Geiger–Marsden experiment
The Geiger–Marsden experiment (also called the Gold foil experiment or the Rutherford experiment) was a scientific experiment done by Hans Geiger and Ernest Marsden in 1909. They were instructed by Ernest Rutherford, and the experiment happened at the Physical Laboratories of the University of Manchester.  The results of the experiment were surprising. They showed scientists that the atomic nucleus exists. This disproved the plum pudding model of the atom, and led to the Rutherford atomic model (also called the planetary model).