Editing Ernest Rutherford (section)

== Scientific career ==
[[File:Ernest Rutherford 1892.jpg|thumb|right|Rutherford in 1892, aged 21]]

When Rutherford began his studies at Cambridge, he was among the first 'aliens' (those without a Cambridge degree) allowed to do research at the university, and was additionally honoured to study under [[J. J. Thomson]].<ref name="aps" />

With Thomson's encouragement, Rutherford detected radio waves at {{convert|0.5|mi|m}}, and briefly held the world record for the distance over which electromagnetic waves could be detected, although when he presented his results at the [[British Association]] meeting in 1896, he discovered he had been outdone by [[Guglielmo Marconi]], whose radio waves had sent a message across nearly {{convert|10|mi|km}}.<ref>{{cite news |last1=Holmes |first1=Jonathan |title=Marconi's first radio broadcast made 125 years ago |url=https://www.bbc.com/news/uk-england-somerset-61327062 |access-date=16 June 2023 |work=BBC News |date=13 May 2022 |archive-date=5 June 2023 |archive-url=https://web.archive.org/web/20230605224315/https://www.bbc.com/news/uk-england-somerset-61327062 |url-status=live }}</ref>

=== 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" />

=== Model of the atom ===
{{See also|Rutherford–Bohr model| Rutherford scattering}}
[[File:Gold foil experiment conclusions.svg|right|thumb|''Top:'' Expected results: [[alpha particle]]s passing through the [[plum pudding model]] of the atom undisturbed.<br />
''Bottom:'' Observed results: a small portion of the particles were deflected, indicating [[Atomic nucleus|a small, concentrated charge]]. Diagram is not to scale; in reality the nucleus is vastly smaller than the electron shell.]]

Rutherford continued to make ground-breaking discoveries long after receiving the Nobel prize in 1908.<ref name=PaisInwardBound/>{{rp|63|q=...Rutherford, who rose to his greatest heights after 1908, most notably because of his discovery of the atomic nucleus}} Under his direction in 1909, [[Hans Geiger]] and [[Ernest Marsden]] performed the [[Geiger–Marsden experiment]], which demonstrated the nuclear nature of atoms by measuring the deflection of [[alpha particles]] passing through a thin gold foil.<ref>{{cite web |last1=Pestka |first1=Jessica |title=About Rutherford's Gold Foil Experiment |url=https://sciencing.com/rutherfords-gold-foil-experiment-4569065.html |website=Sciencing |access-date=27 June 2023 |language=en |date=25 April 2017 |archive-date=27 June 2023 |archive-url=https://web.archive.org/web/20230627004502/https://sciencing.com/rutherfords-gold-foil-experiment-4569065.html |url-status=live }}</ref> Rutherford was inspired to ask Geiger and Marsden in this experiment to look for alpha particles with very high deflection angles, which was not expected according to any theory of matter at that time.<ref>{{cite book |last1=Dragovich |first1=Branko |title=Ernest Rutherford and the Discovery of the Atomic Nucleus |publisher=Institute of Physics |location=Belgrade |url=http://bsw2011.seenet-mtp.info/pub/bss2011-DragovichB-abs.pdf |access-date=27 June 2023 |archive-date=27 June 2023 |archive-url=https://web.archive.org/web/20230627004502/http://bsw2011.seenet-mtp.info/pub/bss2011-DragovichB-abs.pdf |url-status=live }}</ref><ref>{{cite journal |last1=Davidson |first1=Michael W. |title=Pioneers in Optics: Johann Wilhelm Ritter and Ernest Rutherford |journal=Microscopy Today |date=March 2014 |volume=22 |issue=2 |pages=48–51 |doi=10.1017/S1551929514000029 |url=https://www.cambridge.org/core/services/aop-cambridge-core/content/view/E8B7456A024C6ED07D4E891F540C8EE2/S1551929514000029a.pdf/pioneers-in-optics-johann-wilhelm-ritter-and-ernest-rutherford.pdf |access-date=27 June 2023 |publisher=Cambridge University Press |s2cid=135584871 |archive-date=3 January 2023 |archive-url=https://web.archive.org/web/20230103220843/https://www.cambridge.org/core/services/aop-cambridge-core/content/view/E8B7456A024C6ED07D4E891F540C8EE2/S1551929514000029a.pdf/pioneers-in-optics-johann-wilhelm-ritter-and-ernest-rutherford.pdf |url-status=live }}</ref> Such deflection angles, although rare, were found. Reflecting on these results in one of his last lectures, Rutherford was quoted as saying: "It was quite the most incredible event that has ever happened to me in my life. It was almost as incredible as if you fired a 15-inch shell at a piece of tissue paper and it came back and hit you."<ref>''The Development of the Theory of Atomic Structure'' (Rutherford 1936). Reprinted in [https://archive.org/details/backgroundtomode032734mbp/page/n85/mode/2up ''Background to Modern Science: Ten Lectures at Cambridge arranged by the History of Science Committee 1936'']</ref> It was Rutherford's interpretation of this data that led him to propose the [[Atomic nucleus|nucleus]], a very small, [[charge (physics)|charged]] region containing much of the atom's mass.<ref name=charge>{{Cite journal |last1=Rutherford |first1=E. |year=1911 |title=The scattering of α and β particles by matter and the structure of the atom |url=http://www.math.ubc.ca/~cass/rutherford/rutherford688.html |journal=The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science |series=Series 6 |volume=21 |issue=125 |pages=669–688 |doi=10.1080/14786440508637080 |access-date=6 October 2012 |archive-date=7 June 2012 |archive-url=https://web.archive.org/web/20120607013629/http://www.math.ubc.ca/~cass/rutherford/rutherford688.html |url-status=live }}</ref>

