In 1897, a British physicist named J. J. Thomson discovered electrons through his cathode ray experiment. Thomson made the cathode ray by firing electrical currents through glass pipes filled with low-density gas. Thomson measured the ratio as always the same, regardless of what elemental gas was in the
pipe. These results indicated that the current inside the cathode ray tube was made of tiny particles that carried a negative charge. He named these particles electrons. Since the mass to charge ratio was the same no mater what gas he used inside the glass tube. Thomson reasoned that electrons must be common to all atoms, and that all electrons must be the same.
Ernest Rutherford was born in New Zealand in 1871 as one of 12 children. It was Rutherford who first "split" an atom and who discovered the atomic "nucleus", a name that he invented. For this he is regarded as the greatest experimental physicist of his time. Rutherford was one of the first and most important researchers in nuclear physics. Soon after the discovery of radioactivity in 1986 by the French physicist Antoine Henri Becquerel, Rutherford discovered the three different types of radiation. By covering his Uranium with thin foils of aluminum, gradually increasing the number of foils. For the first three layers of foil the radiation escaping from the uranium decreased progressively, suggesting an ordinary law of absorption. More thickness of aluminum, however, had little further effect in reducing the radiation at first, but eventually the intensity of the radiation began to diminish again as even more foils were added. These experiments showed that there were at least two distinct types of radiation- one that is very readily absorbed, which he called t...