jan 1, 1909 - Ernest Rutherford Gold Leaf Experiment, 1909-1911

Description:

J.J.'s Former student Rutherford tested the Plum Pudding model in 1913. When he tested it he found that the alpha particles he used mostly reflected on the gold foil, (he used foils such as aluminum and lead too) but there were some instances where they reflected back. In the Plum Pudding model this shouldn't have happened. So Rutherford hypothesized that an atom had a positively charged center which held most of its mass, he called this the nucleus.