jan 1, 1904 - Plum Pudding (Thomson)

Description:

This 'plum pudding' description of an atom was based on prior knowledge that Thomson had received in 1897 when he learned about the electron and its negative charge. He predicted that due to these negative charges he would need positive charges to create a neutral charge. So he made another prediction on the layout of the atom that displayed a ball of positive charge with negatively charged electrons scattered through it like a plum pudding.

Technology enabling him to discover the electrons was an experiment conducted in 1897 including a tube pumped with air with two high voltage electrodes added to either side. He then realized that a ray was coming out of the negatively charged electrode to the positively charged one. This ray was fubbed the cathode ray and allowed for the discovery of the electron.

Due to this experiment, we were able to understand the existence of electrons and protons and build upon the atoms overall structure.

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