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• 1st Atomic bomb was tested on July 16th

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 6th , 1945 at

8:16am• Enola Gay

Atomic Cloud Over Hiroshima

Hiroshima

• Ground temp: 7,000 degrees • Winds: 980mph• 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 9th, 1945

Nagasaki

• 40,000 died on day of the attack

Use the Bomb Not 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 1,000,000 U.S. Deaths and maybe 2 – 4 million Japanese

• 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