Atomic bomb theory

Niels Bohr was a physicist, not a chemist. I devote a chapter to his life because he was the scientist who explained why Mendeleev s periodic table had the properties it did. Widely known as a soccer player in his youth, Bohr became the most influential physicist of the first half of the twentieth century. His life, too, was touched by political events. A Jew living in occupied Denmark, Bohr had to flee the country to avoid arrest by the Nazis. In 1939 Bohr discovered a theory that explained nuclear fission, and suggested that uranium 235 could be used to make a bomb. Though he played only a minor role in the American atomic bomb project, Bohr was the first to ponder the political implications of the bomb. 

But the distance between the laboratory and the marketplace is often long. Space engineers didn t invent rockets one day and send men to the moon the next. Some twenty years elapsed between the discovery of the double-helix structure of DNA and the first transplantation of a gene from one organism to another. The atomic bomb came forty years after Albert Einstein gave us the theory behind it and his formula that linked energy and matter E = me2. As Donna Fitzpatrick of the Department of Energy recalls ... 

With the discovery of the neutron as a fundamental particle, many paradoxes of physics and chemistry were finally resolved, and new areas of research evolved. Prior to the discovery of the neutron as a fundamental particle, scientists generally believed that the nucleus was comprised of protons and nuclear electrons. However, one could not explain, for example, the spin of nuclei with that model. Now, at last, theory could predict the properties of the nucleus quite well. Also, since neutrons are not repelled by the charge on the atomic nucleus, they interact easily with nnclei. Nen-tron scattering enables the determination of crystal stmctnres by probing the positions of nuclei in a sample. Neutrons can also catalyze fission reactions, for example, the fission of uranium nuclei that led to the creation of nuclear power plants and the atomic bomb. 

There is an interesting story told about the development of this equation in the late 1930 s. It is said that Brunauer and Emmett were having difficulty developing the theory and arranged a meeting over lunch with Teller, who later became famous because of his involvement in Atomic bombs and Hydrt n bomb theory. It is said that Teller worked out the basic equation for gas adsorption on a table cloth were the lunch was held and that Brunauer and Emmett had to buy the table doth to take it back to the laboratory [5]. 

Atomic science was in its infancy as well. In his book. Wells predicted that the splitting of the atom, a chemical reaction known as fission, would produce an enormous amount of explosive energy— enough energy to level a city. But when Wells had published the book, the splitting of the atom had occurred in theory only. The first actual fission reaction would be created in a laboratory twenty-four years afier the publication of Wells s book. The first experiment in which scientists controlled the fission reaction—a vital step in the creation of the atomic bomb— would not occur until four years after that. 

The results of the Windscale fire have important implications in the general theory of the effects of nuclear accidents. Both Britain and the US have used polonium in the atomic bombs they have exploded. Even if each bomb contained only 500 Ci, less than one tenth of a gram, the hundreds of tests could have contributed significantly to world leukaemia and cancer levels. Eurther information on the... 

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