masseuses in the sex trade in Bangkok.<ref name=":62"/> It was critical because it was the first time in the history of the ILO or any of its branches that prostitution was described as a form of labor.<ref name=":62"/> In the decades that followed, the increase in [[sex tourism]] and the exploding AIDS epidemic strengthened ILO interest in the commercial sex trade.<ref name=":7">{{Cite book |last=Garcia |first=Magaly Rodriguez |title=The ILO and the Oldest Non-Profession in The Lifework of a Labor Historian: Essays in Honor of Marcel van der Linden |publisher=Brill |year=2018 |editor-last=Bosma |editor-first=Ulbe |pages=106 |editor-last2=Hofmeester |editor-first2=Karin}}</ref>

===HIV/AIDS===
The International Labour Organization (ILO) is the lead [[UN]]-agency on [[HIV]] workplace policies and programmes and private sector mobilization. ILOAIDS<ref>{{cite web|url=http://www.ilo.org/aids/lang--en/index.htm|title=HIV/AIDS and the World of Work Branch (ILOAIDS)|work=International Labour Organization}}</ref> is the branch of the ILO dedicated to this issue.

The ILO has been involved with the HIV response since 1998, attempting to prevent potentially devastating impact on [[Contract labour|labour]] and [[productivity]] and that it says can be an enormous burden for working people, their families and communities. In June 2001, the ILO's governing body adopted a pioneering code of practice on HIV/AIDS and the world of work,<ref>{{cite web|url=http://www.ilo.org/aids/Publications/WCMS_113783/lang--en/index.htm|title=The ILO Code of Practice on HIV/AIDS and the World of Work|work=International Labour Organization|date=June 2001}}</ref> which was launched during a special session of the UN General Assembly.

The same year, ILO became a cosponsor of the [[Joint United Nations Programme on HIV/AIDS]] (UNAIDS).

In 2010, the 99th International Labour Conference adopted the ILO's recommendation concerning HIV and AIDS and the world of work, 2010 (No. 200),<ref>{{cite web|url=http://www.ilo.org/aids/WCMS_142706/lang--en/index.htm|title=Recommendation concerning HIV and AIDS and the World of Work, 2010 (No. 200)|work=International Labour Organization|date=17 June 2010 }}</ref> the first international labour standard on HIV and AIDS. The recommendation lays out a comprehensive set of principles to protect the rights of HIV-positive workers and their families, while scaling up prevention in the workplace. Working under the theme of ''Preventing HIV, Protecting Human Rights at Work'', ILOAIDS undertakes a range of policy advisory, research and technical support functions in the area of HIV and AIDS and the world of work. The ILO also works on promoting social protection as a means of reducing vulnerability to HIV and mitigating its impact on those living with or affected by HIV.

ILOAIDS ran a "Getting to Zero"<ref>{{cite web|url=http://www.ilo.org/aids/Eventsandmeetings/campaign/lang--en/index.htm|title=Getting to Zero|url-status=dead|archive-url=https://web.archive.org/web/20141209165450/http://www.ilo.org/aids/Eventsandmeetings/campaign/lang--en/index.htm|archive-date=9 December 2014}}</ref> campaign to arrive at zero new infections, zero AIDS-related deaths and zero-[[discrimination]] by 2015.<ref>{{cite web|url=http://www.unaids.org/en/aboutunaids/unaidsstrategygoalsby2015|title=UNAIDS|work=unaids.org}}</ref>{{update inline|date=July 2019}} Building on this campaign, ILOAIDS is executing a programme of voluntary and confidential counselling and testing at work, known as VCT@WORK.<ref>{{cite web|url=http://www.ilo.org/aids/WCMS_215899/lang--ja/index.htm|title=VCT@WORK: 5 million women and men workers reached with Voluntary and confidential HIV Counseling and Testing by 2015|work=International Labour Organization|date=December 2014 }}</ref>

===Migrant workers===
As the word "migrant" suggests, [[migrant worker]]s refer to those who moves from one country to another to do their job. For the rights of migrant workers, the first ILC adopted a recommendation on equality and coordination,<ref name=vittin /> and the ILO has adopted conventions, including [[Migrant Workers (Supplementary Provisions) Convention, 1975]] and [[United Nations Convention on the Protection of the Rights of All Migrant Workers and Members of Their Families]] in 1990.<ref>{{Cite journal|last1=Kumaraveloo|first1=K Sakthiaseelan|last2=Lunner Kolstrup|first2=Christina|date=2018-07-03|title=Agriculture and musculoskeletal disorders in low- and middle-income countries|journal=Journal of Agromedicine|language=en|volume=23|issue=3|pages=227–248|doi=10.1080/1059924x.2018.1458671|pmid=30047854|s2cid=51719997|issn=1059-924X}}</ref>

===Domestic workers===
Domestic workers are those who perform a variety of tasks for and in other peoples' homes. For example, they may cook, clean the house, and look after children. Yet they are often the ones with the least consideration, excluded from labour and social protection. This is mainly due to the fact that women have traditionally carried out the tasks without pay.<ref>{{cite web|title=Domestic workers|url=http://www.ilo.org/global/topics/domestic-workers/lang--en/index.htm|publisher=International Labour Organization|access-date=24 May 2012}}</ref> For the rights and [[decent work]] of [[domestic worker]]s including [[migrant domestic workers]], ILO has adopted the [[Convention on Domestic Workers]] on 16 June 2011.

=== Environmental sustainability ===
The ILO has been on working on integrating [[environmental sustainability]] into its activities (or ''greening'' its activities) and the broader discourse since the 1970s. For example, some of ILO's reports in 1972 to 1975 have investigated linkages between [[occupational safety and health]], economic development and [[environmental protection]].<ref name=":0">{{Cite journal |last1=Montesano |first1=Francesco S. |last2=Biermann |first2=Frank |last3=Kalfagianni |first3=Agni |last4=Vijge |first4=Marjanneke J. |date=2023 |title=Can the Sustainable Development Goals Green International Organisations? Sustainability Integration in the International Labour Organisation |journal=Journal of Environmental Policy & Planning |language=en |volume=25 |issue=1 |pages=1–15 |doi=10.1080/1523908X.2021.1976123 |issn=1523-908X |pmc=9893765 |pmid=36744153|bibcode=2023JEPP...25....1M }}</ref> In the 2000s ILO began to promote a "socially just transition to green jobs". The organisation defined [[Green job|green jobs]] as "decent jobs that contribute to preserving and restoring the environment".<ref name=":0" />

Since 2017, the concept of ''[[just transition]]'' has been firmly embedded within the ILO’s position. For example its ''Centenary Declaration for the Future of Work'' in 2019 stated that: "[...] the ILO must direct its efforts to: (i) ensuring a just transition to a future of work that contributes to sustainable development in its economic, social and environmental dimensions".<ref>ILO (2019) [https://www.ilo.org/about-ilo/mission-and-impact-ilo/ilo-centenary-declaration-future-work-2019 ILO Centenary Declaration for the Future of Work]. Adopted at the 108th session of the International Labour Conference</ref>{{Rp|3}} A ''just transition'' focuses on the connection between [[energy transition]] and equitable approaches to [[decarbonization]] that support broader [[Sustainable Development Goals|development goals]].<ref name=":03">{{Cite web |title=How just transition can help deliver the Paris Agreement {{!}} UNDP Climate Promise |url=https://climatepromise.undp.org/research-and-reports/how-just-transition-can-help-deliver-paris-agreement |access-date=2025-02-17 |website=climatepromise.undp.org |language=en}}</ref><ref>{{Cite journal |last1=McCauley |first1=Darren |last2=Heffron |first2=Raphael |date=2018-08-01 |title=Just transition: Integrating climate, energy and environmental justice |url=https://www.sciencedirect.com/science/article/abs/pii/S0301421518302301 |journal=Energy Policy |volume=119 |pages=1–7 |doi=10.1016/j.enpol.2018.04.014 |bibcode=2018EnPol.119....1M |issn=0301-4215 |hdl-access=free |hdl=10023/17583|url-access=subscription }}</ref>

The ILO has also looked at the transition to a [[green economy]], and the [[Green growth#Employment|impact thereof on employment]]. It came to the conclusion a shift to a greener economy could create 24 million [[Employment|new jobs]] globally by 2030, if [[Environmental policy|the right policies]] are put in place. Also, if a transition to a green economy were not to take place, 72 million full-time jobs may be lost by 2030 due to [[heat stress]], and temperature increases will lead to shorter available work hours, particularly in agriculture.<ref>[https://www.un.org/sustainabledevelopment/blog/2019/04/green-economy-could-create-24-million-new-jobs/ Green economy could create 24 million new jobs]</ref><ref>[https://www.ilo.org/global/research/global-reports/weso/greening-with-jobs/lang--en/index.htm Greening with jobs – World Employment and Social Outlook 2018]</ref>

== Awards ==
In 1969, the ILO received the [[Nobel Peace Prize]] for improving [[fraternity]] and peace among nations, pursuing [[decent work]] and [[social justice|justice]] for workers, and providing technical assistance to other developing nations.<ref name="nobel">{{cite web |title=The Nobel Peace Prize 1969 - International Labour Organization Facts |url=https://www.nobelprize.org/prizes/peace/1969/labour/facts/ |access-date=5 July 2006 |work=Nobelprize.org}}</ref><ref>{{Cite web |title=The Nobel Peace Prize 1969 - Presentation Speech |url=https://www.nobelprize.org/prizes/peace/1969/ceremony-speech/ |access-date=2025-05-02 |website=NobelPrize.org |language=en-US}}</ref>

==See also==
* [[Administrative Tribunal of the International Labour Organization]]
* [[Criticism of capitalism]]
* [[Labor theory of value]]
*[[League of Nations archives]]
* [[Seoul Declaration on Safety and Health at Work]], 2008
* [[Social clause]], the integration of seven core ILO labour rights conventions into trade agreements
* [[United Nations Global Compact]], launched in 2000, encouraging businesses to adopt sustainable and socially responsible policies

