Describe Rutherford’s experience with alpha scattering.

Rutherford’s alpha scattering experiment changed the way we think about atoms. Before the experiment, the best model of the atom was known as the Thomson model. The atom was thought to be composed of positive material with negative ones distributed throughout.

Rutherford directed beams of alpha particles (which are the nuclei of helium atoms and therefore positively charged) into thin gold foil to test this model and noted how alpha particles are scattered from the foil.

Rutherford made 3 observations:

Most of the fast, highly charged alpha particles began to pass right through the undeniable ones.
Some of the alpha particles have been bounced back at large angles.
Very few alpha particles were bent backward.

Rutherford later remarked: “It was as incredible as if you shot a 15-inch shell on a piece of napkin and it came back to you!”