Joseph J. Thomson
Thomson lived from 1856-1940. Growing up his father had wanted him to be a engineer but his family could not afford to pay for his apprenticeship. Instead he attended Owen College and eventually was recommended to Trinity College. There he became a mathematical physicist. While teaching there he received a few awards since he was very good at designing apparatus and knowing its problems.
contribution to ATOMIC THEORY |
In 1897 Thomson discovered the electron. Thomson realized the accepted model of an atom didn't show negative or positively charged particles. He came up with a new model of an atom that resembled plum puddings. This model explained some of the electrical properties of the atom.
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EXPERIMENTS AND ATOMIC MODEL |
When he discovered electrons he was conducting a series of experiments that were testing the nature of electric discharge in a high-vacuum cathode-ray tube. He realized that the deflection of rays by electrically charged plates and magnets proved there are electrons. Thomson estimated how many electrons are in each atom by measuring scattered light, beta, X, and gamma rays. The last major experiment he did was on determining nature of positive charged particles which let to mass spectrograph
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