In 1912, Rutherford was joined by [[Niels Bohr]] (who postulated that electrons moved in specific orbits about the compact nucleus). Bohr adapted Rutherford's nuclear structure to be consistent with [[Max Planck]]'s quantum hypothesis. The resulting [[Rutherford–Bohr model]] was the basis for [[quantum mechanics|quantum mechanical]] atomic physics of Heisenberg which remains valid today.<ref name="Nobel Rutherford Biography"/>

=== Piezoelectricity ===
During World War I, Rutherford worked on a top-secret project to solve the practical problems of submarine detection. Both Rutherford and [[Paul Langevin]] suggested the use of [[piezoelectricity]], and Rutherford successfully developed a device which measured its output. The use of piezoelectricity then became essential to the development of [[ultrasound]] as it is known today. The claim that Rutherford developed [[sonar]], however, is a misconception, as subaquatic detection technologies utilise Langevin's [[Piezoelectric sensor|transducer]].<ref>{{cite journal |last1=Katzir |first1=Shaul |title=Who knew piezoelectricity? Rutherford and Langevin on submarine detection and the invention of sonar |journal=Notes and Records of the Royal Society |date=20 June 2012 |volume=66 |issue=2 |pages=141–157 |doi=10.1098/rsnr.2011.0049 |s2cid=1240938 |url=https://royalsocietypublishing.org/doi/epdf/10.1098/rsnr.2011.0049 |access-date=2 July 2023}}</ref><ref>{{cite journal |last1=Duck |first1=Francis |title=Paul Langevin, U-boats, and ultrasonics |journal=Physics Today |date=1 November 2022 |volume=75 |issue=11 |pages=42–48 |doi=10.1063/PT.3.5122 |bibcode=2022PhT....75k..42D |s2cid=253280842 |doi-access=free }}</ref>

=== Discovery of the proton ===
Together with [[Henry Moseley|H.G. Moseley]], Rutherford developed the [[atomic number|atomic numbering system]] in 1913. Rutherford and Moseley's experiments used [[cathode rays]] to bombard various elements with streams of electrons and observed that each element responded in a consistent and distinct manner. Their research was the first to assert that each element could be defined by the properties of its inner structures – an observation that later led to the discovery of the [[atomic nucleus]].<ref name="Nobel Rutherford Biography"/> This research led Rutherford to theorize that the hydrogen atom (at the time the least massive entity known to bear a positive charge) was a sort of "positive electron" – a component of every atomic element.<ref>{{cite journal |last1=Rutherford |first1=Ernest |title=The structure of the atom |journal=Philosophical Magazine |date=1914 |volume=27 |pages=488–498 |url=http://www.ub.edu/hcub/hfq/sites/default/files/ruth1914%285%29.pdf |access-date=13 June 2023 |archive-date=13 June 2023 |archive-url=https://web.archive.org/web/20230613022543/http://www.ub.edu/hcub/hfq/sites/default/files/ruth1914(5).pdf |url-status=live }}</ref><ref>{{cite book |last1=Whittaker |first1=Edmund |title=A History of the Theories of Aether and Electricity |date=1989 |volume=2 |publisher=Courier Dover Publications |isbn=0-486-26126-3 |page=87}}</ref>

