Editing Kinetic theory of gases (section)

== History ==
{{See also|Heat#History|Atomism|History of thermodynamics}}

=== Kinetic theory of matter ===

==== Antiquity ====
In about 50 [[before common era|BCE]], the Roman philosopher [[Lucretius]] proposed that apparently static macroscopic bodies were composed on a small scale of rapidly moving atoms all bouncing off each other.<ref>{{Cite journal|last1=Maxwell|first1=J. C.|year=1867|title=On the Dynamical Theory of Gases|journal=Philosophical Transactions of the Royal Society of London|volume=157|pages=49–88|doi=10.1098/rstl.1867.0004|s2cid=96568430}}</ref> This [[Epicureanism|Epicurean]] atomistic point of view was rarely considered in the subsequent centuries, when [[Aristotle]]an ideas were dominant.{{citation needed|date=December 2024}}

==== Modern era ====

===== "Heat is motion" =====
[[File:Portrait of Francis Bacon (cropped).jpg|thumb|196x196px|Francis Bacon]]
One of the first and boldest statements on the relationship between motion of particles and [[heat]] was by the English philosopher [[Francis Bacon]] in 1620. "It must not be thought that heat generates motion, or motion heat (though in some respects this be true), but that the very essence of heat ... is motion and nothing else."<ref>{{Cite book |last=Bacon |first=F. |author-link=Francis Bacon |url=https://www.gutenberg.org/cache/epub/45988/pg45988-images.html |title=Novum Organum: Or True Suggestions for the Interpretation of Nature |publisher=P. F. Collier & son |year=1902 |editor-last=Dewey |editor-first=J. |pages=153 |orig-date=1620}}</ref> "not a ... motion of the whole, but of the small particles of the body."<ref>{{Cite book |last=Bacon |first=F. |author-link=Francis Bacon |url=https://www.gutenberg.org/cache/epub/45988/pg45988-images.html |title=Novum Organum: Or True Suggestions for the Interpretation of Nature |publisher=P. F. Collier & son |year=1902 |editor-last=Dewey |editor-first=J. |pages=156 |orig-date=1620}}</ref> In 1623, in ''[[The Assayer]]'', [[Galileo Galilei]], in turn, argued that heat, pressure, smell and other phenomena perceived by our senses are apparent properties only, caused by the movement of particles, which is a real phenomenon.{{Sfn|Galilei|1957|p=273-4}}<ref>{{Citation |last=Adriaans |first=Pieter |title=Information |date=2024 |encyclopedia=The Stanford Encyclopedia of Philosophy |page=3.4 Physics |editor-last=Zalta |editor-first=Edward N. |url=https://plato.stanford.edu/archives/sum2024/entries/information/#Phys |edition=Summer 2024 |publisher=Metaphysics Research Lab, Stanford University |editor2-last=Nodelman |editor2-first=Uri}}</ref>
[[File:John_Locke._Portrait_by_Herman_Verelst_(cropped).jpg|thumb|184x184px|John Locke]]
In 1665, in ''[[Micrographia]]'', the English polymath [[Robert Hooke]] repeated Bacon's assertion,<ref>{{Cite book |last=Hooke |first=Robert |url=https://ttp.royalsociety.org/ttp/ttp.html?id=a9c4863d-db77-42d1-b294-fe66c85958b3&type=book |title=Micrographia: Or Some Physiological Descriptions of Minute Bodies Made by Magnifying Glasses with Observations and Inquiries Thereupon |publisher=Printed by Jo. Martyn, and Ja. Allestry, Printers to the Royal Society |year=1665 |pages=12 |postscript=. (Facsimile, with pagination)}}</ref><ref>{{Cite book |last=Hooke |first=Robert |url=https://www.gutenberg.org/files/15491/15491-h/15491-h.htm |title=Micrographia: Or Some Physiological Descriptions of Minute Bodies Made by Magnifying Glasses with Observations and Inquiries Thereupon |publisher=Printed by Jo. Martyn, and Ja. Allestry, Printers to the Royal Society |year=1665 |pages=12 |postscript=. (Machine-readable, no pagination)}}</ref> and in 1675, his colleague, Anglo-Irish scientist [[Robert Boyle]] noted that a hammer's "impulse" is transformed into the motion of a nail's constituent particles, and that this type of motion is what heat consists of.<ref>{{Cite book |last=Boyle |first=Robert |url=https://archive.org/details/experimentsnotes00boyl/page/n100/mode/1up |title=Experiments, notes, &c., about the mechanical origine or production of divers particular qualities: Among which is inserted a discourse of the imperfection of the chymist's doctrine of qualities; together with some reflections upon the hypothesis of alcali and acidum |publisher=Printed by E. Flesher, for R. Davis |year=1675 |pages=61–62}}</ref> Boyle also believed that all macroscopic properties, including color, taste and elasticity, are caused by and ultimately consist of nothing but the arrangement and motion of indivisible particles of matter.