Sir Joseph John Thomson

Thomson, Sir Joseph John (1856–1940), British physicist. The Nobel Prize in physics (1906) was awarded to him for his discovery of the electron. This discovery was made as he studied rays—known as cathode rays—that occurred in a vacuum in a glass tube when electric current was introduced. Eventually he proved that this phenomenon was due to moving particles rather than light rays; those particles were later named electrons. As professor of physics at Cambridge in England, he helped develop their atomic research facilities. His son, Sir George Paget Thomson, also won the Nobel Prize for physics (1937), along with Clinton Davisson of the United States.

See also: Electron.