J. J. Thomson was a British scientist who, in 1987, discovered the electron. He used a cathode ray tube, some metal plates, and magnets. By experimenting with cathode rays, Thompson was able to discover that there were actually negatively charged particles in the atoms that were already known. Since these particles were about 1000 times smaller than the Hydrogen atom that had already been discovered, Thompson knew that these negatively charged particles were not elements.
Next, Thompson experimented with different types of metals at the start of the cathode ray. He found that, no matter what type of metal is used for this experiment, all metals produce a cathode ray. This was especially important, since that would solidify the notion that negatively charged particles do exist in everything.
Next, Thompson experimented with different types of metals at the start of the cathode ray. He found that, no matter what type of metal is used for this experiment, all metals produce a cathode ray. This was especially important, since that would solidify the notion that negatively charged particles do exist in everything.
This discovery of negatively charged particles, or electrons, led to the new model of the atom - The Plum Pudding Model. This model makes the atom look like one big mass of positively charged energy with electrons just floating freely throughout.