It was not until 1919 that Rutherford expanded upon his theory of the "positive electron" with a series of experiments beginning shortly before the end of his time at Manchester. He found that nitrogen, and other light elements, ejected a proton, which he called a "hydrogen atom", when hit with α (alpha) particles.<ref name="Nobel Rutherford Biography"/> In particular, he showed that particles ejected by alpha particles colliding with hydrogen have unit charge and 1/4 the momentum of alpha particles.<ref>{{cite journal |last1=Rutherford |first1=Ernest |title=LII. Collision of α particles with light atoms II. Velocity of the hydrogen atom |journal=The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science |date=8 April 2009 |volume=37 |issue=222 |pages=562–571 |doi=10.1080/14786440608635917 |url=https://www.tandfonline.com/doi/abs/10.1080/14786440608635917?journalCode=tphm17 |access-date=13 June 2023 |series=6 |archive-date=13 June 2023 |archive-url=https://web.archive.org/web/20230613022542/https://www.tandfonline.com/doi/abs/10.1080/14786440608635917?journalCode=tphm17 |url-status=live }}</ref>

Rutherford returned to the Cavendish Laboratory in 1919, succeeding J. J. Thomson as the Cavendish professor and the laboratory's director, posts that he held until his death in 1937.<ref name=cam>{{cite web |url=http://www.phy.cam.ac.uk/history/cavprof.php |title=The Cavendish Professorship of Physics |publisher=University of Cambridge |accessdate=30 November 2013 |archive-date=3 July 2013 |archive-url=https://web.archive.org/web/20130703172354/http://www.phy.cam.ac.uk/history/cavprof.php |url-status=dead }}</ref> During his tenure, Nobel prizes were awarded to [[James Chadwick]] for discovering the neutron (in 1932), [[John Cockcroft]] and [[Ernest Walton]] for an experiment that was to be known as ''splitting the atom'' using a [[particle accelerator]], and [[Edward Victor Appleton|Edward Appleton]] for demonstrating the existence of the [[ionosphere]].

=== Development of proton and neutron theory ===
In 1919–1920, Rutherford continued his research on the "hydrogen atom" to confirm that alpha particles break down nitrogen nuclei and to affirm the nature of the products. This result showed Rutherford that hydrogen nuclei were a part of nitrogen nuclei (and by inference, probably other nuclei as well). Such a construction had been suspected for many years, on the basis of atomic weights that were integral multiples of that of hydrogen; see [[Prout's hypothesis]]. Hydrogen was known to be the lightest element, and its nuclei presumably the lightest nuclei. Now, because of all these considerations, Rutherford decided that a hydrogen nucleus was possibly a fundamental building block of all nuclei, and also possibly a new fundamental particle as well, since nothing was known to be lighter than that nucleus. Thus, confirming and extending the work of [[Wilhelm Wien]], who in 1898 discovered the proton in streams of [[ionized gas]],<ref>{{Cite journal|doi = 10.1002/andp.18943180404|title = Über positive Elektronen und die Existenz hoher Atomgewichte|journal = Annalen der Physik|volume = 318|issue = 4|pages = 669–677|year = 1904|last1 = Wien|first1 = W.|bibcode = 1904AnP...318..669W|url = https://zenodo.org/record/2190505|access-date = 5 September 2020|archive-date = 13 July 2020|archive-url = https://web.archive.org/web/20200713133516/https://zenodo.org/record/2190505|url-status = live}}</ref> in 1920 Rutherford postulated the hydrogen nucleus to be a new particle, which he dubbed the ''[[proton]]''.<ref>{{cite journal |author=Orme Masson |date=1921 |title=The Constitution of Atoms |journal=The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science |volume=41 |issue=242 |pages=281–285 |doi=10.1080/14786442108636219 |url=https://archive.org/details/londonedinburg6411921lond/page/280/mode/2up }}<br/>Footnote by Ernest Rutherford: 'At the time of writing this paper in Australia, Professor Orme Masson was not aware that the name "proton" had already been suggested as a suitable name for the unit of mass nearly 1, in terms of oxygen 16, that appears to enter into the nuclear structure of atoms. The question of a suitable name for this unit was discussed at an informal meeting of a number of members of Section A of the British Association at Cardiff this year. The name "baron" suggested by Professor Masson was mentioned, but was considered unsuitable on account of the existing variety of meanings. Finally the name "proton" met with general approval, particularly as it suggests the original term "protyle " given by Prout in his well-known hypothesis that all atoms are built up of hydrogen. The need of a special name for the nuclear unit of mass 1 was drawn attention to by Sir Oliver Lodge at the Sectional meeting, and the writer then suggested the name "proton."'</ref>

