Rutherford Gold Foil Experiment - Backstage: Science

A detector that would flash when hit by an alpha particle. The Unexpected Result

Positively charged particles emitted from a radioactive source (radium).

To look inside the atom, Rutherford needed to fire something at it. He used:

In 1911, Ernest Rutherford and his team (Hans Geiger and Ernest Marsden) conducted the "Gold Foil" experiment, which Backstage Science describes as essentially the .

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While most did pass through, Rutherford was shocked to find that:

Chosen because gold is incredibly malleable and can be beaten into a sheet only about 1,000 atoms thick.

At the time, scientists believed in the , where an atom was a blob of positive charge with electrons scattered inside like fruit in a pudding. If this were true, the heavy alpha particles should have whizzed straight through the "soft" atoms.