<ref>{{Citation |last=Chalmers |first=Alan |title=Atomism from the 17th to the 20th Century |date=2019 |encyclopedia=The Stanford Encyclopedia of Philosophy |page=2.1 Atomism and the Mechanical Philosophy |editor-last=Zalta |editor-first=Edward N. |url=https://plato.stanford.edu/entries/atomism-modern/#AtoMec |edition=Spring 2019 |publisher=Metaphysics Research Lab, Stanford University}}</ref> In a lecture of 1681, Hooke asserted a direct relationship between the temperature of an object and the speed of its internal particles. "Heat ... is nothing but the internal Motion of the Particles of [a] Body; and the hotter a Body is, the more violently are the Particles moved."<ref>{{Cite book |last=Hooke |first=Robert |url=https://archive.org/details/b30454621_0001/page/116/mode/1up |title=The posthumous works of Robert Hooke ... containing his Cutlerian lectures, and other discourses, read at the meetings of the illustrious Royal Society ... Illustrated with sculptures. To these discourses is prefixt the author's life, giving an account of his studies and employments, with an enumeration of the many experiments, instruments, contrivances and inventions, by him made and produc'd as Curator of Experiments to the Royal Society |publisher=Publish'd by Richard Waller. Printed by Sam. Smith and Benj. Walford, (Printers to the Royal Society) |year=1705 |pages=116 |language=en |orig-date=1681}}</ref> In a manuscript published 1720, the English philosopher [[John Locke]] made a very similar statement: "What in our sensation is ''heat'', in the object is nothing but ''motion''."<ref>{{Cite book |last=Locke |first=John |url=https://archive.org/details/acollectionseve01desmgoog/page/n291/mode/1up |title=A collection of several pieces of Mr. John Locke, never before printed, or not extant in his works. |publisher=Printed by J. Bettenham for R. Francklin |year=1720 |pages=224 |via=Internet Archive}}</ref><ref>{{Cite book |last=Locke |first=John |url=https://play.google.com/books/reader?id=QqxsP-VKrpkC&pg=GBS.PA224 |title=A collection of several pieces of Mr. John Locke, never before printed, or not extant in his works. |publisher=Printed by J. Bettenham for R. Francklin |year=1720 |pages=224 |via=Google Play Books}}</ref> Locke too talked about the motion of the internal particles of the object, which he referred to as its "insensible parts".[[File:Catherine II visiting Mikhail Lomonosov by Ivan Feodorov 1884.jpg|thumb|[[Catherine the Great]] visiting Mikhail Lomonosov]]
In his 1744 paper ''Meditations on the Cause of Heat and Cold'', Russian polymath [[Mikhail Lomonosov]] made a relatable appeal to everyday experience to gain acceptance of the microscopic and kinetic nature of matter and heat:<ref>{{Cite book |last=Lomonosov |first=Mikhail Vasil'evich |url=https://archive.org/details/mikhailvasilevic017733mbp |title=Mikhail Vasil'evich Lomonosov on the Corpuscular Theory |publisher=Harvard University Press |year=1970 |editor-last=Leicester |editor-first=Henry M. |pages=100 |translator-last= |translator-first= |chapter=Meditations on the Cause of Heat and Cold |orig-date=1750 |chapter-url=https://archive.org/details/mikhailvasilevic017733mbp/page/n115/mode/1up}}</ref>{{Blockquote|text=Movement should not be denied based on the fact it is not seen. Who would deny that the leaves of trees move when rustled by a wind, despite it being unobservable from large distances? Just as in this case motion remains hidden due to perspective, it remains hidden in warm bodies due to the extremely small sizes of the moving particles. In both cases, the viewing angle is so small that neither the object nor their movement can be seen.}}Lomonosov also insisted that movement of particles is necessary for the processes of [[Solvation|dissolution]], [[Extraction (chemistry)|extraction]] and [[diffusion]], providing as examples the dissolution and diffusion of salts by the action of water particles on the of the “molecules of salt”, the dissolution of metals in mercury, and the extraction of plant pigments by alcohol.<ref>{{Cite book |last=Lomonosov |first=Mikhail Vasil'evich |url=https://archive.org/details/mikhailvasilevic017733mbp |title=Mikhail Vasil'evich Lomonosov on the Corpuscular Theory |publisher=Harvard University Press |year=1970 |editor-last=Leicester |editor-first=Henry M. |pages=102–3 |translator-last= |translator-first= |chapter=Meditations on the Cause of Heat and Cold |orig-date=1750 |chapter-url=https://archive.org/details/mikhailvasilevic017733mbp/page/n115/mode/1up}}</ref>

Also the [[Heat transfer|transfer of heat]] was explained by the motion of particles. Around 1760, Scottish physicist and chemist [[Joseph Black]] wrote: "Many have supposed that heat is a tremulous ... motion of the particles of matter, which ... motion they imagined to be communicated from one body to another."<ref>{{Cite book |last=Black |first=Joseph |author-link=Joseph Black |url=https://books.google.com/books?id=lqI9AQAAMAAJ&pg=PA80 |title=Lectures on the Elements of Chemistry: Delivered in the University of Edinburgh |date=1807 |publisher=Mathew Carey |editor-last=Robinson |editor-first=John |edition= |pages=80 |language=en}}</ref>

