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World War II
The Manhattan Project



The Manhattan Project
Reading Level
     edHelper's suggested reading level:   grades 8 to 10
     Flesch-Kincaid grade level:   7.93

Vocabulary
     challenging words:    calutrons, centrifuge, cryptic, diffusion, fallout, gaseous, plutonium, say-continue, self-sustaining, radioactive, electromagnetic, reactive, uranium, fission, scrap, reactor
     content words:    World War II, Albert Einstein, President Roosevelt, General Leslie R., Army Corps, Substitute Materials, New York, Manhattan Project, Oak Ridge, Los Alamos


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The Manhattan Project
By Mary Lynn Bushong
  

1     One of the big fears at the start of World War II was that the Nazis were working to develop an atomic bomb. Albert Einstein sent a letter to President Roosevelt encouraging him to fund research into nuclear fission for weapons to stop the Nazis.
 
2     In September 1942, General Leslie R. Groves of the Army Corps of Engineers was chosen to head up the research project. However, before bomb designs could even be considered, much more had to be learned. The project's original name was the cryptic "Development of Substitute Materials." Groves didn't care for that name, and he chose another one. The Army Corps of Engineers had a habit of naming projects after its headquarter's city. In this case, it was in New York, and the name became the Manhattan Project.
 
3     On September 19, 1942, 32,000 acres in Oak Ridge, Tennessee were purchased to become a secret laboratory and production site. Then on November 16, property at Los Alamos became another site.
 
4     One of the first experiments carried out for the Manhattan Project was to discover if a self-sustaining nuclear chain reaction could be produced. The successful experiment on December 2, 1942 was carried out by an Italian scientist named Enrico Fermi. He carried out the experiment under the bleachers of Stagg field at the University of Chicago.
 
5     In February 1943, the new electromagnetic separation facility to enrich uranium was begun in Oak Ridge. The calutrons which did the work were monitored by WAACs. Before uranium could be enriched, however, the correct type had to be found. It was decided that U (uranium) -235 was right for the job. It was unstable and could sustain a chain reaction.
 
6     A second element, P (plutonium) -239, was another reactive substance that had potential. The problem was, both of these elements were rare, and it would be difficult to find as much as was needed for the job.
 
7     There are many deposits of uranium in the world, but only 1% of it is U-235. The rest is useless for making bombs. Separating the isotopes was tried in different ways. One was to use magnetic separation. The second was through a process called gaseous diffusion. It turned out to be the most efficient and effective method of producing U-235. The third way was to use a centrifuge, but it was abandoned before testing.
 
8     A third testing site was acquired in Hanford, Washington. The small reactor was too dangerous to continue using in Chicago, and the Oak Ridge site was too close to Knoxville, in case something happened to the planned large reactor. The possible fuels needed to be tested and the bombs themselves designed. The Hanford site was judged to be remote enough not to be a problem.
 
9     Over all, the project produced 3 atomic bombs. The first was "Gadget," a plutonium bomb that would be exploded at the Trinity test site. The second was "Little Boy," a uranium bomb. The last was "Fat Man," another plutonium bomb.

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