The Atomic Bombs and the End of WWII

The Atomic Bombs and the End of WWII

U-235 atomic bomb / Little Boy

U-235 bomb was a fission bomb. A mass of uranium 235 is fired into another mass of U-235 to create fission.

Little Boy fission reaction which releases a burst of neutrons in a sustained reaction.

Fat Man fusion atomic bomb

In the Fat Man fusion bomb, an explosion is used to compress a small sphere of plutonium which creates a nuclear reaction.

Of natural uranium, only.7% is uranium 235 which can be used for atomic bombs. So, it takes a large quantity of uranium to produce the U-235 needed for fission. Uranium must be enriched to 90% purity to be weapons grade. In 1941, the U.S. obtained 941 pounds of uranium from the Belgian Congo. After the U 235 component was separated, it produced enough to make 4 bombs. Uranium is a silvery white metal. This is highly enriched uranium from a nuclear facility in Oak Ridge, Tennessee.

July 16, 1945 First successful testing of the atomic bomb at Alamagordo, New Mexico.

J. Robert Oppenheimer Was the leader of the Manhattan Project, the organization designed to build an atomic bomb. Upon completion of the task, Oppenheimer referred to the creation of such awesome power as, a sin!

**Colonel Paul Tibbits, Jr. (second from left) was the pilot of the Enola Gay (B-29) which dropped the atomic bomb on Hiroshima.

The USS Indianapolis delivered the key parts of the two atomic bombs to Tinian Island in the Marianas on July 26, 1945. She then continued on a route toward the Phillipines. On July 30, 1945, she was torpedoed by the Japanese I-58 submarine. Of 1196 crew members, 300 drowned with the ship. Of the remaining 900, only 316 survived. They were spotted by accident, four days later. Almost 600 men died of dehydration, heat, or shark attacks!

Reenactment of the repeated shark attacks the 900 sailors from the **USS Indianapolis were subjected to over a four day period in the Phillipine Sea, in June of 1945. 600 of 900 men in the ocean died!!

President Franklin Delano Roosevelt died of a cerebral aneurism in April of 1945. There was little evidence of his attitude toward the use of the atomic bomb.

**Vice President Harry S. Truman became president in April of 1945, after President Roosevelt s sudden death. Truman would have to make the decision whether or not to drop the atomic bombs. He had previously been a Senator from the state of Missouri.

Dr. Leo Sziliard of the Manhattan Project, argued that the U.S. should **demonstrate an explosion of the atomic bomb on a remote island in the Pacific.

Potsdam Conference (July 15 July 31, 1945) - - Truman discussed the bomb with British Prime Minister Winston Churchill and his replacement, Prime Minister Clement Attlee. Both thought we should use the bomb. Truman told Josef Stalin (Soviet Union) that we had an enormously powerful bomb and Stalin replied, Oh, that s nice.

Saving Lives by Using the Bomb Non-combatants were dying throughout Asia at the rate of 200,000 per month. The complete naval blockade of Japan would have resulted in hundreds of thousands of deaths due to malnutrition, dehydration, and famine. The atomic bomb saved thousands of American soldiers lives!

The Atomic Bomb at Hiroshima August 6, 1945

Kokura

The Mushroom Cloud 8:15 AM, Little Boy was dropped over the center of Hiroshima. It exploded about 2,000 ft. above the city and had a blast equal to 13 kilotons of TNT. Due to radiation, approximately 152,437 additional people died.

Hiroshima Before The Atomic Bomb

Hiroshima After The Atomic Bomb

Japanese View of Unconditional Surrender Emperor Hirohito was totally against unconditional surrender. Americans viewed Hirohito as a symbol of military aggression. Unconditional surrender destruction of divine monarchy.

Major Charles W. Sweeney and the crew of the Bockscar dropped the second atomic bomb on Nagasaki, on August 9, 1945.

The Japanese city of Kokura {map at left} was the primary target for the second atomic bomb. It was covered with clouds so the secondary target of Nagasaki was bombed.

Kokura

Nagasaki During World War II Nagasaki was one of the largest seaports in southern Japan. The city was important during the war because of great industrial activity. Most residences and industrial buildings were made of wood. Since the city had been permitted to grow without any strict zoning laws, most buildings and residences were constructed closely to each other.

The Bombing: Nagasaki Before After

Genetic Mutations from Exposure to Radiation

TABLE A: Estimates of Casualties Pre-raid population Hiroshima Nagasaki 255,000 195,000 Dead 66,000 39,000 Injured 69,000 25,000 Total Casualties 135,000 64,000

TABLE C: Percent Mortality at Various Distances Distance from X, in feet Percent Mortality 0-1000 93.0% 1000-2000 92.0 2000-3000 86.0 3000-4000 69.0 4000-5000 49.0 5000-6000 31.5 6000-7000 12.5 7000-8000 1.3 8000-9000 0.5 9000-10,000 0.0

TABLE D: Cause of Immediate Deaths Hiroshima Cause of Death Percent of Total Burns 60% Falling debris 30 Other 10 Nagasaki Cause of Death Percent of Total Burns 95% Falling debris 9 Flying glass 7 Other 7

General Douglas MacArthur signing the treaty to end WWII in the Pacific (on the deck of the USS Missouri)

Japanese Delegate signing the peace treaty to end WWII in the Pacific

American General Douglas MacArthur and Japanese Prime Minister Hirohito