Fermi's (non) Discovery of Nuclear Fission
Not many people know that the famous physicist and Nobel Laureate Enrico Fermi was the first person to successfully split the uranium atom. He had achieved this feat in 1934 (four years before Lise Meitner, Otto Hahn and Fritz Strassmann published their paper on "nuclear fission" in 1938), but had failed to recognise the significance of his findings.
Fermi was working on an experiment in the University of Rome, which involved bombardment of a tiny amount of uranium with a neutron gun (a half inch long glass tube from which beryllium neutron were ejected, knocked out by powerful nuclear "bullets" from radium). As a result, the uranium atom was split into two lighter elements, accompanied by a release of a vast quantity of atomic energy. Fermi, and his four associates, saw the nuclear products, but could not see the nuclear reaction because a thin aluminium foil was placed around the crucible to prevent the short-range radiation from passing through.
Fermi was puzzled by the results. It was inconceivable for him to recognise that he had split the atom. After all, such great physicists as Einstein, Planck, Rutherford, and Bohr had expressed doubts that atom can ever be broken. Nevertheless, he published his results, never interpreting them as fission. What is remarkable is that for the next nearly five years, Fermi's experiment was replicated by scientists around the world, with similar results, but no one considered the possibility of nuclear fission.
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