=== Kinetic theory of gases ===
[[File:Porträt des Daniel Bernoulli (cropped).jpg|thumb|167x167px|Daniel Bernoulli]]
[[Image:HYDRODYNAMICA, Danielis Bernoulli.png|thumb|upright|''Hydrodynamica'' front cover]]

In 1738 [[Daniel Bernoulli]] published ''[[Hydrodynamica]]'', which laid the basis for the [[Kinetic energy|kinetic]] theory of [[gas]]es. In this work, Bernoulli posited the argument, that gases consist of great numbers of molecules moving in all directions, that their impact on a surface causes the pressure of the gas, and that their average [[kinetic energy]] determines the temperature of the gas. The theory was not immediately accepted, in part because [[conservation of energy]] had not yet been established, and it was not obvious to [[physicist]]s how the collisions between molecules could be perfectly elastic.<ref name="PonomarevKurchatov1993">{{cite book|title=The Quantum Dice|author1=L.I Ponomarev|author2=I.V Kurchatov|date=1 January 1993|publisher=CRC Press|isbn=978-0-7503-0251-7}}</ref>{{rp|36–37}}

Pioneers of the kinetic theory, whose work was also largely neglected by their contemporaries, were Mikhail Lomonosov (1747),<ref>Lomonosov 1758</ref> [[Georges-Louis Le Sage]] (ca. 1780, published 1818),<ref>Le Sage 1780/1818</ref> [[John Herapath]] (1816)<ref>Herapath 1816, 1821</ref> and [[John James Waterston]] (1843),<ref>Waterston 1843</ref> which connected their research with the development of [[mechanical explanations of gravitation]].

In 1856 [[August Krönig]] created a simple gas-kinetic model, which only considered the [[Translation (geometry)|translational motion]] of the particles.<ref>Krönig 1856</ref> In 1857 [[Rudolf Clausius]] developed a similar, but more sophisticated version of the theory, which included translational and, contrary to Krönig, also [[rotation]]al and vibrational molecular motions. In this same work he introduced the concept of [[mean free path]] of a particle.<ref>Clausius 1857</ref> In 1859, after reading a paper about the [[diffusion]] of molecules by Clausius, Scottish physicist [[James Clerk Maxwell]] formulated the [[Maxwell distribution]] of molecular velocities, which gave the proportion of molecules having a certain velocity in a specific range.<ref>See:
* Maxwell, J.C. (1860) [https://books.google.com/books?id=-YU7AQAAMAAJ&pg=PA19 "Illustrations of the dynamical theory of gases. Part I. On the motions and collisions of perfectly elastic spheres,"] ''Philosophical Magazine'', 4th series, '''19''' : 19–32.
* Maxwell, J.C. (1860) [https://books.google.com/books?id=DIc7AQAAMAAJ&pg=PA21 "Illustrations of the dynamical theory of gases. Part II. On the process of diffusion of two or more kinds of moving particles among one another,"] ''Philosophical Magazine'', 4th series, '''20''' : 21–37.</ref> This was the first-ever statistical law in physics.<ref>{{cite book|title=The Man Who Changed Everything – the Life of James Clerk Maxwell|author=Mahon, Basil|publisher=Wiley|year=2003|isbn=0-470-86171-1|location=Hoboken, NJ|oclc=52358254}}</ref> Maxwell also gave the first mechanical argument that molecular collisions entail an equalization of temperatures and hence a tendency towards equilibrium.<ref>{{Cite journal|last1=Gyenis|first1=Balazs|year=2017|title=Maxwell and the normal distribution: A colored story of probability, independence, and tendency towards equilibrium|journal=Studies in History and Philosophy of Modern Physics|volume=57|pages=53–65|arxiv=1702.01411|bibcode=2017SHPMP..57...53G|doi=10.1016/j.shpsb.2017.01.001|s2cid=38272381}}</ref> In his 1873 thirteen page article 'Molecules', Maxwell states: "we are told that an 'atom' is a material point, invested and surrounded by 'potential forces' and that when 'flying molecules' strike against a solid body in constant succession it causes what is called [[pressure]] of air and other gases."<ref>Maxwell 1873</ref>
In 1871, [[Ludwig Boltzmann]] generalized Maxwell's achievement and formulated the [[Maxwell–Boltzmann distribution]]. The [[logarithm]]ic connection between [[entropy]] and [[probability]] was also first stated by Boltzmann.

At the beginning of the 20th century, atoms were considered by many physicists to be purely hypothetical constructs, rather than real objects. An important turning point was [[Albert Einstein]]'s (1905)<ref>Einstein 1905</ref> and [[Marian Smoluchowski]]'s (1906)<ref>Smoluchowski 1906</ref> papers on [[Brownian motion]], which succeeded in making certain accurate quantitative predictions based on the kinetic theory.

Following the development of the [[Boltzmann equation]], a framework for its use in developing transport equations was developed independently by [[David Enskog]] and [[Sydney Chapman (mathematician)|Sydney Chapman]] in 1917 and 1916. The framework provided a route to prediction of the transport properties of dilute gases, and became known as [[Chapman–Enskog theory]]. The framework was gradually expanded throughout the following century, eventually becoming a route to prediction of transport properties in real, dense gases.