Editing Ernest Rutherford (section)

=== Work with radioactivity ===
Again under Thomson's leadership, Rutherford worked on the conductive effects of X-rays on gases, which led to the discovery of the [[electron]], the results first presented by Thomson in 1897.<ref name=Hindu/><ref>{{cite book |last1=Buchwald |first1=Jed Z. |last2=Warwick |first2=Andrew |title=Histories of the electron: the birth of microphysics |date=30 January 2004 |publisher=MIT Press |location=Cambridge, Mass. |isbn=0262524244 |pages=21–30 |url=https://books.google.com/books?id=1yqqhlIdCOoC&pg=PA21 |access-date=27 June 2023 |archive-date=29 August 2023 |archive-url=https://web.archive.org/web/20230829163251/https://books.google.com/books?id=1yqqhlIdCOoC&pg=PA21 |url-status=live }}</ref> Hearing of [[Henri Becquerel]]'s experience with [[uranium]], Rutherford started to explore its [[radioactivity]], discovering two types that differed from X-rays in their penetrating power. Continuing his research in Canada, in 1899 he coined the terms "[[alpha ray]]" and "[[beta ray]]" to describe these two distinct types of [[radioactivity|radiation]].<ref name=abg>{{Cite journal|last=Trenn|first=Thaddeus J.|date=1976|title=Rutherford on the Alpha-Beta-Gamma Classification of Radioactive Rays|journal=Isis|volume=67|issue=1|pages=61–75|jstor=231134|doi=10.1086/351545|s2cid=145281124}}</ref>

In 1898, Rutherford was accepted to the [[William Christopher Macdonald|chair of Macdonald Professor of physics]] position at [[McGill University]] in Montreal, Canada, on Thomson's recommendation.<ref>{{cite book| first=Robin| last=McKown| authorlink=Robin McKown|title=Giant of the Atom, Ernest Rutherford| url=https://archive.org/details/giantofatomernes00mcko|url-access=registration|year=1962|publisher=Julian Messner Inc, New York|page=[https://archive.org/details/giantofatomernes00mcko/page/57 57]}}</ref> From 1900 to 1903, he was joined at McGill by the young chemist [[Frederick Soddy]] ([[Nobel Prize in Chemistry]], 1921) for whom he set the problem of identifying the [[noble gas]] emitted by the radioactive element [[thorium]], a substance which was itself radioactive and would coat other substances. Once he had eliminated all the normal chemical reactions, Soddy suggested that it must be one of the inert gases, which they named [[thoron]]. This substance was later found to be [[Isotopes of radon|<sup>220</sup>Rn]], an isotope of radon.<ref name="Kragh">{{Cite arXiv|last=Kragh|first=Helge|date=5 February 2012|title=Rutherford, Radioactivity, and the Atomic Nucleus|eprint=1202.0954|class=physics.hist-ph}}</ref><ref name="Nobel Rutherford Biography"/> They also found another substance they called Thorium X, later identified as [[Radium#Isotopes|<sup>224</sup>Rn]], and continued to find traces of helium. They also worked with samples of "Uranium X" ([[protactinium]]), from [[William Crookes]], and [[radium]], from [[Marie Curie]]. Rutherford further investigated thoron in conjunction with [[Robert Bowie Owens|R.B. Owens]] and found that a sample of radioactive material of any size invariably took the same amount of time for half the sample to decay (in this case, 11{{frac|1|2}} minutes), a phenomenon for which he coined the term "[[half-life]]".<ref name="Kragh"/> Rutherford and Soddy published their paper "Law of Radioactive Change" to account for all their experiments. Until then, atoms were assumed to be the indestructible basis of all matter; and although Curie had suggested that radioactivity was an atomic phenomenon, the idea of the atoms of radioactive substances breaking up was a radically new idea. Rutherford and Soddy demonstrated that radioactivity involved the spontaneous disintegration of atoms into other, as yet, unidentified matter.<ref name="Nobel Rutherford Biography"/>

