apr 28, 1899 - Rutherford, Sir Ernest (1871-1937)
Discovered that uranium radiation is composed of positively charged 'alpha' particles and negatively charged 'beta' particles (1989/1899). First to prove radioactive decay of heavy elements and to perform a transmutation reaction (1919). Discovered half-life of radioactive elements. Established that the nucleus was small, dense, and positively charged. Assumed that electrons were outside the nucleus. Nobel Prize in 1908.
