#4H.     History of the Electron

The experiment with a pumped-out glass bulb, in which an electric circuit is completed by electrons emitted from a hot wire, is credited to the US inventor Thomas Alva Edison (1847-1931), who patented it in 1883. The phenomenon is known as the "Edison effect" and many electronic devices use it nowadays.

Experiments with beams of negative particles were performed in Britain by Joseph John ("J.J.") Thomson, and led to his conclusion in 1897 that they consisted of lightweight particles with a negative electric charge, nowadays known as electrons. Thomson was awarded the 1906 Nobel Prize.


J.J. Thomson

The word "elektron" in Greek means amber, the yellow fossilized resin of evergreen trees, a "natural plastic material" already known to the ancient Greeks. It was known that when amber was rubbed with dry cloth--producing what now one would call static electricity--it could attract light objects, such as bits of paper.

William Gilbert, a physician who lived in London at the time of Queen Elizabeth I and Shakespeare, studied magnetic phenomena and demonstrated that the Earth itself was a huge magnet, by means of his "terrella" experiment. But he also studied the attraction produced when materials such as amber were rubbed, and named it the "electric" attraction. From that came the word "electricity" and all others derived from it.

Further Reading:

• To mark the 100th anniversary of the discovery of the electron, the Center for History of Physics of the American Institute of Physics has created on the world wide web a suitable exhibit: http://www.aip.org/history/electron.

• Sir George Thomson, J. J. Thomson's son, was a renowned physicist in his own right and won the Nobel prize in 1937. On the 70th anniversary of the discovery of the electron he wrote about that discovery and about later developments where electrons were discovered to act sometimes like waves: "The Septuagenarian Electron", Physics Today, May 1967, 55-61

• The story of J. J. Thomson is also briefly given in the first chapter of "From X-Rays to Quarks" by Emilio Segre (W.H. Freeman and Co., 1980). Segre was a physicist who won the 1959 Nobel Prize and his concise history of modern physics is filled with insights and stories, some of them drawn from his own experience.