Name: Sir J. J. Thomson
Date of Birth: December 18, 1856
Place of Birth: Cheetham Hill, Manchester, England
Date of Death: 30 August 1940 (aged 83)
Honors:
Smith's Prize (1880)
Royal Medal (1894)
Hughes Medal (1902)
Nobel Prize in Physics (1906)
Elliott Cresson Medal (1910)
Copley Medal (1914)
Albert Medal (1915)
Franklin Medal (1922)
Faraday Medal (1925)
Contribution to Physics:
J.J. Thomson discovered the existence of the electron, a negatively-charged particle that's 1/2000 the relative size of the proton. Before this, people thought that atoms were the smallest possible size of anything in existence, so this meant that there were even smaller particles that made up atoms. Because it was known as a fact that atoms were electrically neutral, J.J. Thomson proposed the ‘Plum Pudding' model of the atom, where an atom was a positively-charged mass embedded with many negatively-charged electrons, like the bits of plum in the pudding. The embedded electrons made the overall charge of the atom neutral, or non-existent.