Electron was discovered when extremely low pressures and very high voltages were applied to the electrodes in a cathode ray discharge tube. This led to the release of cathode rays which contained negatively charged particles from the negatively charged electrode i.e. cathode to positively charged electrode i.e. anode.
The following conclusions were made about the cathode rays:
1. The cathode rays travelled from the cathode to anode.
2. They can only be detected if they strike a phosphorescent material ( like ZnS- Zinc Sulphide) as they tend to leave a bright spot on the material.
3. In the absence of electric and magnetic field, they tend to travel in straight lines.
4. In the presence of electric and magnetic field, they tend to deflect which concludes that they contain negatively charged particles i.e. electrons.
5. Their characteristics do not depend on the material of the electrodes as well as the nature of the gas inside the discharge tube.
