When the atom was first discovered, physicists gave a lot of thought as to what the atom consisted of. J J Thompson proposed the plum [?] model, in which [?] were placed like cherries in a matrix of positive charge. The [?] had not yet been discovered.

Rutherford bombarded a thin layer of gold atoms with particles. He was using the alpha particles like bullets, expecting to see the atoms . He described his experiment as firing artillery shells at tissue paper.

To his surprise he found that some of the alpha particles back in the direction they came from. Other particles went straight though, while other particles were deflected.

This alpha scattering showed some amazing facts about the nucleus:
- The nucleus is very ;
- Most of the atom is [?] space;
- The of the positively charged alpha particle showed that the nucleus is positively charged.