atomic theory

democritus

400

he theorized everything was made atoms

isaac newton

Oct 1, 1704

Proposed a mechanical universe with small solid masses in motion.

john Dalton

Oct 9, 1803

Proposed an "atomic theory" with spherical solid atoms based upon measurable properties of mass.

michael Faraday

Jan 1, 1832

Studied the effect of electricity on solutions, coined term "electrolysis" as a splitting of molecules with electricity, developed laws of electrolysis. Faraday himself was not a proponent of atomism.

J. plucker

Oct 10, 1859

Built one of the first gas discharge tubes ("cathode ray tube").

G.J. Stoney

Oct 10, 1894

Proposed that electricity was made of discrete negative particles he called electrons ". (Link to info on electrons)

JJ Thompson

Oct 10, 1897

Used a CRT to experimentally determine the charge to mass ratio (e/m) of an electron =1.759 x 10 8 coulombs/gram. "plumb pudding model"

Earnest Rutherford

Oct 10, 1911

Studied radiations emitted from uranium and thorium and named them alpha and beta.Studied uranium and thorium and called their spontaneous decay process "radioactivity". atoms mostly empty