Ernest Rutherford

Ernest Rutherford, 1st Baron Rutherford of Nelson, OM, FRS[2] HFRSE LLD (30 August 1871 – 19 October 1937), was a New Zealand-born British physicist who came to be known as the father of nuclear physics.[3] Encyclopædia Britannica considers him to be the greatest experimentalist since Michael Faraday (1791–1867).[3]

In early work, Rutherford discovered the concept of radioactive half-life, the radioactive element radon,[4] and differentiated and named alpha and beta radiation.[5] This work was performed at McGill University in Canada. It is the basis for the Nobel Prize in Chemistry he was awarded in 1908 "for his investigations into the disintegration of the elements, and the chemistry of radioactive substances",[6] for which he was the first Canadian and Oceanian Nobel laureate.

Rutherford moved in 1907 to the Victoria University of Manchester (today University of Manchester) in the UK, where he and Thomas Royds proved that alpha radiation is helium nuclei.[7][8] Rutherford performed his most famous work after he became a Nobel laureate.[6] In 1911, although he could not prove that it was positive or negative,[9] he theorized that atoms have their charge concentrated in a very small nucleus,[10] and thereby pioneered the Rutherford model of the atom, through his discovery and interpretation of Rutherford scattering by the gold foil experiment of Hans Geiger and Ernest Marsden. He conducted research that led to the first "splitting" of the atom in 1917 in a nuclear reaction between nitrogen and alpha particles, in which he also discovered (and named) the proton.[11]

Rutherford became Director of the Cavendish Laboratory at the University of Cambridge in 1919. Under his leadership the neutron was discovered by James Chadwick in 1932 and in the same year the first experiment to split the nucleus in a fully controlled manner was performed by students working under his direction, John Cockcroft and Ernest Walton. After his death in 1937, he was honoured by being interred with the greatest scientists of the United Kingdom, near Sir Isaac Newton's tomb in Westminster Abbey. The chemical element rutherfordium (element 104) was named after him in 1997.


The Lord Rutherford of Nelson

Ernest Rutherford LOC
President of the Royal Society
In office
1925–1930
Preceded bySir Charles Scott Sherrington
Succeeded bySir Frederick Gowland Hopkins
Personal details
Born30 August 1871
Brightwater, New Zealand
Died19 October 1937 (aged 66)
Cambridge, England
CitizenshipBritish subject
NationalityNew Zealander
ResidenceNew Zealand, United Kingdom
Signature
Ernest Rutherford's signature
Alma materCanterbury College, University of New Zealand
University of Cambridge
Known for
Awards
Scientific career
FieldsPhysics and chemistry
InstitutionsMcGill University
University of Manchester
University of Cambridge
Academic advisorsAlexander Bickerton
J. J. Thomson[1]
Doctoral students
Other notable students
InfluencedHenry Moseley
Hans Geiger
Albert Beaumont Wood

Biography

Early life and education

Ernest Rutherford 1892
Rutherford aged 21

Ernest Rutherford was the son of James Rutherford, a farmer, and his wife Martha Thompson, originally from Hornchurch, Essex, England.[12] James had emigrated to New Zealand from Perth, Scotland, "to raise a little flax and a lot of children". Ernest was born at Brightwater, near Nelson, New Zealand. His first name was mistakenly spelled 'Earnest' when his birth was registered.[13] Rutherford's mother Martha Thompson was a schoolteacher.[14]

He studied at Havelock School and then Nelson College and won a scholarship to study at Canterbury College, University of New Zealand, where he participated in the debating society and played rugby.[15] After gaining his BA, MA and BSc, and doing two years of research during which he invented a new form of radio receiver, in 1895 Rutherford was awarded an 1851 Research Fellowship from the Royal Commission for the Exhibition of 1851,[16] to travel to England for postgraduate study at the Cavendish Laboratory, University of Cambridge.[17] He was among the first of the 'aliens' (those without a Cambridge degree) allowed to do research at the university, under the inspiring leadership of J. J. Thomson, which aroused jealousies from the more conservative members of the Cavendish fraternity. With Thomson's encouragement, he managed to detect radio waves at half a mile and briefly held the world record for the distance over which electromagnetic waves could be detected, though when he presented his results at the British Association meeting in 1896, he discovered he had been outdone by another lecturer, by the name of Marconi.

