Download Unit 2: The Second World War and the Americas (1933*1945) Bullet

Unit 2: The Second World War and the Americas (1933–1945)
Bullet 5: Reasons for, and significance of, US use of atomic weapons
against Japan
1
The Dropping of The Atomic
Bomb at Hiroshima and Nagasaki
“The atom bomb was no great decision. It was merely
another powerful weapon in the arsenal of
righteousness.”
~ Harry S. Truman (POTUS)
2
Nuclear Programs:
Germany
Germany started experimenting with Nuclear
Fission in 1938.
German scientist Otto Hahn and Fritz Strassman
bombarded Uranium with neutrons and
discovered Barium atoms.
Conclusion: Nuclear fission releases a massive
amount of energy
3
No Bomb for the
Germans
June 1942 – German atomic program slows down
because Germany felt victory in WWII was
imminent.
U.S. and Britain were not aware that the Germans
decided not to build a bomb.
Japan also had an atomic program but was not
successful.
If Germany and Japan had created an atomic
bomb, it would be used against the Allies.
4
The Manhattan Project
June 1942, atomic-bomb project was controlled by
War Department's Army Corps of Engineers.
American and European physicists discovered that
the fission of uranium could a powerful weapon.
Major General Leslie Groves named head of the
project.
At the height of construction in mid 1944, the
Project employed nearly 129,000 people. No other
nation in the world had the massive industrial
capacity to make this possible.
5
Robert J. Oppenheimer
Late in 1942, Gen. Groves chose physicist J. Robert
Oppenheimer to head a new laboratory devoted
to the designing atomic bombs.
Oppenheimer recommended a remote site in New
Mexico for the new facility, where many famous
scientists could work together in complete
secrecy.
From a wealthy N.Y. Jewish family.
Ties with Communism
6
The Manhattan Project
Success
Two atomic bombs were made, “Little Boy” and
“Fat Man.”
Scientists at Los Alamos were not fully confident in
the “Fat Man” bomb.
Bombs designed to create an accurate and
symmetrical implosion.
7
Fat Man and
Little Boy
“Fat
Man”
“Little
Boy”
8
Battle of Okinawa
Known as “Typhoon of
Steel”
9
Deciding to Drop the
Bomb
10
1.
2.
3.
4.
5.
Deciding to Drop the
Bomb
Ending the war at the earliest possible moment
To justify the cost of the Manhattan Project
To frighten the Soviets
A lack of incentives not to use the bomb
Responding to Pearl Harbor
11
Ending the war at the
earliest possible moment
The primary objective for the U.S. was to win the war at
the lowest possible cost. Specifically, Truman was
looking for the most effective way to end the war
quickly, not for a way to not use the bomb.
- Allied prisoners of war were beaten, deliberately
starved, tortured, worked to death and even
experimented on with chemical & biological weapons
by the Japanese.
- Some were even crucified on trees and beheaded
by their captors!
12
Ending the war at the
earliest possible moment
14
To justify the cost of the
Manhattan Project
15
To Frighten the Soviets
• At the Yalta Conference in March 1945, the big
three agreed that there should be early free
elections in Eastern European countries like Poland
as soon as the war was over.
RIP
16
To Frighten the Soviets
• By the time the big three met again at Potsdam on
23rd July 1945, Stalin did not trust the Americans.
He is trying to spread
Communism!
We have been attacked twice
in less than 25 years!
17
A lack of incentives not
to use the bomb
• By 1945, the
bombing of civilians
was already an
established
practice.
18
Responding to Pearl
Harbor
• When a general raised objections to the use of the bombs,
Truman responded by noting the atrocities of Pearl Harbor and
said that “When you have to deal with a beast you have to
treat him as a beast.”
• On 7th December 1941, 2400 American servicemen, six
battleships and ten other ships were destroyed during a
surprise attack by the Japanese.
19
Alternatives to dropping
the bomb
1. Intensifying conventional bombing and the naval
Blockade
2. Allowing the Japanese to retain the Emperor
3. Waiting for the Soviet Union to enter the war
20
Formal
Warning
to
Japan
21
22
1
23
Imperial Rescript on
Surrender
24
Post-war Impact of
Atomic Bomb
• Changed the very nature of
war
o Presented the possibility of annihilation of
humankind
25
Post-war Impact of
Atomic Bomb
• US held an atomic monopoly until
1949
o Huge US-USSR arms race followed
o Eventually led to Mutually Assured Destruction
(1967)
26
Post-war Impact of
Atomic Bomb
• Nuclear weapons prove to not be a reasonable
option in limited wars
• This seen in the Korean and Vietnam War