In 1911, Ernest Rutherford carried out an experiment to probe the atom. He directed a narrow beam of α-particles all with the same kinetic energy at a thin gold foil only a few atoms thick. The alpha particles were detected by a detector which could be moved around at a fixed distance from where the alpha particle beam hit the metal foil. A microscope was used to observe the point of light emitted by the α-particles hitting a fluorescent screen.The results were that most of the alpha particles passed straight through the foil and a small percentage (about 1 in 10,000) were deflected through angles of more than 90°.