In 1898, Thomson recommended Rutherford for a position at McGill University in Montreal, Canada. He was to replace Hugh Longbourne Callendar who held the chair of Macdonald Professor of physics and was coming to Cambridge.[18] Rutherford was accepted, which meant that in 1900 he could marry Mary Georgina Newton (1876–1954)[19][20] to whom he had become engaged before leaving New Zealand; they married at St Paul's Anglican Church, Papanui in Christchurch,[21][22] they had one daughter, Eileen Mary (1901–1930), who married Ralph Fowler. In 1901, he gained a DSc from the University of New Zealand.[17] In 1907, Rutherford returned to Britain to take the chair of physics at the Victoria University of Manchester.

Later years and honours

He was knighted in 1914.[23] During World War I, he worked on a top secret project to solve the practical problems of submarine detection by sonar.[24] In 1916, he was awarded the Hector Memorial Medal. In 1919, he returned to the Cavendish succeeding J. J. Thomson as the Cavendish professor and Director. Under him, Nobel Prizes were awarded to James Chadwick for discovering the neutron (in 1932), John Cockcroft and Ernest Walton for an experiment which was to be known as splitting the atom using a particle accelerator, and Edward Appleton for demonstrating the existence of the ionosphere. In 1925, Rutherford pushed calls to the Government of New Zealand to support education and research, which led to the formation of the Department of Scientific and Industrial Research (DSIR) in the following year.[25] Between 1925 and 1930, he served as President of the Royal Society, and later as president of the Academic Assistance Council which helped almost 1,000 university refugees from Germany.[3] He was appointed to the Order of Merit in the 1925 New Year Honours[26] and raised to the peerage as Baron Rutherford of Nelson, of Cambridge in the County of Cambridge in 1931,[27] a title that became extinct upon his unexpected death in 1937. In 1933, Rutherford was one of the two inaugural recipients of the T. K. Sidey Medal, set up by the Royal Society of New Zealand as an award for outstanding scientific research.[28][29]

SirErnieWestminster
Lord Rutherford's grave in Westminster Abbey

For some time before his death, Rutherford had a small hernia, which he had neglected to have fixed, and it became strangulated, causing him to be violently ill. Despite an emergency operation in London, he died four days afterwards of what physicians termed "intestinal paralysis", at Cambridge.[30] After cremation at Golders Green Crematorium,[30] he was given the high honour of burial in Westminster Abbey, near Isaac Newton and other illustrious British scientists.[31]

Scientific research

Ernest Rutherford 1905
Ernest Rutherford at McGill University in 1905

At Cambridge, Rutherford started to work with J. J. Thomson on the conductive effects of X-rays on gases, work which led to the discovery of the electron which Thomson presented to the world in 1897. Hearing of 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, he coined the terms alpha ray and beta ray in 1899 to describe the two distinct types of radiation. He then discovered that thorium gave off a gas which produced an emanation which was itself radioactive and would coat other substances. He found that a sample of this radioactive material of any size invariably took the same amount of time for half the sample to decay – its "half-life" (11½ minutes in this case).

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 thorium emanations. Once he had eliminated all the normal chemical reactions, Soddy suggested that it must be one of the inert gases, which they named thoron (later found to be an isotope of radon). They also found another type of thorium they called Thorium X, and kept on finding traces of helium. They also worked with samples of "Uranium X" from William Crookes and radium from Marie Curie.

In 1903, they published their "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. The Nobel Prize in Chemistry 1908 was awarded to Ernest Rutherford "for his investigations into the disintegration of the elements, and the chemistry of radioactive substances".

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. 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 Manchester, he continued to work with alpha radiation. In conjunction with Hans Geiger, he developed zinc sulfide scintillation screens and ionisation chambers to count alphas. By dividing the total charge they produced by the number counted, Rutherford decided that the charge on the alpha was two. In late 1907, Ernest Rutherford and Thomas Royds allowed alphas to penetrate a very thin window into an evacuated tube. As they 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.

