In 1913, Hans Geiger and Ernest Marsden performed a scientific experiment by which they proved the existence of the atomic nucleus by measuring how a metal foil scatters a beam of alpha particles. This is a computer-generated model of the apparatus they used to measure how the scattering varied with the angle of incidence. It is based on this illustration provided in Geiger and Marsden's original 1913 paper, The Laws of Deflexion of a Particles through Large Angles.