In 1921, while working with Niels Bohr, Rutherford theorized about the existence of [[neutron]]s, (which he had christened in his 1920 [[Bakerian Lecture]]), which could somehow compensate for the repelling effect of the positive charges of [[proton]]s by causing an attractive [[nuclear force]] and thus keep the nuclei from flying apart, due to the repulsion between protons. The only alternative to neutrons was the existence of "nuclear electrons", which would counteract some of the proton charges in the nucleus, since by then it was known that nuclei had about twice the mass that could be accounted for if they were simply assembled from hydrogen nuclei (protons). But how these nuclear electrons could be trapped in the nucleus, was a mystery.

In 1932, Rutherford's theory of [[neutron]]s was proved by his associate [[James Chadwick]], who recognised neutrons immediately when they were produced by other scientists and later himself, in bombarding beryllium with alpha particles. In 1935, Chadwick was awarded the Nobel Prize in Physics for this discovery.<ref>{{cite web |title=James Chadwick – Facts |url=https://www.nobelprize.org/prizes/physics/1935/chadwick/facts/ |website=The Nobel Prize |publisher=Nobel Prize Outreach AB |access-date=16 June 2023 |archive-date=4 October 2019 |archive-url=https://web.archive.org/web/20191004015954/https://www.nobelprize.org/prizes/physics/1935/chadwick/facts/ |url-status=live }}</ref>

=== Induced nuclear reaction and probing the nucleus ===
In Rutherford's four-part article on the "Collision of α-particles with light atoms" he reported two additional fundamental and far reaching discoveries.<ref name=PaisInwardBound/>{{rp|237}} First, he showed that at high angles the scattering of alpha particles from hydrogen differed from the theoretical results he himself published in 1911. These were the first results to probe the interactions that hold a nucleus together. Second, he showed that α-particles colliding with nitrogen nuclei would react rather than simply bounce off. One product of the reaction was the proton; the other product was shown by [[Patrick Blackett]], Rutherford's colleague and former student, to be oxygen:
:<sup>14</sup>N + α → <sup>17</sup>O + p. 
Rutherford therefore recognised "that the nucleus may increase rather than diminish in mass as the result of collisions in which the proton is expelled".<ref>{{cite journal |last1=Rutherford |first1=Sir Ernest |title=Studies of Atomic Nuclei |url=https://archive.org/details/RoyalInstitutionLibraryOfScience-PhysicalScienceVol9 |date=27 March 1925 |journal=[[Science (journal)|Science]] |volume=62 |issue=1601 |pages=73–76 |publisher=The Royal Institution Library of Sciences |doi=10.1126/science.62.1601.209 |pmid=17748045 |bibcode=1925Sci....62..209R |access-date=2 October 2023}}</ref>
Blackett was awarded the Nobel prize in 1948 for his work in perfecting the high-speed cloud chamber apparatus used to make that discovery and many others.<ref>{{cite journal |title=Nobel Prize for Physics : Prof. P. M. S. Blackett, F.R.S |journal=Nature |volume=162 |issue=4126 |year=1948 |pages=841 |doi=10.1038/162841b0|bibcode=1948Natur.162R.841. |doi-access=free }}</ref>