==References==
{{reflist}}

== External links ==
{{Commons category}}
{{EB1922 Poster}}
* {{official website}}
* [http://www.itcilo.org The International Training Centre of the ILO]
* International Labour Organization, [https://web.archive.org/web/20180807001520/http://blue.lim.ilo.org/cariblex/pdfs/ILO_dec_philadelphia.pdf Declaration of Philadelphia] (1944)

{{United Nations}}
{{Humanitarian partners of the European Commission}}
{{Nobel Peace Prize Laureates 1951-1975}}
{{1969 Nobel Prize winners}}
{{ECOSOC}}
{{Occupational safety and health}}
{{Portal bar|Organized labour|Politics}}
{{Authority control}}

[[Category:International Labour Organization| ]]
[[Category:Global workforce and labor organizations]]
[[Category:Organizations awarded Nobel Peace Prizes]]
[[Category:Organizations established in 1919]]
[[Category:Swiss Nobel laureates]]
[[Category:United Nations Development Group]]
[[Category:United Nations organizations based in Geneva]]
[[Category:United Nations specialized agencies]]
[[Category:Workers' rights organizations]]
[[Category:Human resource management]]
[[Category:Commodification]]
[[Category:Labour movement]]
[[Category:Labour law]]

Aspect ratio

2025-06-24T21:08:10Z

45.232.105.68:

{{Short description|Attribute of a geometric shape}}
{{Other uses}}
{{Use dmy dates|date=January 2024}}
{{More citations needed|date=June 2023}}
The '''aspect ratio''' of a [[geometry|geometric]] shape is the [[ratio]] of its sizes in different dimensions. For example, the aspect ratio of a [[rectangle]] is the ratio of its longer side to its shorter side—the ratio of width to height,<ref>{{Cite web|url=http://whatis.techtarget.com/definition/aspect-ratio |title=What is aspect ratio? |first=Margaret |last=Rouse |date=September 2005 |access-date=3 February 2013 |work=WhatIs? |publisher=TechTarget}}</ref><ref>{{Cite web|url=https://e3displays.com/wide-aspect-ratio-display/ |title=Wide aspect ratio display |first=Margaret |last=Rouse |date=September 2002|access-date=18 February 2020|work=display |publisher=E3displays}}</ref> when the rectangle is oriented as a "[[landscape format|landscape]]".

The aspect ratio is most often expressed as two integer numbers separated by a colon (x:y), less commonly as a simple or decimal [[Fraction (mathematics)|fraction]]. The values x and y do not represent actual widths and heights but, rather, the proportion between width and height. As an example, 8:5, 16:10, 1.6:1, {{Frac|8|5}} and 1.6 are all ways of representing the same aspect ratio.

In objects of more than two dimensions, such as [[hyperrectangle]]s, the aspect ratio can still be defined as the ratio of the longest side to the shortest side.

==Applications and uses==
The term is most commonly used with reference to:
* Graphic / image
** [[Aspect ratio (image)|Image aspect ratio]]
** [[Display aspect ratio]]
** [[Paper size]]
** [[Standard photographic print sizes]]
** [[List of film formats|Motion picture film formats]]
** [[Standard ad size]]
** [[Pixel aspect ratio]]
** [[Photolithography]]: the aspect ratio of an etched, or deposited structure is the ratio of the height of its vertical side wall to its width.
* [[HARMST]] High Aspect Ratios allow the construction of tall microstructures without slant
* [[Tire code]]
* [[Tire sizing]]
* [[Turbocharger]] impeller sizing
* [[Aspect ratio (wing)|Wing aspect ratio]] of an aircraft or bird
* [[Astigmatism (optical systems)|Astigmatism]] of an [[optical lens]]
* Nanorod dimensions
* [[Shape factor (image analysis and microscopy)]]
* [[Finite Element Analysis]]
* Flag design; see [[List of aspect ratios of national flags]]

==Aspect ratios of simple shapes==
===Rectangles===
{{Main|Aspect ratio (image)}}
For a rectangle, the aspect ratio denotes the ratio of the width to the height of the rectangle. A [[square]] has the smallest possible aspect ratio of 1:1.

Examples:
* 4:3 = 1.{{overline|3}}: Some (not all) 20th century computer monitors ([[VGA]], [[XGA]], etc.), [[standard-definition television]]
* <math>\sqrt{2}:1 = 1.414...</math>: international paper sizes ([[ISO 216]])
* 3:2 = 1.5: [[135 film|35mm still camera film]], [[iPhone#Models|iPhone]] (until [[iPhone 5]]) displays
* [[16:10]] = 1.6: commonly used [[widescreen]] [[computer display]]s ([[WXGA (graphics)|WXGA]])
* Φ:1 = 1.618...: [[golden ratio]], close to 16:10
* 5:3 = 1.{{overline|6}}: [[super 16 mm]], a standard [[film gauge]] in many European countries
* 16:9 = 1.{{overline|7}}: [[widescreen]] TV and most laptops
* 2:1 = 2: [[Domino (mathematics)|dominoes]]
* 64:27 = 2.{{overline|370}}: ultra-widescreen, [[21:9 aspect ratio|21:9]]
* 32:9 = 3.{{overline|5}}: super ultra-widescreen

===Ellipses===
For an ellipse, the aspect ratio denotes the ratio of the [[major axis]] to the [[minor axis]]. An ellipse with an aspect ratio of 1:1 is a circle.
[[File:Elps-slr.svg|center]]

==Aspect ratios of general shapes==
In [[geometry]], there are several alternative definitions to aspect ratios of general [[compact set]]s in a d-dimensional space:<ref name=SmithWormald1998>{{Cite book
| last1 = Smith | first1 = W. D.
| last2 = Wormald | first2 = N. C.
| doi = 10.1109/sfcs.1998.743449
| chapter = Geometric separator theorems and applications
| title = Proceedings 39th Annual Symposium on Foundations of Computer Science (Cat. No.98CB36280)
| pages = 232
| year = 1998
| isbn = 0-8186-9172-7
| s2cid = 17962961
| url = http://users.monash.edu.au/~nwormald/papers/geomsep.ps.gz
}}</ref>
* The diameter-width aspect ratio (DWAR) of a compact set is the ratio of its diameter to its width. A circle has the minimal DWAR which is 1. A square has a DWAR of <math>\sqrt{2}</math>.
* The cube-volume aspect ratio (CVAR) of a compact set is the ''d''-th root of the ratio of the ''d''-volume of the smallest enclosing axes-parallel ''d''-cube, to the set's own ''d''-volume. A square has the minimal CVAR which is 1. A circle has a CVAR of <math>\sqrt{2}</math>. An axis-parallel rectangle of width ''W'' and height ''H'', where ''W''>''H'', has a CVAR of <math>\sqrt{W^2/WH} = \sqrt{W/H}</math>.

If the dimension ''d'' is fixed, then all reasonable definitions of aspect ratio are equivalent to within constant factors.

==Notations==
Aspect ratios are mathematically expressed as ''x'':''y'' (pronounced "x-to-y").

Cinematographic aspect ratios are usually denoted as a (rounded) decimal multiple of width vs unit height, while photographic and videographic aspect ratios are usually defined and denoted by whole number ratios of width to height. In [[digital image]]s there is a subtle distinction between the ''display'' aspect ratio (the image as displayed) and the [[Storage aspect ratio|''storage'' aspect ratio]] (the ratio of pixel dimensions); see [[Aspect ratio (image)#Distinctions|Distinctions]].

==See also==
* [[Axial ratio]]
* [[Ratio]]
* [[Equidimensionality|Equidimensional]] ratios in 3D
* [[List of film formats]]
* [[Squeeze mapping]]
* [[Scale (ratio)]]
* [[Vertical orientation]]

==References==
{{Reflist}}

{{Fractions and ratios}}

{{DEFAULTSORT:Aspect Ratio}}
[[Category:Ratios]]

Antiprism

2025-06-24T13:27:33Z

45.232.105.68:

{{Short description|Polyhedron with parallel bases connected by triangles}}
{{more citations needed|date=March 2025}}

[[File:Octagonal antiprism.png|thumb|Octagonal antiprism]]
In [[geometry]], an '''{{nowrap|{{mvar|n}}-gonal}} antiprism''' or {{nowrap|'''{{mvar|n}}-antiprism'''}} is a [[polyhedron]] composed of two [[Parallel (geometry)|parallel]] [[Euclidean group|direct]] copies (not mirror images) of an {{nowrap|{{mvar|n}}-sided}} [[polygon]], connected by an alternating band of {{math|2''n''}} [[triangle]]s. They are represented by the [[Conway polyhedron notation|Conway notation]] {{math|A''n''}}.

Antiprisms are a subclass of [[prismatoid]]s, and are a (degenerate) type of [[snub polyhedron]].

Antiprisms are similar to [[Prism (geometry)|prisms]], except that the bases are twisted relatively to each other, and that the side faces (connecting the bases) are {{math|2''n''}} triangles, rather than {{mvar|n}} [[quadrilateral]]s.

The [[dual polyhedron]] of an {{mvar|n}}-gonal antiprism is an {{mvar|n}}-gonal [[trapezohedron]].

