Rutherford performs the alpha particle scattering experiment. Alpha particles incident on a gold foil in a vaccum are scattered by a range of angles, due to the electrostatic repulsion between the positively charged alpha particles and positively charged gold nucleus. The experimental results obtained by Rutherford did not correspond to the theoretical predictions made by the plum pudding model. Therefore, the plum pudding model had to be replaced.The plum pudding model has the charge spread over a volume that was too high to display the experimentally observed results, so a new model was introduced (nuclear model) with the positive charge spread over a much smaller volume, inside a nucleus, as a way to increase the positive charge density. This also meant that much of the mass was concentrated inside a nucleus aswell. The theoretical predictions of the new model matched the experimental results, hence the nuclear model is the accepted model by the scientific community.