Question

What did Rutherford do in his famous experiment?

Answer 1

He fired series of heavy, high energy `alpha-"particles"` at a gold plate.....See here.

Explanation:

Just some background to the experiment. Rutherford initially used gold film. Now all metals are malleable, and gold is extremely malleable amongst metals. The gold film that Rutherford used in the experiment was at most only a few atoms thick (that gold is so malleable, and also beautiful, and it does not tarnish readily, are reasons why gold is prized for jewellery and ornamentation.)

Most of the `alpha-"particles"` passed straight thru the sheet as EXPECTED; a smaller few were deflected; some were reflected by the gold plate back at the `alpha"-particle"` emitter. This last was an extremely unexpected result. To quote Rutherford....

"It was quite the most incredible event that has ever happened to me in my life. It was almost as incredible as if you fired a 15-inch shell at a piece of tissue paper and it came back and hit you."

Rutherford could only account for this finding, by positing that the atoms had a nucleus containing most of the mass of the atom, and ALL of the positive charge, i.e. mass and charge contained in a small nuclear kernel. The nuclear age was born.