== History ==
In his 1619 book ''[[Harmonices Mundi]]'', [[Johannes Kepler]] observed the existence of the infinite family of antiprisms.<ref>{{cite book|title=Harmonices Mundi|first=Johannes|last=Kepler|author-link=Johannes Kepler|title-link=Harmonices Mundi|year=1619|contribution=Book II, Definition X|language=la|page=49|contribution-url=https://archive.org/details/ioanniskepplerih00kepl/page/n65}} See also [https://archive.org/details/ioanniskepplerih00kepl/page/n75 illustration A], of a heptagonal antiprism.</ref> This has conventionally been thought of as the first discovery of these shapes, but they may have been known earlier: an unsigned printing block for the [[net (geometry)|net]] of a [[hexagonal antiprism]] has been attributed to [[Hieronymus Andreae]], who died in 1556.<ref>{{cite journal
| last1 = Schreiber | first1 = Peter
| last2 = Fischer | first2 = Gisela | author2-link = Gisela Fischer
| last3 = Sternath | first3 = Maria Luise
| date = July 2008
| issue = 4
| journal = Archive for History of Exact Sciences
| jstor = 41134285
| pages = 457–467
| title = New light on the rediscovery of the Archimedean solids during the Renaissance
| volume = 62| doi = 10.1007/s00407-008-0024-z
}}</ref>

The German form of the word "antiprism" was used for these shapes in the 19th century; Karl Heinze credits its introduction to {{ill|Theodor Wittstein|de}}.<ref>{{cite book|title=Genetische Stereometrie|first=Karl|last=Heinze|editor-first=Franz|editor-last=Lucke|publisher=B. G. Teubner|year=1886|language=de|page=14|url=https://books.google.com/books?id=rZALAAAAYAAJ&pg=PA14}}</ref> Although the English "anti-prism" had been used earlier for an [[Prism (optics)|optical prism]] used to cancel the effects of a primary optical element,<ref>{{cite journal
| last = Smyth | first = Piazzi
| doi = 10.1017/s0080456800029112
| issue = 1
| journal = Transactions of the Royal Society of Edinburgh
| pages = 419–425
| title = XVII. On the Constitution of the Lines forming the Low-Temperature Spectrum of Oxygen
| volume = 30
| year = 1881}}</ref> the first use of "antiprism" in English in its geometric sense appears to be in the early 20th century in the works of [[H. S. M. Coxeter]].<ref>{{cite journal
| last = Coxeter | first = H. S. M.
| date = January 1928
| doi = 10.1017/s0305004100011786
| issue = 1
| journal = Mathematical Proceedings of the Cambridge Philosophical Society
| pages = 1–9
| title = The pure Archimedean polytopes in six and seven dimensions
| volume = 24| bibcode = 1928PCPS...24....1C
}}</ref>

==Special cases==
=== Right antiprism ===
For an antiprism with [[Regular polygon|regular {{mvar|n}}-gon]] bases, one usually considers the case where these two copies are twisted by an angle of {{math|{{sfrac|180|''n''}}}} degrees. The axis of a regular polygon is the line [[perpendicular]] to the polygon plane and lying in the polygon centre.

For an antiprism with [[Congruence (geometry)|congruent]] regular {{mvar|n}}-gon bases, twisted by an angle of {{math|{{sfrac|180|''n''}}}} degrees, more regularity is obtained if the bases have the same axis: are ''[[coaxial]]''; i.e. (for non-[[Coplanarity|coplanar]] bases): if the line connecting the base centers is perpendicular to the base planes. Then the antiprism is called a '''right antiprism''', and its {{math|2''n''}} side faces are [[isosceles triangle]]s.<ref name=oh>{{cite book
| last1 = Alsina | first1 = Claudi
| last2 = Nelsen | first2 = Roger B.
| year = 2015
| title = A Mathematical Space Odyssey: Solid Geometry in the 21st Century
| publisher = [[Mathematical Association of America]]
| url = https://books.google.com/books?id=FEl2CgAAQBAJ&pg=PA87
| page = 87
| isbn = 978-1-61444-216-5
| volume = 50
}}</ref>

The [[point groups in three dimensions|symmetry group]] of a right {{mvar|n}}-antiprism is {{math|1=D{{sub|''n''d}}}} of order {{math|4''n''}} known as an [[antiprismatic symmetry]], because it could be obtained by rotation of the bottom half of a prism by <math> \pi/n </math> in relation to the top half. A concave polyhedron created in this way would have this symmetry group, hence prefix "anti" before "prismatic".<ref>{{cite book
| last1 = Flusser | first1 = J.
| last2 = Suk | first2 = T.
| last3 = Zitofa | first3 = B.
| year = 2017
| title = 2D and 3D Image Analysis by Moments
| publisher = [[John Wiley & Sons]]
| isbn = 978-1-119-03935-8
| url = https://books.google.com/books?id=jwKLDQAAQBAJ&pg=PA126
| page = 126
}}</ref> There are two exceptions having groups different than {{math|D''n''d}}:
*{{math|1=''n'' = 2}}: the regular [[tetrahedron]], which has the larger symmetry group {{math|Td}} of order [[List of spherical symmetry groups#Polyhedral symmetry|{{math|24}}]], which has three versions of {{math|D2d}} as subgroups;
*{{math|1=''n'' = 3}}: the regular [[octahedron]], which has the larger symmetry group {{math|Oh}} of order {{math|48}}, which has four versions of {{math|D3d}} as subgroups.<ref>{{cite book
| last1 = O'Keeffe | first1 = Michael
| last2 = Hyde | first2 = Bruce G.
| title = Crystal Structures: Patterns and Symmetry
| year = 2020
| url = https://books.google.com/books?id=_MjPDwAAQBAJ&pg=PA140
| page = 140
| publisher = [[Dover Publications]]
| isbn = 978-0-486-83654-6
}}</ref>
If a right 2- or 3-antiprism is not uniform, then its symmetry group is {{math|D2d}} or {{math|D3d}} as usual. 
The symmetry group contains [[Inversion in a point|inversion]] [[if and only if]] {{mvar|n}} is odd.

The [[Rotation group SO(3)|rotation group]] is {{math|D''n''}} of order {{math|2''n''}}, except in the cases of:
*{{math|1=''n'' = 2}}: the regular tetrahedron, which has the larger rotation group {{math|T}} of order {{math|12}}, which has only one subgroup {{math|D2}};
*{{math|1=''n'' = 3}}: the regular octahedron, which has the larger rotation group {{math|O}} of order {{math|24}}, which has four versions of {{math|D3}} as subgroups.
If a right 2- or 3-antiprism is not uniform, then its rotation group is {{math|D2}} or {{math|D3}} as usual. 
The right {{mvar|n}}-antiprisms have congruent regular {{mvar|n}}-gon bases and congruent isosceles triangle side faces, thus have the same (dihedral) symmetry group as the uniform {{mvar|n}}-antiprism, for {{math|''n'' ≥ 4}}.

=== Uniform antiprism ===
A '''[[Prismatic uniform polyhedron|uniform]] {{mvar|n}}-antiprism''' has two [[Congruence (geometry)|congruent]] [[Regular polygon|''regular'']] {{mvar|n}}-gons as base faces, and {{math|2''n''}} [[Equilateral triangle|''equilateral'']] triangles as side faces. As do uniform prisms, the uniform antiprisms form an infinite class of vertex-transitive polyhedra. For {{math|''n'' {{=}} 2}}, one has the digonal antiprism (degenerate antiprism), which is visually identical to the regular [[tetrahedron]]; for {{math|''n'' {{=}} 3}}, the regular [[octahedron]] is a ''triangular antiprism'' (non-degenerate antiprism).<ref name=oh/>

{{UniformAntiprisms}}

The [[Schlegel diagram]]s of these semiregular antiprisms are as follows:

{| class=wikitable
|- align=center
|[[File:Triangular antiprismatic graph.png|100px]] A3
|[[File:Square antiprismatic graph.png|100px]] A4
|[[File:Pentagonal antiprismatic graph.png|100px]] A5
|[[File:Hexagonal antiprismatic graph.png|100px]] A6
|[[File:Heptagonal antiprism graph.png|100px]] A7
|[[File:Octagonal antiprismatic graph.png|100px]] A8
|}

===Cartesian coordinates===
[[Cartesian coordinates]] for the vertices of a [[#Right antiprism|right]] {{mvar|n}}-antiprism (i.e. with regular {{mvar|n}}-gon bases and {{math|2''n''}} isosceles triangle side faces, circumradius of the bases equal to 1) are:
:<math>\left( \cos\frac{k\pi}{n}, \sin\frac{k\pi}{n}, (-1)^k h \right)</math>

where {{math|0 ≤ ''k'' ≤ 2''n'' – 1}};

if the {{mvar|n}}-antiprism is uniform (i.e. if the triangles are equilateral), then:
<math display=block>2h^2 = \cos\frac{\pi}{n} - \cos\frac{2\pi}{n}.</math>

===Volume and surface area===
Let {{mvar|a}} be the edge-length of a [[Uniform polyhedron|uniform]] {{mvar|n}}-gonal antiprism; then the volume is:
<math display=block>V = \frac{n\sqrt{4\cos^2\frac{\pi}{2n}-1}\sin \frac{3\pi}{2n} }{12\sin^2\frac{\pi}{n}}~a^3,</math>
and the surface area is:
<math display=block>A = \frac{n}{2} \left( \cot\frac{\pi}{n} + \sqrt{3} \right) a^2.</math>
Furthermore, the volume of a regular [[#Right antiprism|right {{mvar|n}}-gonal antiprism]] with side length of its bases {{mvar|l}} and height {{mvar|h}} is given by:{{sfnp|Alsina|Nelsen|2015|p=[http://books.google.com/books?id=FEl2CgAAQBAJ&pg=PA88 88]}}
<math display=block>V = \frac{nhl^2}{12} \left( \csc\frac{\pi}{n} + 2\cot\frac{\pi}{n}\right).</math>

