Attack on the Atom

Radio Record, Volume V, Issue 51, 1 July 1932, Page 31

Attack on the Atom

eel Latest Research Work Se emnetiemnaaael HB annual exhibition of the British Institute of Radiology was opened in London on December 3 by Lord Rutherford, who not only gaye one of extraordinarily’ simple and yet illuminating expositions of the history of atomic physics, but added an announcement of the results of his latest researches, At the Cavendish Laboratory a ¢oordinated attack has been made on the problem of the structure of the nucleus of the atom. The nature of the nucleus may be deduced from the rays it emits when it disintegrates, but the rays are 80 complicated that progress has been slow in the study of how they are produced. Lord Rutherford is now fairly certain that the penetrating rays from radium, which resemble X-rays, but surpass them in power of penetration, are due to the vibration of the nuclei of helium atoms within the nucleus of the radium atom. They appear not to ve due the vibrations of the ultimate particles, the protons and the electrons, but to groups of these bound together as in the nuclens of the hélium atom, and the mechanism is of the type suggested by the young Russian physicist, Gamow. Lord Rutherford recalled his early days in the Cavendish Laboratory after the X-rays had just been discovered in Germany. The application of them made the discovery of radio-activity and of the electron much simpler. Indeed the discovery of the X-rays »y , Rontgen in 1895 really marks the division between the old physics and the new. A. What is Radiation? | DURING the exhibition, Sir James Jeans, one of England’s most noted scientists, delivered a lecture on "What is Radiation?" _ . The chief characteristics of radiation are that it travels and carries energy. According to our idea of familiar things, such as stones. atid water, energy is carried by them as by particles and waves. When energy is carried by stones or particles it is assumed that they fly through empty space. When the energy is carried by waves just the contrary happens, for one cannot eonceive waves as travelling through emptiness. Newton first tried to explain light by particles, but the explanation broke down. Then the idea of light as wayes was developed, and was so successful that in the nineteenth century physicists, except one or two profound ones like Maxwell, were quite certain light was; wave-like, and that a substance existed to transmit it, the ether. But as the knowledge of light became deeper is was found to have unexpected particle-like properties. The particlelike properties were more evident m light of short wavelength, such as Xrays. By 1905, Einsten had developed 2 theory which conceived of light xs bundles of entities called photons. These have weight, but no electric ~ eharge. They can be conceived as a /¢orm of a fundamental structural unit of nature which has two alternative forms, the electron anu the proton. As a rule protons and electri ©: move much less quickly than light, because they have to carry charges of electricity about with them. Ali of the three fun

damental units ara 4 combination, as it were, of wave and particle characteristics, sometimes showing one property and sometimes another. Photous have very little weight; in fact, the electric light companies have to supply so little to light Our houses that they can charge us £17,000,000 an ounce for photons. This expense of photons éxplains in the last analysis why the transmutation of metals into gold would be uneconomic if we could do it. The cost per Gunce would be of that order.