Gold foil experiment

Gold foil experiment conclusions
Top: Expected results: alpha particles passing through the plum pudding model of the atom undisturbed.
Bottom: Observed results: a small portion of the particles were deflected, indicating a small, concentrated charge. Note that the image is not to scale; in reality the nucleus is vastly smaller than the electron shell.

Rutherford performed his most famous work after receiving the Nobel prize in 1908. Along with Hans Geiger and Ernest Marsden in 1909, he carried out the Geiger–Marsden experiment, which demonstrated the nuclear nature of atoms by deflecting alpha particles passing through a thin gold foil. Rutherford was inspired to ask Geiger and Marsden in this experiment to look for alpha particles with very high deflection angles, of a type not expected from any theory of matter at that time. Such deflections, though rare, were found, and proved to be a smooth but high-order function of the deflection angle. It was Rutherford's interpretation of this data that led him to formulate the Rutherford model of the atom in 1911 – that a very small charged[9] nucleus, containing much of the atom's mass, was orbited by low-mass electrons.

In 1919–1920, Rutherford found that nitrogen and other light elements ejected a proton (Rutherford said "a hydrogen atom" rather than "a proton") when hit with α (alpha) particles.[32] 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 which were whole numbers 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 from the nucleus that was lighter. Thus, confirming and extending the work of Wilhelm Wien who in 1898 discovered the proton in streams of ionized gas,[33] Rutherford postulated the hydrogen nucleus to be a new particle in 1920, which he dubbed the proton.

In 1921, while working with Niels Bohr (who postulated that electrons moved in specific orbits), Rutherford theorized about the existence of neutrons, (which he had christened in his 1920 Bakerian Lecture), which could somehow compensate for the repelling effect of the positive charges of protons by causing an attractive nuclear force and thus keep the nuclei from flying apart from 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.

Rutherford's theory of neutrons was proved in 1932 by his associate James Chadwick, who recognized 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.

Legacy

Sir Ernest Rutherford - Plaque at the University of Manchester
A plaque commemorating Rutherford's presence at the University of Manchester

Nuclear physics

Rutherford's research, and work done under him as laboratory director, established the nuclear structure of the atom and the essential nature of radioactive decay as a nuclear process. Patrick Blackett, a research fellow working under Rutherford, using natural alpha particles, demonstrated induced nuclear transmutation. Rutherford's team later, using protons from an accelerator, demonstrated artificially-induced nuclear reactions and transmutation. He is known as the father of nuclear physics. Rutherford died too early to see Leó Szilárd's idea of controlled nuclear chain reactions come into being. However, a speech of Rutherford's about his artificially-induced transmutation in lithium, printed in 12 September 1933 London paper The Times, was reported by Szilárd to have been his inspiration for thinking of the possibility of a controlled energy-producing nuclear chain reaction. Szilard had this idea while walking in London, on the same day.

Rutherford's speech touched on the 1932 work of his students John Cockcroft and Ernest Walton in "splitting" lithium into alpha particles by bombardment with protons from a particle accelerator they had constructed. Rutherford realized that the energy released from the split lithium atoms was enormous, but he also realized that the energy needed for the accelerator, and its essential inefficiency in splitting atoms in this fashion, made the project an impossibility as a practical source of energy (accelerator-induced fission of light elements remains too inefficient to be used in this way, even today). Rutherford's speech in part, read:

We might in these processes obtain very much more energy than the proton supplied, but on the average we could not expect to obtain energy in this way. It was a very poor and inefficient way of producing energy, and anyone who looked for a source of power in the transformation of the atoms was talking moonshine. But the subject was scientifically interesting because it gave insight into the atoms.[34]

Items named in honour of Rutherford's life and work

Statue of Ernest Rutherford
A statue of a young Ernest Rutherford at his memorial in Brightwater, New Zealand.
Scientific discoveries
Institutions
Awards
Buildings
Major streets
Other

Incidences of cancer at Rutherford's former laboratory

The Coupland Building at Manchester University, at which Rutherford conducted many of his experiments, has been the subject of a cancer cluster investigation. There has been a statistically high incidence of pancreatic cancer, brain cancer, and motor neuron disease occurring in and around Rutherford's former laboratories and, since 1984, a total of six workers have been stricken with these ailments. In 2009, an independent commission concluded that the very slightly elevated levels of various radiation related to Rutherford's experiments decades earlier are not the likely cause of such cancers and ruled the illnesses a coincidence.[40]

