Joseph John Thomson

Sir Joseph John Thomson OM PRS
Born	18 December 1856 Cheetham Hill, Manchester, England
Died	30 August 1940(1940-08-30) (aged 83) Cambridge, England
Citizenship	British
Nationality	English
Fields	Physics
Institutions	Trinity College, Cambridge
Alma mater	Owens College Trinity College, Cambridge
Academic advisors	John Strutt (Rayleigh) Edward John Routh
Notable students	Charles Glover Barkla Charles T. R. Wilson Ernest Rutherford Francis William Aston John Townsend J. Robert Oppenheimer Owen Richardson William Henry Bragg H. Stanley Allen John Zeleny Max Born T. H. Laby Paul Langevin Balthasar van der Pol Geoffrey Ingram Taylor Niels Bohr George Paget Thomson
Known for	Plum pudding model Discovery of electron Discovery of isotopes Mass spectrometer invention First m/e measurement Proposed first waveguide Thomson scattering Thomson problem Coining term 'delta ray' Coining term 'epsilon radiation' Thomson (unit)
Notable awards	Smith's Prize (1880) Royal Medal (1894) Hughes Medal (1902) Nobel Prize in Physics (1906) Elliott Cresson Medal (1910) Copley Medal (1914) Albert Medal (1915) Franklin Medal (1922) Faraday Medal (1925)
Signature
Notes
Thomson is the father of Nobel laureate George Paget Thomson.

External video

The Early Life of J.J. Thomson: Computational Chemistry and Gas Discharge Experiments, Profiles in Chemistry, Chemical Heritage Foundation

Sir Joseph John Thomson OM PRS (/ˈtɒmsən/; 18 December 1856 – 30 August 1940) was an English physicist. He was elected as a fellow of the Royal Society of London and appointed to the Cavendish Professorship of Experimental Physics at the Cambridge University's Cavendish Laboratory in 1884.

In 1897, Thomson showed that cathode rays were composed of previously unknown negatively charged particles, which he calculated must have bodies much smaller than atoms and a very large value for their charge-to-mass ratio. Thus he is credited with the discovery and identification of the electron; and with the discovery of the first subatomic particle. Thomson is also credited with finding the first evidence for isotopes of a stable (non-radioactive) element in 1913, as part of his exploration into the composition of canal rays (positive ions). His experiments to determine the nature of positively charged particles, with Francis William Aston, were the first use of mass spectrometry and led to the development of the mass spectrograph.

Thomson was awarded the 1906 Nobel Prize in Physics for his work on the conduction of electricity in gases. Seven of his students, including his son George Paget Thomson, also became Nobel Prize winners either in physics or in chemistry. His record is comparable only to that of the German physicist Arnold Sommerfeld.