JJ Thomson

Discovered the Electrons By Allison Jordy

Big image

The Discovery of Electrons

In 1897 the British physicist Joseph John (J. J.) Thomson (1856–1940) discovered the Electrons


a series of experiments designed to study the electric discharge in a high-vacuum cathode-ray tube, being investigated by numerous scientists at the time. Thomson interpreted the deflection of the rays by electrically charged plates and magnets as evidence of “bodies much smaller than atoms” he calculated as a very large value for the charge-to-mass ratio. Later he estimated the value of the charge itself. In 1904 he suggested a model of the atom as a sphere of positive matter in which electrons are positioned by electrostatic forces. His last important experimental program focused on determining the nature of positively charged particles. His techniques led to the development of the mass Spirograph.



JJ Thomson,great scientist and physics mentor,became a physicist. His father intended him to be an engineer, which in those days required an apprenticeship, but his family could not raise the money for him to be an engineer. Instead, JJ Thomson attended Owens College, Manchester, which had an excellent science faculty. He was then recommended to Trinity College, Cambridge, where he became a mathematical physicist. Of all the physicists associated with determining the structure of the atom, Thomson remained most closely aligned to the chemical community. His non mathematical atomic theory,unlike early quantum theory—could also be used to account for chemical bonding and molecular structure. In 1913 Thomson published an influential monograph for chemists wanting to use the mass Spirograph in their analyses.

He received various honors, including the Nobel Prize in physics in 1906 and a knighthood in 1908. He also saw several of his close associates receive their own Nobel prizes along with him.

Discovery of the Electron: Cathode Ray Tube Experiment