Describe Rutherford experiment

Rutherford’s Scattering Experiment

·Rutherford selected a gold foil as he wanted a very thin layer.

·In his experiment, fast moving alpha particles were made to fall on a thin gold foil.

·Alpha particles are helium ions with +2 charge and have a considerable amount of energy.

·These particles were studied by means of flashes of light they produced on striking a zinc sulphide screen.

·He expected the alpha particles to pass through the gold foil with little deflections and strike the fluorescent screen.

But the observations he made were quite unexpected.

·He observed that most of the alpha particles passed straight through the gold foil.

·Some were deflected through small angles and some were deflected through large angles.

·Very few appeared to bounce back.

From the experiment he concluded that-

·As most of the alpha particles passed through the gold foil without getting deflected, most of the space inside the atom is empty.

·Very few particles deflected from their path; this indicated that the positive charge of the atom occupies very little space.

·A small fraction of alpha particles bounced back by 180 degrees, this indicated that the entire positive charge and mass of the atom was concentrated in a very small volume within the atom.

·Based on his observations, he formulated his ‘Theory of atom’.