Publications

  • Radio-activity (1904), 2nd ed. (1905), ISBN 978-1-60355-058-1
  • Radioactive Transformations (1906), ISBN 978-1-60355-054-3
  • Radioactive Substances and their Radiations (1913)[41]
  • The Electrical Structure of Matter (1926)
  • The Artificial Transmutation of the Elements (1933)
  • The Newer Alchemy (1937)

Articles

Styles of address and arms

Styles of address

  • 1871-1903: Mr Ernest Rutherford
  • 1903-1914: Mr Ernest Rutherford FRS
  • 1914-1925: Sir Ernest Rutherford FRS
  • 1925: Sir Ernest Rutherford OM FRS
  • 1925-1930: Sir Ernest Rutherford OM PRS
  • 1930-1931: Sir Ernest Rutherford OM FRS
  • 1931-1937: The Right Honourable The Lord Rutherford of Nelson OM FRS

Arms

See also

References

  1. ^ Ernest Rutherford and Frederick Soddy American Physical Society 2017
  2. ^ Eve, A. S.; Chadwick, J. (1938). "Lord Rutherford 1871–1937". Obituary Notices of Fellows of the Royal Society. 2 (6): 394. doi:10.1098/rsbm.1938.0025.
  3. ^ a b c "Ernest Rutherford, Baron Rutherford of Nelson". Encyclopædia Britannica.
  4. ^ Nicholas P. Cheremisinoff (20 April 2016). Pollution Control Handbook for Oil and Gas Engineering. Wiley. pp. 886–. ISBN 978-1-119-11788-9.
  5. ^ "The Discovery of Radioactivity". lbl.gov. 9 August 2000.
  6. ^ a b "Ernest Rutherford – Biography". NobelPrize.org. Retrieved 21 February 2013.
  7. ^ Campbell, John. "Rutherford – A Brief Biography". Rutherford.org.nz. Retrieved 4 March 2013.
  8. ^ Rutherford, E.; Royds, T. (1908). "XXIV.Spectrum of the radium emanation". Philosophical Magazine. Series 6. 16 (92): 313. doi:10.1080/14786440808636511.
  9. ^ a b Rutherford, Ernest (1911). "The scattering of alpha and beta particles by matter and the structure of the atom". Philosophical Magazine. 21: 669.
  10. ^ Longair, M. S. (2003). Theoretical concepts in physics: an alternative view of theoretical reasoning in physics. Cambridge University Press. pp. 377–378. ISBN 978-0-521-52878-8.
  11. ^ Ernest Rutherford | NZHistory.net.nz, New Zealand history online. Nzhistory.net.nz (19 October 1937). Retrieved on 2011-01-26.
  12. ^ McLintock, A.H. (18 September 2007). "Rutherford, Sir Ernest (Baron Rutherford of Nelson, O.M., F.R.S.)". An Encyclopaedia of New Zealand (1966 ed.). Te Ara – The Encyclopedia of New Zealand. ISBN 978-0-478-18451-8. Retrieved 2 April 2008.
  13. ^ Campbell, John. "Rutherford, Ernest 1871–1937". Dictionary of New Zealand Biography. Ministry for Culture and Heritage. Retrieved 4 April 2011.
  14. ^ By J.L. Heilbron - Ernest Rutherford And the Explosion of Atoms - Oxford University Press - ISBN 0-19-512378-6
  15. ^ Campbell, John (30 October 2012). "Rutherford, Ernest". An Encyclopaedia of New Zealand. Te Ara – The Encyclopaedia of New Zealand. Retrieved 1 October 2013.
  16. ^ 1851 Royal Commission Archives
  17. ^ a b "Rutherford, Ernest (RTRT895E)". A Cambridge Alumni Database. University of Cambridge.
  18. ^ McKown, Robin (1962). Giant of the Atom, Ernest Rutherford. Julian Messner Inc, New York. p. 57.
  19. ^ TEARA:The Encyclopedia of New Zealand Story: Rutherford, Ernest
  20. ^ Birth, Death and Marriage Historical Records, New Zealand Government Registration number 1954/19483
  21. ^ "Family history in from the cold". 18 March 2009.
  22. ^ Summerfield, Fiona (9 November 2012). "Historic St Paul's Church in the Christchurch suburb of Papanui is being fully restored". Anglican Taonga.
