The Manhattan Project Essay, Research Paper

Atomic bombs were the first nuclear weapons to be developed, tested, and used. In the late 1930s physicists in Europe and the United States realized that the fission of uranium could be used to create an extremely powerful explosive weapon. In August 1939, German-American physicist Albert Einstein sent a letter to U.S. president Franklin D. Roosevelt that described this discovery and warned of its potential development by other nations. The U.S. government established the top secret Manhattan Project in 1942 to develop an atomic device. Canada was asked, by Britain, to help in the secret scientific project. The British wanted to create a laboratory out of reach of the Luftwaffe and close to the United States. The Laboratory was built in Montreal in 1943, but by then it was too late to make a difference in the atomic weapons program, the United States had already completed their own laboratory. However, uranium was needed for the United State s bomb.

The key ingredient in the creation of the atomic bomb is Uranium-235. Uranium-235 is a pure, highly unstable substance which can only be obtained from natural uranium. Because the concentration of the Uranium-235 in natural uranium is so small, a very large amount of the substance is required. A uranium mine at Great Bear Lake, in Northwest Territories was secretly bought by the Canadian government to supply the uranium for the United State s Manhattan Project. Canada also had the only uranium refinery outside Nazi-occupied Europe. It was at Prot Hope, Ontario. The leader of the Manhattan Project was U.S. Army Brigadier General Leslie R. Groves. His team, working in several locations but in large part at Los Alamos, New Mexico, under the direction of American physicist J. Robert Oppenheimer, designed and built the first atomic bombs.

The first atomic explosion was conducted, as a test, at Alamogordo, New Mexico, on July 16, 1945. The energy released from this explosion was equivalent to that released by the detonation of 20,000 tons of TNT. Near the end of World War II, on August 6, 1945, the United States dropped the first atomic bomb on the Japanese city of Hiroshima. It followed with a second bomb against the city of Nagasaki on August 9. According U.S. estimate, 60,000 to 70,000 people were killed by the Hiroshima device, called “Little Boy,” and about 40,000 by a bomb dropped on Nagasaki, called “Fat Man.” Japan agreed to U.S. terms of surrender on August 14th. These are the only times that a nuclear weapon has been used in a conflict between nations.

Hiroshima was the city on the southwestern Japanese island, Honsh . The city was founded in 1594 on six islands in the +ta River delta. Hiroshima grew rapidly as a castle town and commercial city, and after 1868 it was developed as a military center. On August 6, 1945, during World War II (1939-1945), the first atomic bomb to be used against an enemy position was dropped on the city by the United States Army Air Forces. According to U.S. estimates 60,000 to 70,000 people were killed or missing as a result of the bomb and many more were made homeless. (In 1940 the population of Hiroshima had been 343,698.) The blast also destroyed more than 10 sq km (4 sq mi) of the city, completely destroying 68 percent of Hiroshima’s buildings; another 24 percent were damaged. Every August 6 since 1947, thousands participate in interfaith services in the Peace Memorial Park built on the site where the bomb exploded. In 1949 the Japanese dedicated Hiroshima as an international shrine of peace.

After the war, the city was largely rebuilt, and commercial activities were resumed. Machinery, automobiles, food processing, and the brewing of sake are the main industries. The surrounding area, although mountainous, has fertile valleys where silk, rice, and wheat are produced. The population in 1990 was 1,085,705.

Nagasaki was another city in Japan, on the western Ky sh Island. Nagasaki Bay is about 5 km (about 3 mi) long and sheltered on all sides, is one of the best natural harbors of Japan. The city has important coal-mining and fishing industries, shipyards and steelworks, and plants manufacturing electrical equipment. It is the site of Nagasaki University (1949). On August 9, 1945, during World War II, three days after Hiroshima was destroyed, a U.S. Army Air Force plane released an atomic bomb (Fat Man) on Nagasaki. About one-third of the city was destroyed and according to U.S. estimates 40,000 people were killed or missing. A memorial now marks the location over which the bomb exploded. The population in 1990 was 444,599.

The atomic bomb is a powerful explosive nuclear weapon fueled by the splitting, or fission, of the nuclei of specific isotopes of uranium or plutonium in a chain reaction. The strength of the explosion created by an atomic bomb is on the order of the strength of the explosion that would be created by thousands of tons of TNT.

An atomic bomb must provide enough mass of plutonium or uranium to reach critical mass, the mass at which the nuclear reactions going on inside the material can make up for the neutrons leaving the material through its outside surface. Usually the plutonium or uranium in a bomb is separated into parts so that critical mass is not reached until the bomb is set to explode. At that point, a set of chemical explosives or some other mechanism drives all the different pieces of uranium or plutonium together to produce a critical mass. After this occurs, there are enough neutrons bouncing around in the material to create a chain reaction of fissions. In the fission reactions, collisions between neutrons and uranium or plutonium atoms cause the atoms to split into pairs of nuclear fragments, releasing energy and more neutrons. Once the reactions begin, the neutrons released by each reaction hit other atoms and create more fission reactions until all the fissile material is exhausted or scattered.

This process of fission releases enormous energy in the form of extreme heat and a massive shock wave; this is the intense explosion. In addition to its nearly unimaginable destructive force, consisting of pressure waves, flash burns, and high winds, a nuclear explosion also produces deadly radiation in the form of gamma rays and neutrons. The radiation destroys living matter and contaminates soil and water.

Fusion bombs, also called hydrogen or thermonuclear bombs, were developed and tested in the early 1950s, but these have never been used in warfare. A thermonuclear device depends on a fission reaction to produce extreme heat that causes hydrogen isotopes of deuterium and tritium to come together, or fuse, but the main energy source for thermonuclear devices comes from the fusion reaction, not the triggering fission reaction.

Several nations have exploded nuclear devices in tests in the atmosphere, under the earth, and under the sea. Only the United States, Russia, Great Britain, France, and the People s Republic of China admit to possessing nuclear weapons. Other nations, however, including Israel and South Africa, are thought to have them as well, or to have the capability to assemble them quickly. All in all, the mass weapons of destruction spread among the globe have enough potential power to destroy every last city on earth. Nuclear weapons, though, aren t all bad. They have a very important use, for example, in the defense of the earth against meteors and asteroids. People will always have an urge to make a bigger and more powerful weapon But the truth is they don t get much bigger than what we have now!