Thompson's Model

What do you think an atom looks like? Most people think an atom resembles a solar system, where the sun (nucleus) is orbited by planets (electrons).    

The ancient Greeks' defined an atom as a small solid sphere, too small to be seen, that cannot be divided into smaller particles. In fact, the word atom comes from the Greek prefix a - (not) and the word tomos (cuttable); a-tomos (not-cuttable).

In 1897, an Englishman named Joseph John Thomson, (1856-1940), known as J.J.Thomson, worked with cathode ray tubes. He determined that the rays from the tube were negatively charged particles, which he called "corpuscles." Today we call these "corpuscles" electrons, and we credit Thomson as their discoverer. Thomson's discovery won him a Nobel Prize in Physics for 1906.

Thomson's model became known as the "plum pudding" model, where the pudding represented a circle of positive charges and the bits of plum scattered in the pudding were the electrons.