==== Derivation ====
The circumradius of the horizontal circumcircle of the regular <math>n</math>-gon at the base is
:<math>
R(0) = \frac{l}{2\sin\frac{\pi}{n}}.
</math>
The vertices at the base are at
:<math>\left(\begin{array}{c}R(0)\cos\frac{2\pi m}{n} \\ R(0)\sin\frac{2\pi m}{n} \\ 0\end{array}\right),\quad m=0..n-1;</math>
the vertices at the top are at
:<math>\left(\begin{array}{c}R(0)\cos\frac{2\pi (m+1/2)}{n}\\R(0)\sin\frac{2\pi (m+1/2)}{n}\\h\end{array}\right), \quad m=0..n-1.</math>
Via linear interpolation, points on the outer triangular edges of the antiprism that connect vertices at the bottom with vertices at the top
are at
:<math>\left(\begin{array}{c}
\frac{R(0)}{h}[(h-z)\cos\frac{2\pi m}{n}+z\cos\frac{\pi(2m+1)}{n}]\\
\frac{R(0)}{h}[(h-z)\sin\frac{2\pi m}{n}+z\sin\frac{\pi(2m+1)}{n}]\\
\\z\end{array}\right), \quad 0\le z\le h, m=0..n-1</math>
and at
:<math>\left(\begin{array}{c}
\frac{R(0)}{h}[(h-z)\cos\frac{2\pi (m+1)}{n}+z\cos\frac{\pi(2m+1)}{n}]\\
\frac{R(0)}{h}[(h-z)\sin\frac{2\pi (m+1)}{n}+z\sin\frac{\pi(2m+1)}{n}]\\
\\z\end{array}\right), \quad 0\le z\le h, m=0..n-1.</math>
By building the sums of the squares of the <math>x</math> and <math>y</math> coordinates in one of the previous two vectors,
the squared circumradius of this section at altitude <math>z</math> is
:<math>
R(z)^2 = \frac{R(0)^2}{h^2}[h^2-2hz+2z^2+2z(h-z)\cos\frac{\pi}{n}].
</math>
The horizontal section at altitude <math>0\le z\le h</math> above the base is a <math>2n</math>-gon (truncated <math>n</math>-gon)
with <math>n</math> sides of length <math>l_1(z)=l(1-z/h)</math> alternating with <math>n</math> sides of length <math>l_2(z)=lz/h</math>.
(These are derived from the length of the difference of the previous two vectors.)
It can be dissected into <math>n</math> isoceless triangles of edges <math>R(z),R(z)</math> and <math>l_1</math> (semiperimeter <math>R(z)+l_1(z)/2</math>)
plus <math>n</math>
isoceless triangles of edges <math>R(z),R(z)</math> and <math>l_2(z)</math> (semiperimeter <math>R(z)+l_2(z)/2</math>).
According to Heron's formula the areas of these triangles are
:<math>
Q_1(z) = \frac{R(0)^2}{h^2} (h-z)\left[(h-z)\cos\frac{\pi}{n}+z\right] \sin\frac{\pi}{n}
</math>
and
:<math>
Q_2(z) =
\frac{R(0)^2}{h^2} z\left[z\cos\frac{\pi}{n}+h-z\right] \sin\frac{\pi}{n}
.
</math>
The area of the section is <math>n[Q_1(z)+Q_2(z)]</math>, and the volume is
:<math>
V = n\int_0^h [Q_1(z)+Q_2(z)] dz
= \frac{nh}{3}R(0)^2\sin\frac{\pi}{n}(1+2\cos\frac{\pi}{n})
= \frac{nh}{12}l^2\frac{1+2\cos\frac{\pi}{n}}{\sin\frac{\pi}{n}}
.
</math>

The volume of a right {{mvar|n}}-gonal [[Prism (geometry)|prism]] with the same {{mvar|l}} and {{mvar|h}} is:
<math display=block>V_{\mathrm{prism}}=\frac{nhl^2}{4} \cot\frac{\pi}{n}</math>
which is smaller than that of an antiprism.

== Generalizations ==
===In higher dimensions===
Four-dimensional antiprisms can be defined as having two [[dual polyhedra]] as parallel opposite faces, so that each [[Cell (geometry)|three-dimensional face]] between them comes from two dual parts of the polyhedra: a vertex and a dual polygon, or two dual edges. Every three-dimensional convex polyhedron is combinatorially equivalent to one of the two opposite faces of a four-dimensional antiprism, constructed from its [[canonical polyhedron]] and its polar dual.<ref>{{cite journal | last = Grünbaum | first = Branko | author-link = Branko Grünbaum | issue = 2 | journal = Geombinatorics | mr = 2298896 | pages = 69–78 | title = Are prisms and antiprisms really boring? (Part 3) | url = https://faculty.washington.edu/moishe/branko/BG256.Prisms%20and%20antiprisms.%20Part%203.pdf | volume = 15 | year = 2005}}</ref> However, there exist four-dimensional polychora that cannot be combined with their duals to form five-dimensional antiprisms.<ref>{{cite journal | last = Dobbins | first = Michael Gene | doi = 10.1007/s00454-017-9874-y | issue = 4 | journal = [[Discrete & Computational Geometry]] | mr = 3639611 | pages = 966–984 | title = Antiprismlessness, or: reducing combinatorial equivalence to projective equivalence in realizability problems for polytopes | volume = 57 | year = 2017}}</ref>

===Self-crossing polyhedra===
{{unreferenced section|date=April 2025}}
{{Further|Prismatic uniform polyhedron}}
{| class="wikitable floatright" width=320
|- align=center
| [[File:Crossed-triangular_prism.png|80px]] [[crossed triangular antiprism|3/2-antiprism]] nonuniform

| [[File:Crossed pentagonal antiprism.png|80px]] 5/4-antiprism nonuniform

|[[File:Pentagrammic antiprism.png|100px]] 5/2-antiprism
|[[File:Pentagrammic crossed antiprism.png|100px]] 5/3-antiprism
|- align=center
|[[Image:Antiprism 9-2.png|100px]] 9/2-antiprism
|[[Image:Antiprism 9-4.png|100px]] 9/4-antiprism
|[[Image:Antiprism 9-5.png|100px]] 9/5-antiprism
|}

[[File:Antiprisms.pdf|thumb|All the non-star and star uniform antiprisms up to 15 sides, together with those of a 29-gon (or [[List of polygons#List of n-gons by Greek numerical prefixes|icosaenneagon]]). For example, the icosaenneagrammic crossed antiprism ({{math|29/''q''}}) with the greatest {{math|''q''}}, such that it can be uniform, has {{math|''q'' {{=}} 19}} and is depicted at the bottom right corner of the image. For {{math|''q'' ≥ 20}} up to {{math|28}} the crossed antiprism cannot be uniform. Note: Octagrammic crossed antiprism (8/5) is missing.]]
Uniform star antiprisms are named by their [[star polygon]] bases, {{math|{''p''/''q''},}} and exist in prograde and in retrograde (crossed) solutions. Crossed forms have intersecting [[vertex figure]]s, and are denoted by "inverted" fractions: {{math|''p''/(''p'' – ''q'')}} instead of {{math|''p''/''q''}}; example: (5/3) instead of (5/2).

A '''right star {{math|''n''}}-antiprism''' has two [[Congruence (geometry)|congruent]] [[#Right antiprism|coaxial]] [[Regular polygon|regular]] [[Convex polytope|'''''convex''''']] or [[Star polygon|'''''star''''']] polygon base faces, and {{math|2''n''}} [[isosceles triangle]] side faces.

Any star antiprism with ''regular'' convex or star polygon bases can be made a ''right'' star antiprism (by translating and/or twisting one of its bases, if necessary).

In the retrograde forms, but not in the prograde forms, the triangles joining the convex or star bases intersect the axis of rotational symmetry. Thus:

*Retrograde star antiprisms with regular convex polygon bases cannot have all equal edge lengths, and so cannot be uniform. "Exception": a retrograde star antiprism with equilateral triangle bases (vertex configuration: 3.3/2.3.3) can be uniform; but then, it has the appearance of an equilateral triangle: it is a degenerate star polyhedron.
*Similarly, some retrograde star antiprisms with regular star polygon bases cannot have all equal edge lengths, and so cannot be uniform. Example: a retrograde star antiprism with regular star {{mset|7/5}}-gon bases (vertex configuration: 3.3.3.7/5) cannot be uniform.

Also, star antiprism compounds with regular star {{math|{{mset|''p''/''q''}}}}-gon bases can be constructed if {{mvar|p}} and {{mvar|q}} have common factors. Example: a star (10/4)-antiprism is the compound of two star (5/2)-antiprisms.

====Number of uniform crossed antiprisms====
If the notation {{math|(''p''/''q'')}} is used for an antiprism, then for {{math|''q'' > ''p''/2}} the antiprism is crossed (by definition) and for {{math|''q'' < ''p''/2}} is not. In this section all antiprisms are assumed to be non-degenerate, i.e. {{math|''p'' ≥ 3}}, {{math|''q'' ≠ ''p''/2}}. Also, the condition {{math|(''p'',''q'') {{=}} 1}} ({{mvar|p}} and {{mvar|q}} are relatively prime) holds, as compounds are excluded from counting. The number of uniform crossed antiprisms for fixed {{mvar|p}} can be determined using simple inequalities. The condition on possible {{mvar|q}} is

: {{math|{{sfrac|''p''|2}} < ''q'' < {{sfrac|2|3}} ''p''}} and {{math|1=(''p'',''q'') = 1.}}

Examples:
* {{mvar|''p''}} = 3: 2 ≤ {{mvar|q}} ≤ 1 – a uniform triangular crossed antiprism does not exist.
* {{mvar|''p''}} = 5: 3 ≤ {{mvar|q}} ≤ 3 – one antiprism of the type (5/3) can be uniform.
* {{mvar|''p''}} = 29: 15 ≤ {{mvar|q}} ≤ 19 – there are five possibilities (15 thru 19) shown in the rightmost column, below the (29/1) convex antiprism, on the image above.
* {{mvar|''p''}} = 15: 8 ≤ {{mvar|q}} ≤ 9 – antiprism with {{mvar|q}} = 8 is a solution, but {{mvar|q}} = 9 must be rejected, as (15,9) = 3 and {{sfrac|15|9}} = {{sfrac|5|3}}. The antiprism (15/9) is a compound of three antiprisms (5/3). Since 9 satisfies the inequalities, the compound can be uniform, and if it is, then its parts must be. Indeed, the antiprism (5/3) can be uniform by example 2.

