The Manhattan Project, one of the best-kept secrets of World War II, had one main goal — to create an atomic bomb. Not only was the project a great scientific achievment, it was also a project that resulted in unimaginable destruction. Over 600,000 Americans worked on the Manhattan Project. However, many never knew what the outcome was going to be.
The project began in 1942 when a group of scientists working for Enrico Fermi at the University of Chicago, achieved a controlled nuclear reaction. General Leslie Groves organized the Manhattan Project and built atomic reactors in Tennessee and Washington in order to produce the rare form of uranium, uranium 235 as well as the rare radioactive element plutonium. (Go to the Nuclear Fission page for more information on Uranium 235).
In Los Alamos, New Mexico an elite group of scientists headed by J. Robert Oppenheimer (Click for biography) were given the task of actually building the bombs. Such an elite group was selected by General Groves himself. General Groves pressured the scientists at Los Alamos in order to centralize focus in creating the atmoic bombs and avoid distractions.
Although General Groves picked Dr. Oppenheimer to lead the project at Los Alamos, he became hesitant in Dr. Oppenheimer's political situation. From phone taps, General Groves found out that Dr. Oppenheimer had an affair with a communist lady. Eventually Dr. Oppenheimer left his affair and continued with his work on the Manhattan Project and was pushed to the limits in order to meet deadlines.
On July 16, 1945, the first atomic bomb was tested in a desert near Alamogordo, New Mexico. The bomb was called "Trinity" and was an implosion-design plutonium bomb. Nobody knew the amount of power that would be produced from the bomb. Even before the test some scientists feared the explosion would cause the end of the world. However, this was found impossible before testing after the scientists calculated it to be impossible. Some also feared the bomb would not work and the chain reaction inside the bomb would fail.
The explosion was the same as the amount of power of 20 kilotons of TNT. Its tremendous power was used by President Truman as leverage in his negotiations with the Soviet Union at the Potsdam Conference, however such information did not come as a suprise to Stalin. The Soviet Union knew about such an enterprise before actual results were made.
Although Trinity was a success, the use of the other two bombs was not clear. Even before the test of the atomic bomb, scientists who even worked on the project started a petition, which was led by Leo Szilard, which stated that dropping such a destructive weapon on Japan was immoral especially without fair warning. One solution was to demonstrate the power of the atomic bomb to Japanese leaders in hopes of convincing them to surrender.
Eventually many scientists agreed with dropping the atomic bomb because enough Americans have died in the war and if United States invaded Japan in order to end the war, many more would die. Even then there were still a handful of scientists strongly against the decision to drop the bombs.
There were other factors to reasoning out the use of the bombs. First, the Manhattan Project was very costly and if the bombs were not used all the money put into the project would seem wasted. So the use would justify the money spent on the project. The second factor delt with tensions building between Soviet Union and the United States. If the United States used the bombs then it would show the Soviets the military advantage that the United States has.
On July 25, 1945, President Truman ordered the final plans for dropping the atomic bombs on Japan. Warnings were sent out to Japan and tried forcing Japan to surrender. Japan refused to surrender and so the United States acted in making final preparations to drop the bombs.
Little Boy was the result of nuclear fissioning of enriched uranium. It was dropped over Hiroshima on August 6, 1945 and became the first atomic bomb ever used as an offensive weapon. It was released by a B-29 bomber named Enola Gay. Full testing of gun type design , which was used in Little Boy, never really occured. Scientists believed such a design was almost guaranteed to work. Another reason for limited testing before the drop of Little Boy was because Little Boy used uranium 235. uranium 235 is a rare isotope of uranium and very little of it exists. After the bombing, the United States believed Japan would surrender. Surrender never occured and the United States acted by using the third atomic bomb created from the Manhattan Project.
On August 9, 1945, Fat Man was dropped over Nagasaki and flattened much of the city. Its power was estimated to be greater than that of Little Boy. Fat Man had a similar design to Trinity and used plutonium as its fuel. After seeing the destruction of of his people, Japanese Emperor Hirohito surrendered.