To download mp3 (audio): Click "Download mp3" button
To Cut/Crop mp3: Please use the slider below and click on "Download mp3" button to download the selected part.
Note that video to mp3 conversion output is limited to 10 minutes.
J.J. Thompson discovered the electron, the first of the subatomic particles, using the cathode ray tube experiment. He found that many different metals release cathode rays, and that cathode rays were made of electrons, very small negatively charged particles. This disproved John Dalton's theory of the atom, and Thompson came up with the plum pudding model of the atom.