In the first column of the following table, the symbols are Schoenflies, Coxeter, and orbifold notation, in this order.
{| class="wikitable mw-collapsible mw-collapsed" style="text-align:center"
|+ class="nowrap"| Star ({{math|''p''/''q''}})-antiprisms by symmetry, for {{math|''p'' ≤ 12}}
! [[List of spherical symmetry groups|Symmetry group]]
! colspan=4 | Uniform stars
! Right stars
|-
! {{math|D3h [2,3] (2*3)}}
| colspan=4 |
| [[Image:Crossed triangular antiprism.svg|64px]] 3.3/2.3.3 [[Crossed triangular antiprism]]
|-
! {{math|D4d [2+,8] (2*4)}}
| colspan=4 |
| [[Image:Crossed square antiprism.png|64px]] 3.3/2.3.4 [[Crossed square antiprism]]
|-
! {{math|D5h [2,5] (*225)}}
| [[Image:Pentagrammic antiprism.png|64px]] 3.3.3.5/2 [[Pentagrammic antiprism]]
| colspan=3 |
| [[Image:Crossed pentagonal antiprism.png|64px]] 3.3/2.3.5 [[Crossed pentagonal antiprism]]
|-
! {{math|D5d [2+,10] (2*5)}}
| [[Image:Pentagrammic crossed antiprism.png|64px]] 3.3.3.5/3 [[Pentagrammic crossed-antiprism]]
|-
! {{math|D6d [2+,12] (2*6)}}
| colspan=4 |
| [[Image:Crossed hexagonal antiprism.png|64px]] 3.3/2.3.6 [[Crossed hexagonal antiprism]]
|-
! {{math|D7h [2,7] (*227)}}
| [[Image:Antiprism 7-2.png|64px]] 3.3.3.7/2 Heptagrammic antiprism (7/2)
| [[Image:Antiprism 7-4.png|64px]] 3.3.3.7/4 Heptagrammic crossed antiprism (7/4)
|-
! {{math|D7d [2+,14] (2*7)}}
| [[Image:Antiprism 7-3.png|64px]] 3.3.3.7/3 Heptagrammic antiprism (7/3)
|-
! {{math|D8d [2+,16] (2*8)}}
| [[Image:Antiprism 8-3.png|64px]] 3.3.3.8/3 [[Octagrammic antiprism]]
| [[Image:Antiprism 8-5.png|64px]] 3.3.3.8/5 [[Octagrammic crossed-antiprism]]
|-
! {{math|D9h [2,9] (*229)}}
| [[Image:Antiprism 9-2.png|64px]] 3.3.3.9/2 [[Enneagrammic antiprism (9/2)]]
| [[Image:Antiprism 9-4.png|64px]] 3.3.3.9/4 [[Enneagrammic antiprism (9/4)]]
|-
! {{math|D9d [2+,18] (2*9)}}
| [[Image:Antiprism 9-5.png|64px]] 3.3.3.9/5 [[Enneagrammic crossed-antiprism]]
|-
! {{math|D10d [2+,20] (2*10)}}
| [[Image:Antiprism 10-3.png|64px]] 3.3.3.10/3 [[Decagrammic antiprism]]
|-
! {{math|D11h [2,11] (*2.2.11)}}
| [[Image:Antiprism 11-2.png|64px]] 3.3.3.11/2 Undecagrammic (11/2)
| [[Image:Antiprism 11-4.png|64px]] 3.3.3.11/4 Undecagrammic (11/4)
| [[Image:Antiprism 11-6.png|64px]] 3.3.3.11/6 Undecagrammic crossed (11/6)
|-
! {{math|D11d [2+,22] (2*11)}}
| [[Image:Antiprism 11-3.png|64px]] 3.3.3.11/3 Undecagrammic (11/3)
| [[Image:Antiprism 11-5.png|64px]] 3.3.3.11/5 Undecagrammic (11/5)
| [[Image:Antiprism 11-7.png|64px]] 3.3.3.11/7 Undecagrammic crossed (11/7)
|-
! {{math|D12d [2+,24] (2*12)}}
| [[Image:Antiprism 12-5.png|64px]] 3.3.3.12/5 Dodecagrammic
| [[Image:Antiprism 12-7.png|64px]] 3.3.3.12/7 Dodecagrammic crossed
|-
! ...
| ...
|}

== See also ==
* [[Antiprism graph]], graph of an antiprism
*[[Grand antiprism]], a four-dimensional polytope
*[[Skew polygon]], a three-dimensional polygon whose convex hull is an antiprism

== References ==
{{reflist}}

==Further reading==
*{{cite book | author= Anthony Pugh | year= 1976 | title= Polyhedra: A visual approach | publisher= University of California Press Berkeley | location= California | isbn= 0-520-03056-7 }} Chapter 2: Archimedean polyhedra, prisms and antiprisms

==External links==
*{{Commons category-inline}}
*{{MathWorld|urlname=Antiprism|title=Antiprism}}

{{Polyhedron navigator}}

[[Category:Uniform polyhedra]]
[[Category:Prismatoid polyhedra]]

Ice skating

2025-06-23T18:16:05Z

45.232.105.68:

{{Short description|Self-propulsion of a person over ice, wearing bladed skates}}
{{More citations needed|date=August 2013}}
{{Use dmy dates|date=February 2019}}
[[File:Skating, man, woman, ice-skating rink, winter, smile, free time Fortepan 14348.jpg|thumb|Outdoor ice skaters in 1925|260x260px]]
[[File:DBP_1994_Tag_der_Briefmarke.jpg|thumb|A postman in Germany during the winter of 1900 (stamp from 1994)|173x173px]]
'''Ice skating''' is the [[Human-powered transport|self-propulsion]] and gliding of a person across an [[ice]] surface, using metal-bladed [[ice skate]]s. People skate for various reasons, including recreation (fun), exercise, competitive sports, and [[commuting]]. Ice skating may be performed on naturally frozen bodies of water, such as ponds, lakes, canals, and rivers, and on human-made ice surfaces both indoors and outdoors.

Natural ice surfaces used by skaters can accommodate a variety of winter sports which generally require an enclosed area, but are also used by skaters who need [[Ice rink#Tracks and trails|ice tracks and trails]] for [[Tour skating|distance skating]] and [[speed skating]]. Man-made ice surfaces include [[ice rink]]s, [[ice hockey rink]]s, [[bandy field]]s, ice tracks required for the sport of [[ice cross downhill]], and [[arena]]s.

Various formal sports involving ice skating have emerged since the 19th century. [[Ice hockey]], [[bandy]], [[rinkball]], and [[ringette]] are team sports played with, respectively, a flat sliding puck, a ball, and a rubber ring. [[Synchronized skating]] is a unique artistic team sport derived from [[figure skating]]. Figure skating, [[ice cross downhill]], [[speed skating]], and [[barrel jumping]] (a discipline of speed skating) are among the sporting disciplines for individuals.

==History==
===Early history of ice skating===
[[File:SCENEONICE.jpg|thumb|''Skating fun'' by 17th century Dutch painter Hendrick Avercamp|200x200px]]Research<ref>[http://news.nationalgeographic.com/news/2008/01/080104-first-skates.html Bone Ice Skates Invented by Ancient Finns, Study Says] {{webarchive|url=https://web.archive.org/web/20140221131850/http://news.nationalgeographic.com/news/2008/01/080104-first-skates.html |date=2014-02-21 }}, nationalgeographic.com</ref> suggests that the earliest ice skating happened in southern [[Finland]] more than 4,000 years ago. This was done to save energy during winter journeys. True skating emerged when a steel blade with sharpened edges was used. Skates now cut into the ice instead of gliding on top of it. The [[Netherlands|Dutch]] added edges to [[ice skate]]s in the 13th or 14th century. These ice skates were made of steel, with sharpened edges on the bottom to aid movement.<ref>{{cite book |last=Brokaw |first=Irving |title=The Art of Skating: Its History and Development, with Practical Directions |url=https://books.google.com/books?id=F8lMAAAAYAAJ |year=1910 |publisher=Letchworth at the Arden Press & Fetter Lane |page=[https://books.google.com/books?id=F8lMAAAAYAAJ&pg=PA12 12] |access-date=6 May 2019 |archive-date=13 April 2023 |archive-url=https://web.archive.org/web/20230413055940/https://books.google.com/books?id=F8lMAAAAYAAJ |url-status=live }}</ref>

The fundamental construction of modern ice skates has stayed largely the same since then, although differing greatly in the details, particularly in the method of binding and the shape and construction of the steel blades. In the [[Netherlands]], ice skating was considered proper for all classes of people, as shown in many pictures from [[Dutch Golden Age painter]]s.

Ice skating was also practiced in China during the [[Song dynasty]], and became popular among the ruling family of the [[Qing dynasty]].<ref name=pdo130220/> Ancient ice skates, made of animal bones, were found at the bronze age Gaotai Ruins in [[North West China|north west China]], and are estimated to be likely 3,500 years old. Archeologists say these ancient skates are "clear evidence for communication between [[China]] and [[Europe]]" in the [[Bronze Age Europe|Bronze Age era]], as they are very similar to bone skates unearthed in Europe.<ref>{{Cite web |date=2023-03-02 |title=Animal Bone Ice Skates Dating Back 3,500 Years Found In China |url=https://www.iflscience.com/animal-bone-ice-skates-dating-back-3-500-years-found-in-china-67780 |access-date=2023-06-10 |website=IFLScience |language=en}}</ref><ref>{{Cite web |author1=Tom Metcalfe |date=2023-03-07 |title=Bronze Age ice skates with bone blades discovered in China |url=https://www.livescience.com/bronze-age-ice-skates-with-bone-blades-discovered-in-china |access-date=2023-06-10 |website=livescience.com |language=en}}</ref>

