The second clue was that the ratio m/e had a negative value. This allowed Thomson to conclude that the smallness of the electron's m/e ratio was due to either the smallness of m or the largeness of e (or a combination of the two). Thomson's result showed that the mass-to-charge ratio of hydrogen, as determined by electrolysis experiments, was 1,000 times larger than the same ratio for the electron. Thomson's data, however, provided two important clues. Thomson's experimental measurements gave a single number that represented only the ratio of the electron's mass divided by its charge, m/e thus Thomson could establish neither the electron's charge nor its mass separately. Thomson discovered "matter in a new state" and with this discovery it was clear, as Thomson wrote, "the subdivision of matter carried very much further."1 Thomson's new state of matter eventually became the electron, and with its discovery most physicists understood that the atom had inner parts. Thomson (1856-1940), who in 1884, at the age of twenty-eight, became Cavendish Professor of Experimental Physics at the University of Cambridge, following in the steps of James Clerk Maxwell (1831-1879) and Lord Rayleigh (1842-1919). One of those whose discoveries prepared the field for Bohr and others was J. The time of his birth was auspicious for a budding physicist: when Niels Bohr received his doctorate in 1911, the world of physics was pregnant with potential. The family home was a place where Professor Bohr and his university col leagues gathered and young Niels was exposed to the ideas that animated intellectual discussions during the concluding years of the nineteenth century. Niels had one older sister, Jenny, and one younger brother, Harald. Christian Bohr, his father, was a professor of physiology at the University of Copenhagen and his mother, Ellen Adler, came from a prominent Jewish family. Niels Henrik David Bohr was born in Copenhagen, Denmark on October 7, 1885. Bohr's recognition of the significance of Balmer's formula is a classic example of the prepared mind. When Balmer's formula came to Bohr's attention, however, he was already deeply engaged in an intellectual struggle to develop a model of the hydrogen atom that, among other things, explained its spectral behavior. Bohr did see Balmer's formula, he did make the statement quoted above, and he did proceed to develop his model of the hydrogen atom quickly. Unfortunately, neat logic must give way to the reality of events as they occurred. "As soon as I saw Balmer's formula, the whole thing was immediately clear to me." How logically neat it would be if Balmer's simple formula had, out of the blue, led Bohr directly to his model of the hydrogen atom. Bretislav Friedrich and Dudley Herschbach Scored a stunning success in accounting for major features of the observed spectrum of the hydrogen atom.
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