What is an Atomic Bomb?
• Powerful explosive nuclear weapon fueled
by the splitting, or fission, of the nuclei
of specific isotopes of uranium or
plutonium in a chain reaction
• What is fission?
– The act or process of splitting into
Who Created the Atomic Bomb
and When was it Created?
• Named the Manhattan Project
• The leader of the Manhattan Project was U.S.
Army Brigadier General Leslie R. Groves; His
team worked under the direction of American
physicist J. Robert Oppenheimer
• Development of the atomic bomb began in 1942
When was the First Bomb
• The first atomic explosion was conducted, as a
test, at Alamogordo, New Mexico, on July 16,
• August 6, 1945 the US drops first atomic bomb on
Hiroshima, Japan ("Little Boy")
• August 9, US drops second atomic bomb on the
city of Nagasaki ("Fat Man")
Statistics of the Bomb
• 60,000 to 70,000 people were killed by the
• 40,000 by the bomb dropped on Nagasaki
Blue= Death Toll
Why was the Atomic Bomb Dropped?
• To save Americans soldiers lives
– Options were to invade Japan or drop atomic
• Invasion of Japan had casualty numbers of
500,000 to 1 million soldiers killed/wounded
– Fierce house-to-house combat
• Atomic bomb losses projected at American
– Decision made by President Harry S. Truman
Negative side to to the Atomic
Bomb (people’s opinions)
• People thought the bomb was not dropped on
European enemies but on people of a nonwhite
• “ A few scholars, notably Gar Alperovitz, have
further charged that the atomic holocaust at
Hiroshima and Nagasaki was not the final shot of
World War II but the first salvo in the cold war.”
Who Delivered the Atomic Bomb?
• The USS Indianapolis
– Delivered parts of “Little Boy” on July 30,
1945 in a Top Secret mission
• Dropped 2 weeks later
– Torpedoed by Japanese submarine
• 300 killed on impact
• 900 sailors went into the Pacific for over 5
• 321 survived to be rescued
–4 later died in the hospital
• Microsoft, Encarta, Microsoft Corporation, 2003
• Stanton, Doug. In Harm’s Way. Henry Holt and Company, New York,
• Bailey, Thomas A., and David M. Kennedy. The American Pageant.
10th ed. Lexington, MA: D.C. Health and Company, 1994.