===Rising popularity and first clubs===
[[File:Reverend Robert Walker (1755 - 1808) Skating on Duddingston Loch.jpg|thumb|''[[The Skating Minister]]'' by [[Henry Raeburn]], depicting a member of the [[Edinburgh Skating Club]] in the 1790s|208x208px]]
In England "the London boys" had improvised butcher's bones as skates since the 12th century. Skating on metal skates seems to have arrived in England at the same time as the [[garden canal]], with the [[English Restoration]] in 1660, after the king and court returned from an exile largely spent in the Netherlands. In London the ornamental "canal" in [[St James's Park]] was the main centre until the 19th century. Both [[Samuel Pepys]] and [[John Evelyn]], the two leading diarists of the day, saw it on the "new canal" there on 1 December 1662, the first time Pepys had ever seen it ("a very pretty art"). Then it was "performed before their Majesties and others, by diverse gentlemen and others, with scheets after the manner of the Hollanders". Two weeks later, on 15 December 1662, Pepys accompanied the Duke of York, later King [[James II of England|James II]], on a skating outing: "To the Duke, and followed him in the Park, when, though the ice was broken, he would go slide upon his skates, which I did not like; but he slides very well." In 1711 [[Jonathan Swift]] still thinks the sport might be unfamiliar to [[Esther Johnson|his "Stella"]], writing to her: "Delicate walking weather; and the Canal and Rosamund's Pond full of the rabble and with skates, ''if you know what that is''."<ref>[[Jacob Larwood|Larwood, Jacob]], ''St. James's Park'', Vol. 2 of ''The Story of the London Parks'', 118-119, 1872, Hotwood, [https://books.google.com/books?id=pxEHAAAAQAAJ&dq=skating+St+James's+Park+canal&pg=PA118 google books] {{Webarchive|url=https://web.archive.org/web/20230413055955/https://books.google.com/books?id=pxEHAAAAQAAJ&dq=skating+St+James%27s+Park+canal&pg=PA118 |date=13 April 2023 }}. Larwood notes that Rosamund's Pond was also in St James's Park, see pp. 85 (map), 87.</ref><ref>{{cite journal |last=Adams |first=Mary Louise |title=The manly history of a 'girls' sport': Gender, class and the development of nineteenth-century figure skating |journal=International Journal of the History of Sport |year=2007 |volume=24 |issue=7 |pages=872–838 |doi=10.1080/09523360701311752 |s2cid=143833638 |via=Taylor & Francis}}</ref>

The first organised [[figure skating club|skating club]] was the [[Edinburgh Skating Club]], formed in the 1740s; some claim the club was established as early as 1642.<ref name="skating">"In The Beginning...", ''Skating'' magazine, Jun 1970</ref><ref>{{cite web |url=https://www.iceskating.org.uk/about-ice-skating |title=A Brief History of Ice and the National Ice Skating Association of Great Britain |last=Bird |first=Denis L. |publisher=[[British Ice Skating|NISA]] |access-date=28 October 2014 |archive-date=5 October 2021 |archive-url=https://web.archive.org/web/20211005170117/https://www.iceskating.org.uk/about-ice-skating |url-status=live }}</ref><ref>{{cite encyclopedia |url=https://www.thecanadianencyclopedia.ca/en/article/figure-skating |title=Figure Skating |date=2011 |encyclopedia=[[The Canadian Encyclopedia]] |access-date=15 July 2021 |archive-date=26 July 2021 |archive-url=https://web.archive.org/web/20210726173625/https://www.thecanadianencyclopedia.ca/en/article/figure-skating |url-status=live }}</ref>[[File:Adam van Breen, Skating on the Frozen Amstel River, 1611, NGA 150754.jpg|thumb|Adam van Breen, ''Skating on the Frozen Amstel River'', 1611, [[National Gallery of Art]]|201x201px|left]]An early contemporary reference to the club appeared in the second edition (1783) of the [[Encyclopædia Britannica]]:

{{Blockquote|The metropolis of Scotland has produced more instances of elegant skaters than perhaps any country whatever: and the institution of a skating club about 40 years ago has contributed not a little to the improvement of this elegant amusement.<ref name="skating"/>}}[[File:Z zabawy na lodzie odbytej d. 26 lutego r. b. - Rysował C. Jankowski (59016).jpg|thumb|Ice skating party in [[Warsaw]] in the 1880s|235x235px]]From this description and others, it is apparent that the form of skating practiced by club members was indeed an early form of [[figure skating]] rather than [[speed skating]]. For admission to the club, candidates had to pass a skating test where they performed a complete circle on either foot (e.g., a [[compulsory figures|figure eight]]), and then jumped over first one hat, then two and three, placed over each other on the ice.<ref name="skating" />

On the [[Continental Europe|Continent]], participation in ice skating was limited to members of the upper classes. Emperor [[Rudolf II, Holy Roman Emperor|Rudolf II]] of the [[Holy Roman Empire]] enjoyed ice skating so much, he had a large ice carnival constructed in his court in order to popularise the sport. King [[Louis XVI]] of France brought ice skating to [[Paris]] during his reign. [[Madame de Pompadour]], [[Napoleon I]], [[Napoleon III]], and the [[House of Stuart]] were, among others, royal and upper-class fans of ice skating.{{cn|date=May 2025}}

The next skating club to be established was in [[London]] and was not founded until 1830.<ref name="skating"/> Members wore a silver skate hanging from their buttonhole and met on The Serpentine, [[Hyde Park, London|Hyde Park]] on 27 December 1830.<ref>{{cite news|title= Skaiting Club|newspaper= Bristol Mirror|date= 1 January 1831|page= 1}}</ref>
By the mid-19th century, ice skating was a popular pastime among the British upper and middle classes. [[Queen Victoria]] became acquainted with her future husband, [[Albert, Prince Consort|Prince Albert]], through a series of ice skating trips.<ref>{{cite web |url=http://www.followthebrownsigns.com/ice-skating/ |title=Ice Skating |website=followthebrownsigns.com |access-date=28 October 2014 |url-status=live |archive-url=https://web.archive.org/web/20141028155237/http://www.followthebrownsigns.com/ice-skating/ |archive-date=28 October 2014}}</ref> Albert continued to skate after their marriage and on falling through the ice was once rescued by Victoria and a lady in waiting from a stretch of water in the grounds of [[Buckingham Palace]].<ref>{{cite news|title= British News|newspaper= The Atlas |date= 13 February 1841|page= 5}}</ref>

[[File:Glaciarium Ice Rink.jpg|thumb|left|Interior of the [[Glaciarium]] in 1876|200x200px]]Early attempts at the construction of artificial ice rinks were made during the "rink mania" of 1841–44. As the technology for the maintenance of natural ice did not exist, these early rinks used a substitute consisting of a mixture of hog's [[lard]] and various salts. An item in the 8 May 1844 issue of Littell's 'Living Age' headed the '[[Glaciarium]]' reported that "This establishment, which has been removed to Grafton Street East' [[Tottenham Court Road]], was opened on Monday afternoon. The area of artificial ice is extremely convenient for such as may be desirous of engaging in the graceful and manly pastime of skating."
{{Clear}}

===Emergence as a sport===
[[File:Fenskaters ronden ton.jpg|thumb|19th-century [[fen skating]]|200x200px]]
Skating became popular as a recreation, a means of transport and spectator sport in [[fen skating|The Fens]] in England for people from all walks of life. Racing was the preserve of workers, most of them agricultural labourers. It is not known when the first skating matches were held, but by the early nineteenth century racing was well established and the results of matches were reported in the press.<ref name="Handbook">{{cite book |title=Handbook of Fen Skating |year=1882 |last1=Goodman |first1=Neville |last2=Goodman |first2=Albert |publisher=Longmans, Green and Co. |url=https://archive.org/details/handbookfenskat00goodgoog |ol=25422698M |location=London |access-date=15 March 2013 |url-status=live |archive-url=https://web.archive.org/web/20150610205539/https://archive.org/details/handbookfenskat00goodgoog |archive-date=10 June 2015}}</ref> Skating as a sport developed on the lakes of Scotland and the canals of the [[Netherlands]]. In the 13th and 14th centuries wood was substituted for bone in skate blades, and in 1572 the first iron skates were manufactured.<ref name="Ice Skating">{{cite web |last=Greiff |first=James |title=History of Ice Skating |url=https://www.scholastic.com/teachers/articles/teaching-content/ice-skating/ |publisher=[[Scholastic Corporation]] |access-date=26 February 2014 |url-status=live |archive-url=https://web.archive.org/web/20171229172243/https://www.scholastic.com/teachers/articles/teaching-content/ice-skating/ |archive-date=29 December 2017}}</ref> When the waters froze, skating matches were held in towns and villages all over the Fens. In these local matches men (or sometimes women or children) would compete for prizes of money, clothing, or food.<ref name="Cycling, 19 January 1895, p 19">''Cycling'', 19 January 1895, p 19.</ref>

The winners of local matches were invited to take part in the grand or championship matches, in which skaters from across the Fens would compete for cash prizes in front of crowds of thousands. The championship matches took the form of a Welsh main or "last man standing" contest ([[single-elimination tournament]]). The competitors, 16 or sometimes 32, were paired off in heats and the winner of each heat went through to the next round. A course of 660 yards was measured out on the ice, and a barrel with a flag on it placed at either end. For a one-and-a-half-mile race the skaters completed two rounds of the course, with three barrel turns.<ref name="Cycling, 19 January 1895, p 19"/>

[[File:Fen Runners.jpg|thumb|left|Fen runners|200x200px]]
In the Fens, skates were called [[patten (shoe)#Other uses of the term|pattens]], fen runners, or [[Whittlesey]] runners. The footstock was made of [[Beech tree|beechwood]]. A screw at the back was screwed into the heel of the boot, and three small spikes at the front kept the skate steady. There were holes in the footstock for leather straps to fasten it to the foot. The metal blades were slightly higher at the back than the front. In the 1890s, fen skaters started to race in Norwegian style skates.

On Saturday 1 February 1879, a number of professional ice skaters from [[Cambridgeshire]] and [[Huntingdonshire]] met in the Guildhall, Cambridge, to set up the [[National Ice Skating Association|National Skating Association]], the first national ice skating body in the world.<ref>{{cite web |url=https://www.iceskating.org.uk/node/6297 |title=The History of Long Track Speed Skating |publisher=[[British Ice Skating|NISA]] |date=18 July 2014 |url-status=dead |archive-url=https://web.archive.org/web/20141028175114/https://www.iceskating.org.uk/node/6297 |archive-date=28 October 2014}}</ref> The founding committee consisted of several landowners, a vicar, a fellow of [[Trinity College, Cambridge|Trinity College]], a magistrate, two members of parliament, the mayor of [[Cambridge]], the Lord Lieutenant of Cambridge, journalist James Drake Digby, the president of [[Cambridge University]] Skating Club, and Neville Goodman, a graduate of [[Peterhouse, Cambridge]] (and son of [[Potto Brown]]'s milling partner, Joseph Goodman).<ref name="Bird">DL Bird 1979 ''Our Skating Heritage''. London.</ref> The newly formed Association held their first one-and-a-half-mile British professional championship at Thorney in December 1879.

