J.J. Thomson, an English physicist, took science to new heights with his 1897 discovery of the electron the subatomic particle.
When Thomson began his research career, it was thought that atoms were the smallest particles. Nobody had a clear picture of how atoms might look. It was already known that atoms were associated in some way with electric charges.
In 1897, aged40, Thomson carried out a now famous experiment with a cathode ray tube. His experiment proved the existence of a new fundamental particle that was much smaller than the atom. It was named the electron.
In discovering the electron, Thomson also moved toward the invention of an immensely important new tool for chemical analysis the mass spectrometer.
Then, in 1912, Thomson discovered that stable elements could exist as isotopes. Isotopes are different forms of the same element that exist with different atomic masses.
J.J. Thomson was awarded the Nobel Prize for physics in 1906