  23. ^ "No. 12647". The Edinburgh Gazette. 27 February 1914. p. 269.
  24. ^ Alan Selby (9 November 2014). "Manchester scientist Ernest Rutherford revealed as top secret mastermind behind sonar technology". Manchester Evening News. Retrieved 13 November 2014.
  25. ^ Brewerton, Emma (15 December 2014). "Ernest Rutherford". Ministry for Culture and Heritage.
  26. ^ "No. 14089". The Edinburgh Gazette. 2 January 1925. p. 4.
  27. ^ "No. 33683". The London Gazette. 23 January 1931. p. 533.
  28. ^ "Background of the Medal". Royal Society of New Zealand. Retrieved 7 August 2015.
  29. ^ "Recipients". Royal Society of New Zealand. Retrieved 7 August 2015.
  30. ^ a b The Complete Peerage, Volume XIII – Peerage Creations, 1901–1938. St Catherine's Press. 1949. p. 495.
  31. ^ Heilbron, J. L. (2003) Ernest Rutherford and the Explosion of Atoms. Oxford: Oxford University Press. pp. 123–124. ISBN 0-19-512378-6.
  32. ^ "Atop the Physics Wave: Rutherford back in Cambridge, 1919–1937". Rutherford's Nuclear World: The Story of the Discovery of the Nucleus. American Institute of Physics. Retrieved 25 June 2018.
  33. ^ Wilhelm Wien: Über positive Elektronen und die Existenz hoher Atomgewichte. In: Annalen der Physik. Band 318 (4), 1904, S. 669–677.
  34. ^ The Times archives, 12 September 1933, "The British association – breaking down the atom"
  35. ^ Freemantle, Michael (2003). "ACS Article on Rutherfordium". Chemical & Engineering News. American Chemical Society. Retrieved 2 April 2008.
  36. ^ "Rutherford House History". Nelson College. Nelson College. Retrieved 1 April 2018.
  37. ^ "ErnestRutherford Physics Building". Virtual McGill. McGill University. 24 January 2000. Retrieved 2 April 2008.
  38. ^ Lord Rutherford may have left a deadly legacy « Lord Rutherford may have left a deadly legacy « News « Royal Society of New Zealand Archived 14 October 2008 at the Wayback Machine. Royalsociety.org.nz. Retrieved on 26 January 2011.
  39. ^ "'Good Kiwi men' reflected in chapel window". Hawke's Bay Today. NZPA. 25 July 2007. Retrieved 6 December 2016.
  40. ^ Brumfiel, Geoff (30 September 2009). "Rutherford Building cancers a 'coincidence'". Nature. doi:10.1038/news.2009.965.
  41. ^ Carmichael, R. D. (1916). "Review" Radioactive Substances and their Radiations, by E. Rutherford" (PDF). Bull. Amer. Math. Soc. 22 (4): 200. doi:10.1090/s0002-9904-1916-02762-5.
  42. ^ Pais, Abraham (1999). Line of Succession: Heraldry of the Royal Families of Europe. Oxford: Oxford University Press. p. 216. ISBN 978-0-19-851997-3.
  43. ^ "Coat-of-Arms of Ernest Rutherford". Escutcheons of Science. Numericana.

Further reading

External links

Peerage of the United Kingdom
New creation Baron Rutherford of Nelson
1931–1937
Extinct
Artificial disintegration

Artificial disintegration is the term coined by Ernest Rutherford for the process by which an atomic nucleus is broken down by bombarding it with high speed alpha particles, either from a particle accelerator, or a naturally decaying radioactive substance such as radium, as Rutherford originally used.

Atomic energy

Atomic energy is energy carried by atoms. The term originated in 1903 when Ernest Rutherford began to speak of the possibility of atomic energy. The term was popularized by H. G. Wells in the phrase, "splitting the atom", devised at a time prior to the discovery of the nucleus. Atomic energy may include:

Nuclear binding energy, the energy required to split a nucleus of an atom.

