The Atomic Bomb United States believed Hitler was

The Atomic Bomb

• United States believed Hitler was developing an Atomic bomb

Manhattan Project • U. S. program to develop an Atomic Weapon • Chief Scientist Robert P. Oppenheimer • President Truman didn’t learn about program until he became President • 1 st Atomic bomb was tested on July 16 th 1945

The Manhattan Project cont… • U. S. feared that an invasion of Japan would result in 200, 000 American casualties – and perhaps 1 -2 million Japanese casualties • U. S. considers using an “Atomic Bomb” to end the war quickly • Bomb had been developed as part of the “Manhattan Project” – beginning in 1942

How to use the Atomic Bomb 1. Drop a bomb on and island in the Pacific to scare the Japanese into surrendering 2. Drop the Atomic bomb on Japanese cities

United States Warns Japan • Truman told Japan they could expect a “Rain of ruin from the air” No response from Japan

Fat Man & Little Boy

Targets • Hiroshima: 365, 000 People • Bombed dropped on August 6 th , 1945 at 8: 16 am • Enola Gay

Atomic Cloud Over Hiroshima

Hiroshima • • • Ground temp: 7, 000 degrees Winds: 980 mph Buildings destroyed: 62, 000 Killed immediately: 70, 000 Dead by end of 1945: 140, 000 Area of total vaporization from the atomic bomb blast measured one half mile in diameter

Before and After

Nagasaki • 200, 000 residents • Dropped on August 9 th, 1945

Nagasaki • 40, 000 died on day of the attack

Use the Bomb • Battle of Okinawa showed how determined Japan was to continue fighting • Japanese had strong personal honor; many followed Samurai Code • Invasion would mean 500, 000 to 1, 000 U. S. Deaths and maybe 2 – 4 million Japanese Not Use the Bomb • Intentionally targeting civilians was considered a war crime • 110, 000 civilians killed in the two bombings – 200, 000 dead when Radiation poisoning deaths are added • Truman was ‘out of the loop’ as Vice President – didn’t know destructiveness of bomb?

• Japan surrenders on September 2, 1945 • Long term effects of radiation caused cancer