=== Later years and honours ===
Rutherford received significant recognition in his home country of New Zealand. In 1901, he earned a [[DSc]] from the University of New Zealand.<ref name="Venn" /> In 1916, he was awarded the [[Hector Memorial Medal]].<ref>{{cite web |title=Recipients |url=https://www.royalsociety.org.nz/what-we-do/medals-and-awards/hector-medal/recipients-3/ |publisher=[[Royal Society Te Apārangi]] |access-date=16 February 2021 |archive-date=30 April 2017 |archive-url=https://web.archive.org/web/20170430164858/https://www.royalsociety.org.nz/what-we-do/medals-and-awards/hector-medal/recipients-3/ |url-status=live }}</ref> In 1925, Rutherford called for the [[New Zealand Government]] to support education and research, which led to the formation of the [[Department of Scientific and Industrial Research (New Zealand)|Department of Scientific and Industrial Research (DSIR)]] in the following year.<ref>{{cite web |first=Emma |last=Brewerton |date=15 December 2014 |title=Ernest Rutherford |publisher=Ministry for Culture and Heritage |url=http://www.nzhistory.net.nz/people/ernest-rutherford |access-date=29 December 2010 |archive-date=1 December 2012 |archive-url=https://web.archive.org/web/20121201203746/http://www.nzhistory.net.nz/people/ernest-rutherford |url-status=live }}</ref> In 1933, Rutherford was one of the two inaugural recipients of the [[T. K. Sidey Medal]], which was established by the [[Royal Society of New Zealand]] as an award for outstanding scientific research.<ref>{{cite web |title=Background of the Medal |url=http://www.royalsociety.org.nz/programmes/awards/sidey-medal/background/ |publisher=[[Royal Society of New Zealand]] |access-date=7 August 2015 |archive-date=19 September 2016 |archive-url=https://web.archive.org/web/20160919031437/http://www.royalsociety.org.nz/programmes/awards/sidey-medal/background/ |url-status=live }}</ref><ref>{{cite web |title=Recipients |url=http://www.royalsociety.org.nz/programmes/awards/sidey-medal/recipients/ |publisher=[[Royal Society of New Zealand]] |access-date=7 August 2015 |archive-date=9 April 2017 |archive-url=https://web.archive.org/web/20170409021241/http://royalsociety.org.nz/programmes/awards/sidey-medal/recipients/ |url-status=live }}</ref>

Additionally, Rutherford received a number of awards from the British Crown. He was [[Knight Bachelor|knighted]] in 1914.<ref>{{London Gazette |issue=12647 |date=27 February 1914 |page=269 |city=Edinburgh}}</ref> He was appointed to the [[Order of Merit]] in the [[1925 New Year Honours]].<ref>{{London Gazette |issue=14089 |date=2 January 1925 |page=4 |city=Edinburgh}}</ref> Between 1925 and 1930, he served as [[President of the Royal Society]], and later as president of the [[Council for Assisting Refugee Academics|Academic Assistance Council]] which helped almost 1,000 university refugees from Germany.<ref name="eb"/> In 1931 was raised to Baron of the United Kingdom under the title '''Baron Rutherford of Nelson''',<ref>{{London Gazette |issue=33683 |date=23 January 1931 |page=533}}</ref> decorating his coat of arms with a [[Kiwi (bird)|kiwi]] and a [[Māori culture|Māori]] warrior.<ref>{{cite web |title=Ernest Rutherford – Biography |url=https://nzhistory.govt.nz/people/ernest-rutherford |website=New Zealand History |access-date=23 June 2023 |archive-date=23 June 2023 |archive-url=https://web.archive.org/web/20230623110402/https://nzhistory.govt.nz/people/ernest-rutherford |url-status=live }}</ref> The title became extinct upon his unexpected death in 1937.

Since 1992 his portrait appears on the [[New Zealand one hundred-dollar note]].