CPB Budapest 2017

Atoms: Thomson ´ s discovery of Electrons

In 1897 Sir Joseph John Thomson (1856-1940) performed his famous experiment with cathode rays, where he proved that cathode radiation can be deflected by electric and magnetic fields and thus consisted of charged particles, the electrons. In the following years several experiments where the scattering of electron beams was studied showed that the largest portion of the space occupied by the atoms is empty. Based on these results Thomson proposed in 1904 that atoms consist of a spherical positive electrical charge distribution, like a liquid, in which the negative charged electrons are moving: the Thomson’s compact atom model.

Thomson ´ s atom model