In 1903, Rutherford considered a type of radiation, discovered (but not named) by French chemist [[Paul Villard]] in 1900, as an emission from [[radium]], and realised that this observation must represent something different from his own alpha and beta rays, due to its very much greater penetrating power. Rutherford therefore gave this third type of radiation the name of [[gamma ray]].<ref name=abg/> All three of Rutherford's terms are in standard use today – other types of [[radioactive decay]] have since been discovered, but Rutherford's three types are among the most common. In 1904, Rutherford suggested that radioactivity provides a source of energy sufficient to explain the existence of the Sun for the many millions of years required for the slow biological evolution on Earth proposed by biologists such as [[Charles Darwin]]. The physicist [[William Thomson, 1st Baron Kelvin#Age of Earth|Lord Kelvin had argued]] earlier for a much younger Earth, based on the insufficiency of known energy sources, but Rutherford pointed out, at a lecture attended by Kelvin, that radioactivity could solve this problem.<ref name="England et al 2007">{{cite journal |author1=England, P. |author2=Molnar, P. |author3=Righter, F. | title=John Perry's neglected critique of Kelvin's age for the Earth: A missed opportunity in geodynamics |journal=GSA Today |date=January 2007 |volume=17 |issue=1 |pages=4–9 |doi=10.1130/GSAT01701A.1 |bibcode=2007GSAT...17R...4E |doi-access= free}}</ref> Later that year, he was elected as a member to the [[American Philosophical Society]],<ref>{{Cite web|title=APS Member History|url=https://search.amphilsoc.org/memhist/search?creator=&title=&subject=&subdiv=&mem=&year=1904&year-max=&dead=&keyword=&smode=advanced|access-date=28 June 2021|website=search.amphilsoc.org|archive-date=28 June 2021|archive-url=https://web.archive.org/web/20210628190035/https://search.amphilsoc.org/memhist/search?creator=&title=&subject=&subdiv=&mem=&year=1904&year-max=&dead=&keyword=&smode=advanced|url-status=live}}</ref> and in 1907 he returned to Britain to take the [[Chair (academic department)|chair]] of physics at the [[Victoria University of Manchester]].<ref>{{cite web |title=Ernest Rutherford: Heritage Heroes at The University of Manchester |url=https://www.manchester.ac.uk/discover/history-heritage/history/heroes/ernest-rutherford/ |website=The University of Manchester |access-date=27 June 2023 |language=en |archive-date=27 June 2023 |archive-url=https://web.archive.org/web/20230627004723/https://www.manchester.ac.uk/discover/history-heritage/history/heroes/ernest-rutherford/ |url-status=live }}</ref>

In Manchester, Rutherford continued his work with alpha radiation. In conjunction with [[Hans Geiger]], he developed zinc sulfide [[Scintillation (physics)|scintillation]] screens and [[ionisation chamber]]s to count alpha particles. By dividing the total charge accumulated on the screen by the number counted, Rutherford determined that the charge on the alpha particle was two.<ref>{{Cite journal |date=1908-08-27 |title=The charge and nature of the α-particle |journal=Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character |language=en |volume=81 |issue=546 |pages=162–173 |doi=10.1098/rspa.1908.0066 |bibcode=1908RSPSA..81..162R |issn=0950-1207 |last1=Rutherford |first1=E. |last2=Geiger |first2=Hans |doi-access=free }}</ref><ref name=PaisInwardBound>{{Cite book |last=Pais |first=Abraham |title=Inward bound: of matter and forces in the physical world |date=2002 |publisher=Clarendon Press [u.a.] |isbn=978-0-19-851997-3 |edition=Reprint |location=Oxford}}</ref>{{rp|61}} In late 1907, Ernest Rutherford and [[Thomas Royds]] allowed alphas to penetrate a very thin window into an evacuated tube. As they [[atomic emission spectroscopy|sparked the tube into discharge]], the spectrum obtained from it changed, as the alphas accumulated in the tube. Eventually, the clear spectrum of helium gas appeared, proving that alphas were at least ionised helium atoms, and probably helium nuclei.<ref>{{cite journal |last1=Rutherford |first1=E. |last2=Royds |first2=T. |title=XXI. The nature of the α particle from radioactive substances |journal=The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science |date=February 1909 |volume=17 |issue=98 |pages=281–286 |doi=10.1080/14786440208636599 |url=https://zenodo.org/record/1430648 |access-date=11 August 2023 |archive-date=7 May 2021 |archive-url=https://web.archive.org/web/20210507040356/https://zenodo.org/record/1430648 |url-status=live }}</ref> 
In 1910 Rutherford, with Geiger and mathematician [[Harry Bateman]] published<ref>{{cite journal |last1=Rutherford |first1=E. |last2=Geiger |first2=H. |last3=Bateman |first3=H. |title=LXXVI. The probability variations in the distribution of α particles |journal=The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science |date=October 1910 |volume=20 |issue=118 |pages=698–707 |doi=10.1080/14786441008636955 |url=https://zenodo.org/record/1430880 |access-date=11 August 2023 |archive-date=29 August 2023 |archive-url=https://web.archive.org/web/20230829170123/https://zenodo.org/record/1430880 |url-status=live }}</ref>
their classic paper<ref>Bulmer, M. G. (1979). Principles of Statistics. United Kingdom: Dover Publications.</ref>{{rp|94}} describing the first analysis of the distribution in time of radioactive emission, a distribution now called the [[Poisson distribution]].

Ernest Rutherford was awarded the [[List of Nobel laureates in Chemistry|1908 Nobel Prize in Chemistry]] "for his investigations into the disintegration of the elements, and the chemistry of radioactive substances".<ref>{{cite web |title=The Nobel Prize in Chemistry 1908 |url=https://www.nobelprize.org/prizes/chemistry/1908/summary/ |website=The Nobel Prize |publisher=The Nobel Foundation |access-date=2 April 2020 |archive-date=8 July 2018 |archive-url=https://web.archive.org/web/20180708045209/https://www.nobelprize.org/nobel_prizes/chemistry/laureates/1908/index.html |url-status=live }}</ref><ref name="Nobel Rutherford Biography" />