utherford said that this was the most surprising result he had known. He said that this discovery of the alpha particles actually bouncing off the gold was as surprising to him as firing a fifteen inch shell at a piece of tissue paper and having it bounce back and hit you. From this statement we can see how immersed Rutherford actually was in his studies. By this experiment it seemed clear to Rutherford that the alpha particle occasionally encountered such an intense field in the atom that it was turned back in its path as the result of a collision. When considering the mass and energy of an alpha particle this was an astonishing observation. Rutherford said that in order to produce such a large deflection of the alpha particle, the atom must contain a massive charged center of very minute dimensions. From this arose the concept of the well known "nucleus" (a name which Rutherford coined), where the atom consists of a minute positively charged nucleus containing most of the mass of an atom, surrounded at relatively great distances by electrons. He also discovered that the alpha particle was repelled according to the ordinary laws of electricity so that it should travel in a hyperbola. From this he discovered the law of scattering, that is to say the number of particles that should be found at any angle of deflection. Rutherford was confident that we would get more information from scattering about the nature of the atom than any other method. Rutherford became very excited about an idea that Darwin had given him about the interesting results that might occur when an alpha particle met a nucleus lighter than itself, such as the nucleus of a hydrogen atom. Rutherford went to work right away. In 1919 Rutherford performed a pioneer experiment in nuclear physics when he bombarded nitrogen gas with alpha particles and obtained atoms of an oxygen isotope and protons. This process of changing nitrogen into oxygen was the first artificially indu...
