Atomic Bomb

The "Little Boy"

The Atomic Bomb is defined as 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." An atomic explosion has a strength equal to that created by thousands of tons of TNT. or Trinitroluene.

The function of an atomic bomb is to provide enough mass of plutonium or uranium to reach what is called " critical mass," where nuclear reactions going on inside the material can make up for the neutrons leaving the material through its outside surface. The two elements of plutonium or uranium in a bomb are usually separated into parts in order for the critical mass not to be reached until the bomb is ready. Once that point has been reached, any kind of mechanism or chemical explosive will drive all of the separated uranium and plutonium together to reach that "critical mass." It is then that there are sufficient amounts of neutrons bouncing inside to create a chain reaction of fission; collisions between neutrons and the atoms of uranium and plutonium cause the atoms to split into pairs of nuclear fragments releasing energy and more neutrons. The newly released neutrons hit other atoms, continuing many more fission reactions until the "fissile" material is too exhausted or scattered and cannot continue. The intense explosion is a release of enormous amounts of energy in the form of heat and a massive shockwave. The damage occurred is almost unimaginable, with pressure waves, flash burns, high winds, and a deadly radiation in the form of gamma rays and neutrons. Living matter is destroyed, and soil and water are contaminated also.

It is important to note that atomic bombs were the first of any nuclear weapons to be tested and used. In the late 1930's, American and European physicists realized the power that could be created by the fission of uranium, having the potential to be an extremely powerful explosive weapon. Albert Einstein sent a letter of warning in 1939 to the U.S. president at the time, Franklin D. Roosevelt, describing his discovery and concern of its possibility of development in other countries. The U.S. government set up a top secret project, the Manhattan Project, to develop and test the first atomic bombs. The Manhattan Project was led by Army Brigadier General Leslie R. Groves, to conduct tests by working teams in different locations. Most of the work took place in Los Alamos, New Mexico, under the direction of J. Robert Oppenheimer, an American physicist. Their first test would be at Alamogordo, New Mexico, on July 16, 1945.

WWII presented the United States with an opportunity to use this new creation. On August 6, 1945, less than a month after its first testing, an atomic bomb nicknamed the "Little Boy" was dropped on the Japanese city of Hiroshima. "Little Boy" killed as many as 100,000 people that day. Following Hiroshima, a second bomb called "Fat Man" was dropped on Nagasaki, Japan, three days later on August 9^th. It killed about 40,000 more people. With these fatal destructions, Japan surrendered to the U.S. on August 14^th. Those were the only times since that any nuclear weapons had been used in a conflict between nations.

The "Fat Man"

Sites for further Information

   "A-Bomb WWW Museum"
    http://www.csi.ad.jp/ABOMB/index.html

    "Damages caused by atomic bombs"
    http://mothra.rerf.or.jp/ENG/A-bomb/History/Damages.html

"The City of Hiroshima"
http://www.city.hiroshima.jp/

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