Ernest Rutherford: Difference between revisions
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On 7 March 1911, Rutherford presented his results publicly for the first time. An eyewitness has recalled : "I remember well the occasion on which the idea was first put forward. It was a meeting of the Manchester Literary and Philosophical Society to which all workers in the laboratory were invited. Rutherford's account of his theory, backed by Geiger with some new experimental evidence, created a profound impression." The definitive paper on the subject appeared in the May 1911 issue of Philosophical Magazine. Here Rutherford records a first decent estimate of the radius of a nucleus : about a hundred thousand times smaller than that of an atom. Thus if one imagines an atom blown up to the size of a football field, then the nucleus would be the size of a marble placed at the kick off point. Nuclei are not only heavy. They are also exceedingly small, even by atomic standards. Matter consists largely of emptiness.
Manchester in 1912 was the world's foremost center of experimental studies in radioactivity. The discovery of the atomic nucleus is in fact a by-product of such explorations. But at that time, the Rutherford model was still not taken seriously. There was no mention of it in any place. Rutherford's own reticence must have been an important contributing factor. He remained silent about his model during a major international conference (the first Solvay conference) held in the fall of 1911. In his 670 page book, completed a year later, only three pages are devoted to alpha-particle scattering.
Bohr later wrote :
<blockquote>
This effect -- the large angle scattering of alpha-particles -- though to all appearances insignificant, was disturbing to Rutherford, as he felt it difficult to reconcile it with the general idea of atomic structure then favoured by the physicsists.
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