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David Nightingale: JJ & GP Thomson

J.J. Thomson
Wikipedia Commons

This essay is about Nobel prize winning fathers and sons in physics, of which there are quite a few, focussing here on JJ Thomson and his son GP Thomson.  JJ is famous for having discovered the electron, and 30 years later his son discovered that it was a wave. Today we can correctly describe all particles, be they electrons or Volkswagens, either way.

This particular Thomson family is spelled without a "P", although to my chagrin I found a well-respected book that managed to give both spellings for the same man [ref.1]. There have been other famous Thomsons spelled with or without the letter "P" -- but one with  a "P" would be the notable Benjamin Thompson of Massachussetts (a.k.a. 'Count Rumford'), but those stories belong elsewhere.

Today we still can't see JJ Thomson's electron -- it's just too small -- way smaller than an atom. But if you had a TV 20 years ago you would be seeing the results of electrons hitting the fluorescent screen -- this was the standard Cathode Ray Tube.

100 years ago atoms were thought by many to be indivisible.  JJ's1890s experiments were about investigating what happens when electricity passes through gases -- nowadays we see this all the time of course, in neon signs for cafes, bars or nightclubs.

JJ finally 'discovered' the electron -- or perhaps we should more accurately say 'clinched and measured its basic properties' -- in and around 1897.

JJ was born in a suburb of Manchester, England, on December 18th, 1856. At age 14 his parents put his name down to be an engineering apprentice. There was a huge waiting list for such apprenticeships and so JJ began attending classes at Owens College -- later Manchester University -- in the interim. The upshot was that he was encouraged by his professors there to try to get entry into Cambridge University, but failed. He tried again a year later, and was accepted. Fortified by a modest scholarship, he remained in Cambridge for the rest of his long and illustrious life. Seven of his students became Nobel prize winners, including Neils Bohr and J.Robert Oppenheimer.

The electron of course is the basic constituent of all electric currents. Yet one of JJ's favorite toasts was "To the electron -- may it never be of any use to anybody."

Continuing JJ's bio -- or perhaps we should be calling him Sir Joseph John Thomson -- he was awarded the 1906 Nobel prize for his researches on the electron. After another 3 decades of physics research in Cambridge he died, in 1940. He is buried not far from Isaac Newton, in Westminster Abbey.

JJ's son, George Paget Thomson, or GP Thomson, was born in 1892, not surprisingly in Cambridge. He studied Mathematics and Physics there, and served briefly in WW1, after which he went to Aberdeen. He was a lecturer at Cornell in 1929-30, and professor of Physics at Imperial College London for the next 22 years. During this time GP demonstrated that electrons could show diffraction patterns, just as light does! This very important result clinched the idea that matter can behave in both wave and particle ways, but we should emphasize that this wave nature for electrons was also discovered quite independently by Clinton Davisson from Illinois (famous worldwide for the Davisson-Germer experiment). Thus both GP Thomson and Davisson shared the 1937 Nobel Prize. (As a semi-irrelevant aside, Germer was a rock climber who died in NY's Gunks in 1971.)

G.P.Thomson died in 1975, aged 83, at essentially the same age his father had reached.

Finally, for interest, I mentioned there have been other father & son Nobel prize winners in physics. These include the families of Neils Bohr, Wm Bragg, and ManneSiegbahn. In addition, if you include mothers and daughters -- plus chemistry -- we can also, of course, add the family of Marie Curie.


1. "Flash of the Cathode Rays; A History of JJ Thomson's Electron", by Per F.Dahl; Institute of Physics Publishing, Suite 1035, The Public Ledger Bldg, 150,  S.Independence Mall West, Philadelphia, PA19106.

2.  Assorted Physics texts.

Dr. David Nightingale is Professor Emeritus of Physics at the State University of New York at New Paltz and is the co-author of the text, A Short Course in General Relativity.

The views expressed by commentators are solely those of the authors. They do not necessarily reflect the views of this station or its management.

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