John Joseph Thomson (1856-1940)

Joseph John “J. J.” ThomsonBorn: December, 18 1856 Cheetham Hill, Manchester, UK

Died: 30 August 1940 (aged 83)Cambridge, UK

Nationality: British

Fields: Physics

Institutions: Cambridge University

Alma mater: University of Manchester, University of Cambridge.

Joseph John “J. J.” Thomson

Sir Joseph John “J. J.” Thomson, (18 December 1856 – 30 August 1940) was a British physicist and Nobel laureate. He is credited for the discovery of the electron and of isotopes, and the invention of the mass spectrometer. Thomson was awarded the 1906 Nobel Prize in Physics for the discovery of the electron and for his work on the conduction of electricity in gases.

1897: Physicist J.J. Thomson tells a startled scientific audience that he's discovered something smaller than an atom, a particle with a minuscule mass and a negative charge. As director of Cavendish Laboratory at Cambridge University, Thomson was researching electrical currents inside cathode ray tubes. He observed that the rays are deflected by an electric field.

Researchers had been puzzled by cathode rays until Thomson theorized that the rays were in fact streams of small subatomic particles, the first known. He called them "corpuscles," the Latin for "small bodies."

The electron is discovered, J.J. Thomson publishes his discovery of a sub atomic particle common to all matter. When investigating cathode rays using a highly evacuated discharge tube he was able to use the calculated velocity and deflection of the beam to calculate the ratio of electric charge to mass of the cathode ray.

This was found to be constant regardless of the gas used in the tube and the metal of the cathode and was approximately 1000 times less than the value calculated for hydrogen ions in the electrolysis of liquids.

Cathode Ray Tube

J.J. Thomson’s original Cathode Ray Tube

Modernized Cathode Ray Tube

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