The Manhattan Project

The Manhattan Project was the code name of the U.S.’s attempt to construct an atomic bomb during


World War II.   It was named after the Manhattan Engineer District of the U.S. Army Corps of Engineers,


because a lot of it’s earlier research was done in New York City.   An atomic bomb is a weapon that uses


the energy from a nuclear reaction called Fission for its destruction.


The idea that mass could be changed into energy was predicted by Albert Einstein in the earlier


part of the 1900’s.   John D. Cockcroft and Ernest Walton confirmed this by experiments in 1932.   Then in


1938, nuclear fission was discovered by German scientists, and it was feared by many of the U.S.


scientists, that Hitler would try to build a fission bomb.   Three Hungarian-born physicists, Leo Szilard,


Eugene Wigner, and Edward Teller asked Albert Einstein to send a letter to Franklin Roosevelt.


Compelled by the letter in late 1939, Roosevelt ordered an effort to obtain an atomic weapon before


Germany.


At first, this program was led by Vannevar Bush, head of the National Defense Research committee


and the Office of Scientific Research and Development.   Then it came under control of Leslie Groves of


the Army Corps of Engineers.   Groves quickly bought a site in Oak Ridge, Tennessee, as a place for


processing the Uranium-235   from the more common Uranium-238.   Uranium-235 is used because it is


fissionable, it releases many neutrons, and does not capture many.   However, 99.3% of uranium in nature


is the U-238 isotope, and only .7% is the lighter, more “fissionable” isotope U-235.   Next, he gathered


and combined research from many East Coast universities under direction of Arthur Compton, at the


University of Chicago.   He appointed theoretical physicist, J. Robert Oppenheimer as the director of the


weapons laboratory, which was built on an...