'Little Boy'

The second bomb created was codenamed the ‘Little Boy’ (Bracchini 1). It was uranium powered fission bomb (Bracchini 1). Uranium was a very hard element to obtain that most of the uranium used for the bomb had to be created in factories. Therefore, only one of these bombs could be created (Bracchini 1). In addition, the Little Boy had a simple design which used a simple ‘gun-type’ detonator to start the nuclear reaction (Bracchini 1). Therefore, theoretically, it was such a simple bomb design so it should work without the need for an experimental copy. The Little Boy was detonated over Hiroshima and caused hundreds of thousands of deaths throughout many years (Bellis 1).

'Fat Man'

The third atomic bomb was codenamed ‘Fat Man’(Bracchini 1). It was basically a final copy of the earlier plutonium test bomb, the Gadget. Both used plutonium, which was much easier to stockpile then uranium, as a nuclear fuel source and they had similar implosion cores. The only difference being that the Fat Man had a much larger yeild, which was around 25 kilotons or 25,000 tons of TNT. It was detonated over Nagasaki on August 9, 1945. An estimated 90,000 people were killed, directly and indirectly, by the blast. It was the third and last nuclear bomb to ever be used against another country (Bellis 1).

SOURCES:

Bellis, Mary. “The History of the Atomic Bomb.” About (2000): 1. 7 July 2005 <http://inventors.about.com/library/weekly/aa050300a.htm>.

Bracchini, Miguel. “Atomic Bomb Design.” The Manhattan Project (1997): 1. 7 July 2005 <http://www.me.utexas.edu/~uer/manhattan/bomb-design.html>.