What did the results of the gold foil experiment demonstrate?
The gold foil experiment was conducted under the supervision of Ernest Rutherford at the University of Manchester in 1909 by Hans Geiger and Ernest Marsden. The popular theory of atomic structure at the time of Rutherford’s experiment was the “plum pudding model.” This theory held that the negatively charged electrons in an atom were floating in a sea of positive charge (the electrons playing the role of plums in a bowl of plum pudding). Rutherford’s gold foil experiment demonstrated that almost all of the mass of an atom is in a tiny volume in the center of the atom which Rutherford called the nucleus. This positively charged mass was responsible for deflecting alpha particles propelled through the gold foil. Rutherford’s “nuclear model” of the atom replaced the plum pudding model in 1911.