Nuclear potential energy, the potential energy of the particles inside an atomic nucleus.

Nuclear reaction, a process in which nuclei or nuclear particles interact, resulting in products different from the initial ones; see also nuclear fission and nuclear fusion.

Radioactive decay, the set of various processes by which unstable atomic nuclei (nuclides) emit subatomic particles.

The energy of inter-atomic or chemical bonds, which holds atoms together in compounds.Atomic energy is the source of nuclear power, which uses sustained nuclear fission to generate heat and electricity.

Atomic nucleus

The atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom, discovered in 1911 by Ernest Rutherford based on the 1909 Geiger–Marsden gold foil experiment. After the discovery of the neutron in 1932, models for a nucleus composed of protons and neutrons were quickly developed by Dmitri Ivanenko and Werner Heisenberg. An atom is composed of a positively-charged nucleus, with a cloud of negatively-charged electrons surrounding it, bound together by electrostatic force. Almost all of the mass of an atom is located in the nucleus, with a very small contribution from the electron cloud. Protons and neutrons are bound together to form a nucleus by the nuclear force.

The diameter of the nucleus is in the range of 1.7566 fm (1.7566×10−15 m) for hydrogen (the diameter of a single proton) to about 11.7142 fm for the heaviest atom uranium. These dimensions are much smaller than the diameter of the atom itself (nucleus + electron cloud), by a factor of about 26,634 (uranium atomic radius is about 156 pm (156×10−12 m)) to about 60,250 (hydrogen atomic radius is about 52.92 pm).The branch of physics concerned with the study and understanding of the atomic nucleus, including its composition and the forces which bind it together, is called nuclear physics.

Cavendish Professor of Physics

The Cavendish Professorship is one of the senior faculty positions in physics at the University of Cambridge. It was founded on 9 February 1871 alongside the famous Cavendish Laboratory, which was completed three years later. William Cavendish, 7th Duke of Devonshire endowed both the professorship and laboratory in honor of his relative, chemist and physicist Henry Cavendish.

Ernest Marsden

Sir Ernest Marsden (19 February 1889 – 15 December 1970) was an English-New Zealand physicist. He is recognised internationally for his contributions to science while working under Ernest Rutherford, which led to the discovery of new theories on the structure of the atom. In Marsden's later work in New Zealand, he became a significant member of the scientific community, while maintaining close links to the United Kingdom.

Frederick Soddy

Frederick Soddy FRS (2 September 1877 – 22 September 1956) was an English radiochemist who explained, with Ernest Rutherford, that radioactivity is due to the transmutation of elements, now known to involve nuclear reactions. He also proved the existence of isotopes of certain radioactive elements.

Geiger–Marsden experiment

The Geiger–Marsden experiments (also called the Rutherford gold foil experiment) were a landmark series of experiment by which scientists discovered that every atom contains a nucleus where all of its positive charge and most of its mass are concentrated. They deduced this by measuring how an alpha particle beam is scattered when it strikes a thin metal foil. The experiments were performed between 1908 and 1913 by Hans Geiger and Ernest Marsden under the direction of Ernest Rutherford at the Physical Laboratories of the University of Manchester.

George Laurence

George Craig Laurence (21 January 1905 – 6 November 1987) was a Canadian nuclear physicist. He was educated at Dalhousie University, and at Cambridge University under Ernest Rutherford.He was appointed as Radium and X-ray physicist to the Canadian National Research Council in 1930. In 1939-40 he attempted to build a graphite-uranium reactor in Ottawa, anticipating Enrico Fermi's work by several months. In 1942 he joined the Anglo-French nuclear research team at the Montreal Laboratory, where he was responsible for recruiting Canadian scientists. The laboratory later transferred to the Chalk River, and built the ZEEP Reactor, the first outside the U.S.A.

In 1946-47 he was in the Canadian delegation to the United Nations Atomic Energy Commission. He then returned to Montreal Laboratory and continued to carry out his research from 1950 to 1961. He was then at the Chalk River Laboratory, and was President of the Atomic Energy Control Board from 1961 to 1970.

