J. J. Thomson

Sir Joseph John Thomson (18 December 1856 – 30 August 1940) was an English <a href="/facts/Physicist/cQcgvSIm">physicist</a> who received the <a href="/facts/Nobel_Prize_in_Physics/o6w1nCbr">Nobel Prize in Physics</a> in 1906 "in recognition of the great merits of his theoretical and experimental investigations on the conduction of <a href="/facts/Electricity/hNC8D65W">electricity</a> by <a href="/facts/Gas/hVVAoodV">gases</a>."
In 1897, Thomson showed that <a href="/facts/Cathode_ray/9jRXSquS">cathode rays</a> were composed of previously unknown negatively charged particles (now called <a href="/facts/Electron/L0KBo5cW">electrons</a>), which he calculated must have bodies much smaller than <a href="/facts/Atom/FoQ4kGN5">atoms</a> and a very large <a href="/facts/Charge-to-mass_ratio/QaKpLt6B">charge-to-mass ratio</a>. Thomson is also credited with finding the first evidence for <a href="/facts/Isotope/KD9B1y6o">isotopes</a> of a stable (non-radioactive) element in 1913, as part of his exploration into the composition of <a href="/facts/Canal_ray/MhyobKLc">canal rays</a> (positive ions). His experiments to determine the nature of positively charged particles, with <a href="/facts/Francis_William_Aston/DVoj9ebB">Francis William Aston</a>, were the first use of <a href="/facts/Mass_spectrometry/RH5WBHJ2">mass spectrometry</a> 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. Thomson was also a teacher, and seven of his students went on to win Nobel Prizes: <a href="/facts/Ernest_Rutherford/hjjMEskl">Ernest Rutherford</a> (Chemistry 1908), <a href="/facts/Lawrence_Bragg/MGbHcMPa">Lawrence Bragg</a> (Physics 1915), <a href="/facts/Charles_Barkla/tU7ypwWt">Charles Barkla</a> (Physics 1917), <a href="/facts/Francis_Aston/DVoj9ebB">Francis Aston</a> (Chemistry 1922), <a href="/facts/Charles_Thomson_Rees_Wilson/DlvmMa6u">Charles Thomson Rees Wilson</a> (Physics 1927), <a href="/facts/Owen_Richardson/n0kXDWWw">Owen Richardson</a> (Physics 1928) and <a href="/facts/Edward_Victor_Appleton/7FfJIqz5">Edward Victor Appleton</a> (Physics 1947). Only <a href="/facts/Arnold_Sommerfeld/cJtpVHvn">Arnold Sommerfeld</a>'s record of mentorship offers a comparable list of high-achieving students.

J. J. Thomson open-in-new

J. J. Thomson