===Figure skating===
{{Main|Figure skating}}
[[File:Jackson Haines.png|thumb|Jackson Haines|291x291px]]
[[File:NSAPINY9 EXTR.jpg|thumb|left|''[[Central Park]], Winter – The Skating Pond'', 1862 lithograph by [[Currier and Ives]]|200x200px]]
The first instructional book concerning ice skating was published in London in 1772. The book titled ''The Art of Figure Skating'', written by a British artillery lieutenant, Robert Jones, describes basic [[figure skating]] forms such as circles and figure eights. The book was written solely for men, as women did not normally ice skate in the late 18th century.{{cn|date=May 2025}} It was with the publication of this manual that ice skating split into its two main disciplines, speed skating and figure skating.

The founder of modern figure skating as it is known today was [[Jackson Haines]], an American. He was the first skater to incorporate ballet and dance movements into his skating, as opposed to focusing on tracing patterns on the ice. Haines also invented the [[sit spin]] and developed a shorter, curved blade for figure skating that allowed for easier turns. He was also the first to wear blades that were permanently attached to the boot.

The [[International Skating Union]] was founded in 1892 as the first international ice skating organisation in [[Scheveningen]], in the Netherlands. The Union created the first codified set of figure skating rules and governed international competition in speed and figure skating. The first Championship, known as the Championship of the Internationale Eislauf-Vereinigung, was held in [[Saint Petersburg]] in 1896. The event had four competitors and was won by [[Gilbert Fuchs]].<ref>Hines, p.75</ref>
{{clear}}

=={{anchor|Physics}} Physical mechanics of skating==

A skate can glide over ice because there is a layer of ice molecules on the surface that are not as tightly bound as the molecules of the mass of ice beneath. These molecules are in a semiliquid state, providing lubrication. The molecules in this "quasi-fluid" or "water-like" layer are less mobile than liquid water, but are much more mobile than the molecules deeper in the ice. At about {{convert|-250|F|order=flip}} the slippery layer is one molecule thick; as the temperature increases the slippery layer becomes thicker.<ref name=nyt060221/><ref name=SS97/><ref name=PPG121223/><ref name=explorat/><ref name=SN9612/>

It had long been believed that ice is slippery because the pressure of an object in contact with it causes a thin layer to melt. The hypothesis was that the blade of an ice skate, exerting pressure on the ice, melts a thin layer, providing lubrication between the ice and the blade. This explanation, called "[[Pressure melting point|pressure melting]]", originated in the 19th century. (See [[Regelation]].) Pressure melting could not account for skating on ice temperatures lower than −3.5 °C, whereas skaters often skate on lower-temperature ice.<ref name=PT0512/>

In the 20th century, an alternative explanation, called "[[friction]] melting", proposed by Lozowski, Szilder, Le Berre, [[Yves Pomeau|Pomeau]], and others showed that because of the [[viscosity|viscous]] frictional heating, a macroscopic layer of melt ice is in-between the ice and the skate. With this they fully explained the low friction with nothing else but macroscopic physics, whereby the frictional heat generated between skate and ice melts a layer of ice.<ref name=Lozowski/><ref name=Berre/><ref name=Scipost/> This is a self-stabilizing mechanism of skating. If by fluctuation the friction gets high, the layer grows in thickness and lowers the friction, and if it gets low, the layer decreases in thickness and increases the friction. The friction generated in the sheared layer of water between skate and ice grows as ''√V'' with ''V'' the velocity of the skater, such that for low velocities the friction is also low.

Whatever the origin of the water layer, skating is more destructive than simply gliding. A skater leaves a visible trail behind on virgin ice and skating rinks have to be regularly resurfaced to improve the skating conditions. It means that the [[deformation (engineering)|deformation]] caused by the skate is plastic rather than elastic. The skate ploughs through the ice in particular due to the sharp edges. [[J.M.J. van Leeuwen|Van Leeuwen]] proposed that another component has to be added to the friction: the "ploughing friction".<ref name=Scipost/><ref name=EPN/> The calculated frictions are of the same order as the measured frictions in real skating in a rink.<ref name=Koning/> The ploughing friction decreases with the velocity ''V'', since the pressure in the water layer increases with V and lifts the skate ([[aquaplaning]]). As a result the sum of the water-layer friction and the ploughing friction only increases slightly with ''V'', making skating at high speeds (>90 km/h) possible.

==Inherent safety risks==
[[File:Ice Skating (12).jpg|thumb|Adult and child ice skating]]
A person's ability to ice skate depends on the roughness of the ice, the design of the ice skate, and the skill and experience of the skater. While serious injury is rare, a number of [[short track speed skating|short track speed skaters]] have been [[paralysis|paralysed]] after a heavy fall when they collided with the boarding. A fall can be fatal if a [[helmet]] is not worn to protect against severe [[head injury]]. Accidents are rare but there is a risk of injury from collisions, particularly during hockey games or in [[pair skating]].

A significant danger when skating outdoors on a frozen body of water is falling through the ice into the freezing water underneath. Death can result from [[cold shock response|shock]], [[hypothermia]], or [[drowning]]. It is often difficult or impossible for the skater to climb out of the water, due to the weight of their ice skates and thick winter clothing, and the ice repeatedly breaking as they struggle to get back onto the surface. Also, if the skater becomes disoriented under the water, they might not be able to find the hole in the ice through which they have fallen. Although this can prove fatal, it is also possible for the rapid cooling to produce a condition in which a person can be revived up to hours after falling into the water. Experts have warned not to ice skate alone, and also warned parents not to leave children unattended on a frozen body of water.

==Communal activities on ice==
[[File:Ice skating on the Maumee River - DPLA - b8f4ed1d5efee68b00420d4e4b6a782f (cropped).jpg|thumb|right|Ice skaters on the Maumee River in Toledo, Ohio, 1890s]]
A number of recreational and sporting activities take place on ice:

===Ice skating===

* [[Fen skating]] – a traditional form of ice skating in the [[The Fens|Fenland]] of England which involved skating races and matches held in towns and villages all over the Fens
* [[Tour skating]] – recreational and competitive long-distance skating outdoors on open areas of natural ice
* [[Speed skating]] – competitive form of ice skating in which contenders race over fixed distances, short track and long track versions
* [[Barrel jumping]] – a speed skating discipline in which skaters jump over a length of multiple barrels<ref>{{cite web |title=World Barrel Jumping Championships 1958 |url=https://www.britishpathe.com/video/world-barrel-jumping-championships |publisher=[[Pathé News|British Pathé]] |access-date=7 December 2015 |url-status=live |archive-url=https://web.archive.org/web/20160304202211/https://www.britishpathe.com/video/world-barrel-jumping-championships |archive-date=4 March 2016}}</ref>
* [[Figure skating]] – winter sport with multiple disciplines: men's singles, ladies' singles, pair skating, ice dance, and [[synchronized skating]]
* [[Bandy]] – non-contact team sport similar to ice hockey, but using a bandy ball and played on a large ice field
* [[Ice hockey]] – fast-paced contact team sport, using a vulcanized rubber puck, usually played on a special ice hockey rink
* [[Rink bandy]] – a form of bandy that can be played on a standard ice hockey rink
* [[Rinkball]] – non-contact team sport using a bandy ball with combined elements from bandy and ice hockey
* [[Ringette]] – non-contact team sport using a rubber pneumatic ring instead of a ball or puck
* [[Ice cross downhill]] – competitive extreme sport featuring downhill skating on a walled track

===No skating===
The following sports and games are also played on ice, but players are not required to wear ice skates.

* [[Ice cricket]] - a variant of the English game of cricket played in harsh wintry conditions
* [[Spongee]] – an outdoor team sport which is a non-contact variant of ice hockey played on outdoor ice hockey rinks
* [[Broomball]] – a team sport played on ice hockey rinks using sticks with paddles to propel a ball into the opposing team's net
* [[Moscow broomball]] – an outdoor team game played using ice hockey equipment and a ball played at the Russian embassy on frozen outdoor courts flooded with water
* [[Curling]] – a team sport using "rocks" and lanes and a target
* [[Ice stock sport|Ice stock]] – a team sport using lanes and a target
* [[Crokicurl]] – an outdoor team sport using "rocks" on an octagonal playing area with posts and a target

==Gallery==
<gallery widths="160" heights="160" class="center" style="center" mode="nolines">
File:Team L.T.D. Cruising to Victory (16227312684).jpg|[[Ice cross downhill]] (Individual)
File:Kim 2010 Olympic FS.jpg|[[Figure skating]] (Individual, Pairs)
File:Team amber WSSC.jpg|[[Synchronized skating]] (Team)
File:Bandy game 1.jpg|[[Bandy]] (Team)
File:УФХМР 2013.jpg|[[Rink bandy]] (Team)
File:Stephen Weiss.jpg|[[Ice hockey]] (Team)
File:Atlantic Attack Ringette Team.jpg|[[Ringette]] (Team)
File:Langfardsskridskoakning.jpg|[[Tour skating]] (Individual)
File:Fenskaters ronden ton.jpg|[[Fen skating]] (Individual)
File:Paulien van Deutekom (08-12-2007).jpg|[[Speed skating]] (Individual)
File:Saguenay 500m.jpg|[[Short track speed skating]] (Individual, Team Relay)
File:Black Forest Village (NBY 417446).jpg|[[Barrel jumping]] (Individual)
</gallery>

===Videos===
<gallery widths="160" heights="160" class="center" style="center" mode="nolines">
File:Eislaufen 01.ogg|Ice skater on [[Lake Neusiedl]].
File:Skating in Central Park Frank-S.-Armitage-American-Mutoscope-And-Biograph-1900.ogv|''Skating in Central Park'' (1900), one minute silent film by Frank S. Armitage. [[EYE Film Institute Netherlands]].
File:Wereldkampioenschappen schaatsen.ogv|Documentary on the World Championship Skating for Women at [[Helsinki]] in 1971.
</gallery>

