Rutherford’s Scattering Experiment (Also seen in GCSE Physics 2)

Hans Geiger and Ernest Marsden worked with Ernest Rutherford in his Manchester laboratories in 1909. They fired alpha particles (which they knew to have a positive charge) of a few MeV into a thin piece of gold foil. This was done in an evacuated chamber connected to a vacuum pump.

When the alpha particles passed through the gold foil they hit a zinc sulphide screen which emits light whenever an alpha particle strikes it. This screen was observed using a moving microscope in a dark room.

At the time the accepted structure of the atom was like a plum pudding: positive dough spread evenly with negative electrons scattered through out it like plums in a pudding.