Atomic Bombs and World War II

Topic: From Isolation to World War ( ) The isolationist approach to foreign policy meant U.S. leadership in world affairs diminished after World War I. Overseas, certain nations saw the growth of tyrannical governments that reasserted their power through aggression and created conditions leading to the Second World War. After Pearl Harbor, the United States entered World War II, which changed the country’s focus from isolationism to international involvement.

Content Statement: Use of atomic weapons changed the nature of war, altered the balance of power and began the nuclear age.

Expectations for Learning: Summarize how atomic weapons have changed the nature of war, altered the balance of power and started the nuclear age.

The Manhattan Project Early in 1939, the world’s scientific community discovered that German physicists had learned the secrets of splitting a uranium atom Fears soon spread over the possibility of Nazi scientists utilizing that energy to produce a bomb capable of unspeakable destruction

The Manhattan Project Code name for the American effort to design and build an atomic bomb The main assembly plant was built at Los Alamos, New Mexico The only color photo of the first atomic bomb explosion

The Manhattan Project Robert Oppenheimer was put in charge at Los Alamos Nearly $2 billion was spent on research and development of the atomic bomb The Manhattan Project employed over 120,000 Americans

The Manhattan Project Secrecy was paramount The project had to be kept secret from the Germans and the Japanese Roosevelt and Churchill agreed that the Stalin wouldn’t be told about the project Only a small group of scientists and officials knew about the atomic bomb’s development

The Manhattan Project Vice-President Truman never heard of the Manhattan Project until he became President July 16, 1945 at 5:30 A.M. – Tested the bomb – Alamogordo, New Mexico – First “mushroom” cloud Germany and Italy already surrendered

Japan Refused to Give Up American soldiers and civilians were weary from four years of war The Japanese military was refusing to give up their fight American forces were intensely fire- bombing Japanese cities Japan had an army of 2 million strong stationed in the home islands guarding against invasion

Japan Refused to Give Up Warned Japan – They still didn’t give up The decision: Should we drop bomb? – If yes--thousands of innocent Japanese people would be killed – If no--thousands of Americans would be killed

The Decision to Drop the Bomb For Truman, the choice to use the bomb was the most difficult decision of his life First, an Allied demand for an immediate unconditional surrender was made to the leadership in Japan The demand stated that refusal would result in total destruction, but no mention of any new weapons of mass destruction was made

Hiroshima The Japanese military command rejected the request for unconditional surrender On August 6, 1945, a plane called the Enola Gay dropped an atomic bomb on the city of Hiroshima

Hiroshima Instantly, 70,000 Japanese citizens were vaporized In the months and years that followed, an additional 100,000 perished from burns and radiation sickness

Nagasaki On August 9, a second atomic bomb was dropped on Nagasaki 80,000 Japanese people perished On August 14, 1945, the Japanese surrendered

Why Truman Used the Bomb Truman rejected using a demonstration of the atomic bomb to show the Japanese leadership that we had it He knew there was no guarantee the Japanese would surrender if the test succeeded He felt that a failed demonstration would be worse than none at all

Why Truman Used the Bomb A Normandy-type invasion would have cost an estimated million casualties Truman believed that the bombs saved Japanese lives as well Over 3,500 Japanese kamikaze raids had already wrought great destruction and loss of American lives

Results of Dropping the Bombs The dropping of the atomic bombs on Japan hastened the end of World War II and is considered the beginning of the nuclear age The use of these bombs introduced a new type of weapon capable of mass destruction

Only Superpower For 4 years after end of WWII the U.S. is only superpower because we have the atomic bomb This deterred the Soviet Union from expanding their influence over other countries

Postwar – United States Lost thousands of people during the war Country is stronger than ever after the war Capitalism – Economic system based on a free market, open competition, profit motive and private ownership of the means of production Believed the rest of the world should model us Want free elections, free trade, and business expansion all around the world

Postwar – United States The old world order is gone The U.S. could no longer be isolated The U.S. now relied on world trade to prosper

Postwar – Soviet Union Lost over 7 million people during the war Torn apart after the war Wanted to build a strong country Communism – A theory or system of social organization based on the holding of all property in common, actual ownership being ascribed to the community as a whole or to the state Believed the rest of the world should be communist

Beginning of the Cold War Cold War – War with no fighting – Instead of fighting, use military threats, espionage, propaganda, and politics Nuclear weapons developed The period right after World War II will begin 50 years of Cold War between the U.S. and the Soviet Union

Beginning of the Cold War The U.S. and Great Britain were allies with the Soviet Union for one reason--to beat Adolf Hitler – They did not trust Stalin  Did not tell him about the atomic bomb Stalin expected entire world to become communist U.S. and Soviet Union had very different views of the future

Soviet Union Tests Atomic Bomb 1949: Soviet Union tests and explodes atomic bomb This makes Soviet Union the 2 nd superpower

Arms Race Arms race between U.S. and Soviet Union – Occurred throughout Cold War – Guarantee security – The two sides competed with each other to make the most and best weapons for the next 50 years