==See also==
* [[Fen skating]]
* [[Ice resurfacer]]
* [[Kite ice skating]]
* [[Lidwina]], [[patron saint]] of ice skaters

==References==
{{Reflist|30em|refs=
<ref name=PT0512>{{cite journal |url=http://lptms.u-psud.fr/membres/trizac/Ens/L3FIP/Ice.pdf |title=Why is ice slippery? |first=Robert |last=Rosenberg |journal=[[Physics Today]] |volume=58 |issue=12 |pages=50–54 |date=December 2005 |access-date=15 February 2009 |doi=10.1063/1.2169444 |url-status=live |archive-url=https://web.archive.org/web/20140223210434/http://lptms.u-psud.fr/membres/trizac/Ens/L3FIP/Ice.pdf |archive-date=23 February 2014 |bibcode=2005PhT....58l..50R}}</ref>
<ref name=Scipost>{{cite journal |url=https://scipost.org/SciPostPhys.3.6.042 |title=Skating on slippery ice |first=J.M.J. |last=van Leeuwen |author-link=Hans van Leeuwen (physicist) |journal=SciPost Physics |volume=03 |issue=6 |pages=043 |date=23 December 2017 |doi=10.21468/SciPostPhys.3.6.042 |arxiv=1706.08278 |bibcode=2017ScPP....3...42V |s2cid=54066700 |access-date=25 March 2019 |archive-date=6 May 2019 |archive-url=https://web.archive.org/web/20190506015426/https://scipost.org/SciPostPhys.3.6.042 |url-status=live |doi-access=free }}</ref>
<ref name=EPN>{{cite journal |title=Skating on slippery ice |first1=T.H. |last1=Oosterkamp |first2=T. |last2=Boudewijn |first3=J.M.J. |last3=van Leeuwen |journal=Europhysics News |volume=50 |pages=28–32 |date=12 February 2019 |issue=1 |doi=10.1051/epn/2019104 |bibcode=2019ENews..50a..28O |doi-access=free|hdl=1887/80098 |hdl-access=free }}</ref>
<ref name=Lozowski>{{cite journal |title=Derivation and new analysis of a hydrodynamic model of speed skate ice friction |first1=E.P. |last1=Lozowski |first2=K. |last2=Szilder |journal=International Journal of Offshore and Polar Engineering |volume=23 |pages=104 |date=June 2013}}</ref>
<ref name=Berre>{{cite journal |title=Theory of ice-skating |first1=M. |last1=Le Berre |first2=Y. |last2=Pomeau |journal=International Journal of Non-Linear Mechanics |volume=75 |pages=77–86 |date=October 2015 |doi=10.1016/j.ijnonlinmec.2015.02.004|arxiv=1502.00323 |bibcode=2015IJNLM..75...77L |s2cid=119278597 }}</ref>
<ref name=Koning>{{cite journal |title=Ice friction during speed skating. |first1=J.J. |last1=de Koning |first2=G. |last2=de Groot |first3=G.J. |last3=van Ingen Schenau |journal=Journal of Biomechanics |volume=25 |issue=6 |pages=565–571 |date=June 1992 |doi=10.1016/0021-9290(92)90099-m |pmid=1517252}}</ref>
<ref name=pdo130220>{{cite news |url=http://en.people.cn/102774/8135494.html |title='Imperial' ice skating|work=People's Daily Online |date=20 February 2013 |url-status=live |archive-url=https://web.archive.org/web/20160317003728/http://en.people.cn/102774/8135494.html |archive-date=17 March 2016}}</ref>
<ref name=nyt060221>{{cite news |url=https://www.nytimes.com/2006/02/21/science/21ice.html |title=Explaining Ice: The Answers Are Slippery |first=Kenneth |last=Chang |newspaper=[[The New York Times]] |date=21 February 2006 |url-status=live |archive-url=https://web.archive.org/web/20081211055112/https://www.nytimes.com/2006/02/21/science/21ice.html?pagewanted=all |archive-date=11 December 2008}}</ref>
<ref name=SS97>{{cite journal |title=Molecular surface structure of ice(0001): dynamical low-energy electron diffraction, total-energy calculations and molecular dynamics simulations |journal=Surface Science |volume=381 |issue=2–3 |pages=190–210 |date=10 June 1997 |first=G.A. |last=Somorjai |quote=Most studies so far were performed at temperatures well above 240 K (−33 °C) and report the presence of a liquid or quasiliquid layer on ice. Those studies that went below this temperature do not suggest a liquid-like layer. |doi=10.1016/S0039-6028(97)00090-3 |bibcode=1997SurSc.381..190M}}</ref>
<ref name=PPG121223>{{cite news |url=https://www.post-gazette.com/local/city/2012/12/23/Pitt-physics-professor-explains-the-science-of-skating-across-the-ice/stories/201212230227 |title=Pitt physics professor explains the science of skating across the ice |first=Mark |last=Roth |work=[[Pittsburgh Post-Gazette]] |date=23 December 2012 |quote=It used to be thought ... that the reason skaters can glide gracefully across the ice is because the pressure they exert on the sharp blades creates a thin layer of liquid on top of the ice... More recent research has shown, though, that this property isn't why skaters can slide on the ice... It turns out that at the very surface of the ice, water molecules exist in a state somewhere between a pure liquid and a pure solid. ''It's not exactly water – but it's like water. The atoms in this layer are 100,000 times more mobile than the atoms [deeper] in the ice, but they're still 25 times less mobile than atoms in water. So it's like proto-water, and that's what we're really skimming on.'' |access-date=15 July 2021 |archive-date=15 July 2021 |archive-url=https://web.archive.org/web/20210715060239/https://www.post-gazette.com/local/city/2012/12/23/Pitt-physics-professor-explains-the-science-of-skating-across-the-ice/stories/201212230227 |url-status=live }}</ref>
<ref name=explorat>{{cite web |url=https://www.exploratorium.edu/hockey/ice2.html |title=Slippery All the Time |publisher=[[Exploratorium]] |quote=Professor Somorjai's findings indicate that ice itself is slippery. You don't need to melt the ice to skate on it, or need a layer of water as a lubricant to help slide along the ice... the "quasi-fluid" or "water-like" layer exists on the surface of the ice and may be thicker or thinner depending on temperature. At about 250 degrees below zero Fahrenheit (−157 °C), the ice has a slippery layer one molecule thick. As the ice is warmed, the number of these slippery layers increases. |url-status=live |archive-url=https://web.archive.org/web/20120719170256/https://www.exploratorium.edu/hockey/ice2.html |archive-date=19 July 2012}}</ref>
<ref name=SN9612>{{cite news |url=https://www.science.org/content/article/getting-grip-ice |title=Getting a Grip on Ice |author=Science News Staff |website=Science NOW |date=9 December 1996 |access-date=30 June 2022 |archive-date=2 December 2022 |archive-url=https://web.archive.org/web/20221202140418/https://www.science.org/content/article/getting-grip-ice |url-status=live }}</ref>
}}

==External links==
{{Commons category|Ice skating}}
{{Wiktionary|ice skating}}
{{Wikivoyage}}
*[https://web.archive.org/web/20190629193459/https://www.skridsko.net/klubbar/data/science.html Skating and Science] (a bibliography)
*{{cite EB1911|wstitle=Skating|short=x}}

{{Winter Olympic sports}}
{{Authority control}}

[[Category:Ice skating| ]]
[[Category:Skating]]
[[Category:Ice skating sports| ]]
[[Category:Winter Olympic sports]]
[[Category:Articles containing video clips]]

Goal line (gridiron football)

2025-05-22T15:52:57Z

45.232.105.68:

{{Short description|Line in American football and Canadian football}}
[[File:Steelers Chiefs goal line.jpg|thumb|The [[Kansas City Chiefs]] (red) and the [[Pittsburgh Steelers]] (black) line up for a play on the goal line.]]
The '''goal line''' is the chalked or painted line dividing the [[end zone]] from the field of play in [[gridiron football]]. In [[American football]] the goal lines run {{convert|10|yd|m}} parallel to the end lines, while in [[Canadian football]] they run {{convert|20|yd|m}} parallel to the dead lines. In both football codes the distance is measured from the inside edge of the end line to the far edge of the goal line so that the line itself is part of the end zone. It is the line that must be crossed in order to score a [[touchdown]].<ref>{{cite book|url=https://archive.org/details/footballmadesimp00dave|url-access=registration|page=[https://archive.org/details/footballmadesimp00dave/page/5 5]|title=Football Made Simple: A Spectator's Guide|first1=Dave|last1=Ominsky|first2=P. J.|last2=Harari|date=1 September 2002|publisher=First Base Sports, Inc.|isbn=9781884309120 |via=Internet Archive}}</ref>

If any part of the ball reaches any part of the imaginary vertical plane transected by this line while [[out-of-bounds|in-bounds]] and in possession of a player whose team is striving toward that end of the field, this is considered a touchdown and scores six points for the team whose player has advanced the ball to, or recovered the ball in, this position. This is in contrast with other sports like [[Association football]] and [[ice hockey]], which require the puck or ball to pass completely over the goal line to count as a score.

If any member of the [[offensive team]] is [[down (football)|downed]] while in possession of the ball behind his own team's goal line, this is called a [[Safety (American football score)|safety]] and scores two points for the [[defensive team]].

If, during the course of play, a loose ball travels past the goal line and is recovered within the [[end zone]], then it is a touchdown if recovered by the team that scores in that end zone, or a [[touchback]] if recovered and downed by the opposing team

In the event of a kick recovered in one's own end zone, the entirety of the ball must pass the goal line in order for the ball to be considered a touchback, and to not be in the field of play.

== References ==
{{reflist}}
== See also ==
* [[Glossary of American football terms]]

{{American football concepts}}

{{DEFAULTSORT:Goal Line (American Football)}}
[[Category:American football terminology]]
[[Category:Canadian football terminology]]

{{Americanfootball-stub}}