Discovery of Radioactivity 1962 Educational Curie Rotegen, 1962,

“An historical survey of progressive developments leading to our present knowledge of radioactivity, this is the story of Wilhelm Roentgen and his discovery in 1895 that certain crystals become fluorescent when they are subjected to cathode tube rays. It includes Henri Becquerel’s discovery that uranium salts give off invisible rays, Marie Curie’s isolation of polonium and radium, and the work of Julius Elster and Hans Geitel, who measured the rays of an electroscope. Analyses by Ernest Rutherford revealed alpha, beta, and gamma rays. Further studies showed how a substance decays at a particular rate and that radioactive substances contain a mixture of different atomic elements. The discovery of radioactivity led to a new conception of the structure of the atom and of matter.”