Laurence Court, a street in Deep River, Ontario, is named in his honour.

Harriet Brooks

Harriet Brooks (July 2, 1876 – April 17, 1933) was the first Canadian female nuclear physicist. She is most famous for her research on nuclear transmutations and radioactivity. Ernest Rutherford, who guided her graduate work, regarded her as being next to Marie Curie in the calibre of her aptitude. She was among the first persons to discover radon and to try to determine its atomic mass.

Institute of Physics Ernest Rutherford Medal and Prize

The Ernest Rutherford Medal and Prize is a subject award of the Institute of Physics, presented once every two years for distinguished research in nuclear physics or nuclear technology.

Matteucci Medal

The Matteucci Medal is an Italian award for physicists, named after Carlo Matteucci. It was established to award physicists for their fundamental contributions. Under an Italian Royal Decree dated July 10, 1870, the Italian Society of Sciences was authorized to receive a donation from Carlo Matteucci for the establishment of the Prize.

Matteucci MedalistsSource: Italian Society of Sciences

Rutherford (Martian crater)

Rutherford is an impact crater on Mars. It is located the Oxia Palus quadrangle inside Arabia Terra at 19.2° N and 10.7° W. and measures approximately 107 kilometers in diameter. The crater was named after British physicist Ernest Rutherford in 1973.

Rutherford (unit)

The rutherford (symbol Rd) is a non-SI unit of radioactive decay. It is defined as the activity of a quantity of radioactive material in which one million nuclei decay per second. It is therefore equivalent to one megabecquerel, and one becquerel equals one microrutherford. One rutherford is equivalent to 2.703 × 10−5 curie.

The unit was introduced in 1946. It was named after British/New Zealand physicist and Nobel laureate Lord Ernest Rutherford (Nobel Prize in 1908), who was an early leader in the study of atomic nucleus disintegrations. After the becquerel was introduced in 1975 as the SI unit for activity, the rutherford became obsolete, and it is no longer commonly used.

Rutherford Medal (Royal Society of New Zealand)

For other similarly named awards, see Rutherford Medal

The Rutherford Medal (instituted in 1991 and known as the New Zealand Science and Technology Gold Medal until 2000) is the most prestigious award offered by the Royal Society of New Zealand, consisting of a medal and prize of $100,000. It is awarded at the request of the New Zealand Government to recognize exceptional contributions to the advancement and promotion of public awareness, knowledge and understanding in addition to eminent research or technological practice by a person or group in any field of science, mathematics, social science, or technology. It is funded by the New Zealand government and awarded annually.

The medal is named after Ernest Rutherford, the New Zealand experimental physicist and Nobel Laureate, who pioneered the orbital theory of the atom.

Rutherford Memorial Medal

The Rutherford Memorial Medal is an award for research in the fields of physics and chemistry by the Royal Society of Canada. It was dedicated to the memorial of Ernest Rutherford.

Rutherford model

The Rutherford model, also known as planetary model is a model which tried to describe an atom devised by Ernest Rutherford. Rutherford directed the famous Geiger–Marsden experiment in 1909 which suggested, upon Rutherford's 1911 analysis, that J. J. Thomson's plum pudding model of the atom was incorrect. Rutherford's new model for the atom, based on the experimental results, contained new features of a relatively high central charge concentrated into a very small volume in comparison to the rest of the atom and with this central volume also containing the bulk of the atomic mass of the atom. This region would be known as the "nucleus" of the atom.

Rutherford scattering

Rutherford scattering is the elastic scattering of charged particles by the Coulomb interaction. It is a physical phenomenon explained by Ernest Rutherford in 1911 that led to the development of the planetary Rutherford model of the atom and eventually the Bohr model. Rutherford scattering was first referred to as Coulomb scattering because it relies only upon the static electric (Coulomb) potential, and the minimum distance between particles is set entirely by this potential. The classical Rutherford scattering process of alpha particles against gold nuclei is an example of "elastic scattering" because neither the alpha particles nor the gold nuclei are internally excited. The Rutherford formula (see below) further neglects the recoil kinetic energy of the massive target nucleus.

