dec 29, 1896 - Discovery of the Electron

Description:

J.J. Thomson discovered the electron in 1896. J.J. Thomson performed three experiments with cathode ray tubes. First, he used a magnet and electrometer to observe that the cathode rays were indeed electrically charged. Next, he determined that cathode rays were negatively charged by observing them bend away from a negatively charged metal plate and toward a positively charged one. Lastly, by measuring the mass to charge ratio of the cathode rays, he found that they were composed of subatomic particles.