The initial discovery was made by Hans Geiger and Ernest Marsden in 1909 when they performed the gold foil experiment in collaboration with Rutherford, in which they fired a beam of alpha particles (helium nuclei) at foils of gold leaf only a few atoms thick. At the time of the experiment, the atom was thought to be analogous to a plum pudding (as proposed by J. J. Thomson), with the negatively-charged electrons (the plums) studded throughout a positive spherical matrix (the pudding). If the plum-pudding model were correct, the positive "pudding", being more spread out than in the correct model of a concentrated nucleus, would not be able to exert such large coulombic forces, and the alpha particles should only be deflected by small angles as they pass through.

However, the intriguing results showed that around 1 in 8000 alpha particles were deflected by very large angles (over 90°), while the rest passed through with little deflection. From this, Rutherford concluded that the majority of the mass was concentrated in a minute, positively-charged region (the nucleus) surrounded by electrons. When a (positive) alpha particle approached sufficiently close to the nucleus, it was repelled strongly enough to rebound at high angles. The small size of the nucleus explained the small number of alpha particles that were repelled in this way. Rutherford showed, using the method outlined below, that the size of the nucleus was less than about 10−14 m (how much less than this size, Rutherford could not tell from this experiment alone; see more below on this problem of lowest possible size). As a visual example, Figure 1 shows the deflection of an alpha particle by a nucleus in the gas of a cloud chamber.

Rutherford scattering is now exploited by the materials science community in an analytical technique called Rutherford backscattering.

Rutherfordium

Rutherfordium is a synthetic chemical element with symbol Rf and atomic number 104, named after physicist Ernest Rutherford. As a synthetic element, it is not found in nature and can only be created in a laboratory. It is radioactive; the most stable known isotope, 267Rf, has a half-life of approximately 1.3 hours.

In the periodic table of the elements, it is a d-block element and the second of the fourth-row transition elements. It is a member of the 7th period and belongs to the group 4 elements. Chemistry experiments have confirmed that rutherfordium behaves as the heavier homologue to hafnium in group 4. The chemical properties of rutherfordium are characterized only partly. They compare well with the chemistry of the other group 4 elements, even though some calculations had indicated that the element might show significantly different properties due to relativistic effects.

In the 1960s, small amounts of rutherfordium were produced in the Joint Institute for Nuclear Research in the former Soviet Union and at Lawrence Berkeley National Laboratory in California. The priority of the discovery and therefore the naming of the element was disputed between Soviet and American scientists, and it was not until 1997 that International Union of Pure and Applied Chemistry (IUPAC) established rutherfordium as the official name for the element.

Subatomic particle

In the physical sciences, subatomic particles are particles much smaller than atoms. The two types of subatomic particles are: elementary particles, which according to current theories are not made of other particles; and composite particles. Particle physics and nuclear physics study these particles and how they interact.

The idea of a particle underwent serious rethinking when experiments showed that light could behave like a stream of particles (called photons) as well as exhibiting wave-like properties. This led to the new concept of wave–particle duality to reflect that quantum-scale "particles" behave like both particles and waves (they are sometimes described as wavicles to reflect this). Another new concept, the uncertainty principle, states that some of their properties taken together, such as their simultaneous position and momentum, cannot be measured exactly. In more recent times, wave–particle duality has been shown to apply not only to photons but to increasingly massive particles as well.Interactions of particles in the framework of quantum field theory are understood as creation and annihilation of quanta of corresponding fundamental interactions. This blends particle physics with field theory.

Coat of arms of Ernest Rutherford
Ernest Rutherford Arms
Notes
The arms of Ernest Rutherford consist of:[42][43]
Crest
A baron's coronet. On a helm wreathed of the Colors, a kiwi Proper.
Escutcheon
Per saltire arched Gules and Or, two inescutcheons voided of the first in fess, within each a martlet Sable.
Supporters
Dexter, Hermes Trismegistus (mythological patron of knowledge and alchemists). Sinister, a Māori warrior.
Motto
Primordia Quaerere Rerum ("To seek the first principles of things." Lucretius.)
17th century
18th century
19th century
20th century
21st century
Recipients of the Copley Medal (1901–1950)
1901–1925
1926–1950
1951–1975
1976–2000
2001–present
Recipients of the Hector Memorial Medal

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