Transcript Dropping the Atomic Bombs

Dropping the Atomic Bombs
HIROSHIMA AND NAGASAKI
JAPAN
AUGUST 6 and 9, 1945
What’s Happening in Europe and U.S.
• April 1945
– FDR dies and Truman takes over the presidency.
• May 7, 1945
– Germany surrenders.
• Still have to deal with Japan.
The Decision
• In Japan, part of the military-dominated Japanese
government had begun to realize that a way had
to be found to negotiate and end to the war
peacefully. However, the Allied demand for
“unconditional surrender” was regarded as
unacceptable.
• Under Secretary of State Joseph Grew nonetheless
argued that the Japanese might surrender if
allowed to retain their Emperor. He also felt that
the Emperor would be “the sole stabilizing force”
that would make the Japanese armed forces
accept a surrender order.
The Decision
• The few people who knew about the Manhattan
Project always assumed that the atomic bomb
would be used against Germany or Japan. Many
of those people thought it could be used to end
the war.
• Harry S. Truman, who became President after
Roosevelt’s death, had no knowledge of the
atomic bomb until he was confronted with the
decision to use it or not. He saw the atomic bomb
principally as a means to end the war quickly and
save American lives by not invading Japan.
The Decision
• Tensions grew between the Soviet Union and the
United States, especially in terms of Soviet
domination of Poland and other Eastern European
countries (Spring 1945). American possession of
the atomic bomb might help make the Soviets
work cautiously in Europe and elsewhere.
The Decision
• Some Manhattan Project scientists felt that the
bomb project had been a response to a threat
from Germany. Attacking Japan without first
providing a warning and an opportunity to
surrender, would weaken, “our moral position...in
the eyes of the world.”
• They also were concerned that without telling the
Soviets first, the use of the bomb would increase
the chances of an uncontrolled nuclear arms race.
• These concerns did not reach Truman.
The Decision
• The decision to drop the bomb was made in an
effort to save American lives. Estimates of the
number of American casualties that the planned
invasion of Japan would have cost varied widely.
One estimate set the number at 31,000. Added to
the American losses would be many Japanese
casualties, both military and civilian. To prevent
an invasion and to save as many lives as possible,
Truman chose to use the atomic bomb.
The Bombs
Little Boy
Fat Man
• Hiroshima
• Weight = 4 tons
• Energy released: equivalent
to 12.5 kilotons of TNT
• Nagasaki
• Weight = 5 tons
• Energy released: equivalent
to 20 kilotons of TNT
Locations
Hiroshima
Nagasaki
• August 6, 1945
• August 9, 1945
The Delivery
B-29 Bomber named Enola Gay
The Blast
• Little Boy was detonated 1,900 feet above
Hiroshima, Japan.
• Over 5.4 million degrees Fahrenheit.
• A fireball formed in 0.1 millisecond, with a
temperature of 540,000 degrees Fahrenheit.
• The top of the atomic cloud reached an altitude of
17,000 meters.
• Radioactive debris was deposited by "black rain"
that fell heavily for over an hour over a wide area.
• This bronze Buddha
statue was melted by
heat from the bomb.
Bronze melts at around
1700 degrees F. The
temperature on the
ground beneath the
exploding bomb
reached about 7000
degrees.
The Effects
Hiroshima
Nagasaki
Before
After
The Immediate Effects
The Immediate Effects
• Thermal Heat. Intense thermal heat caused severe
burns and loss of eyesight. Thermal burns of bare skin
occurred over 2 miles from ground zero. Most people
exposed to thermal rays within 1 mile radius of ground
zero died.
• Acute symptoms. Symptoms appearing in the first four
months were called acute. Besides burns and wounds,
they included: general malaise, fatigue, headaches,
loss of appetite, nausea, vomiting, diarrhea, fever,
abnormally low white blood cell count, bloody
discharge, anemia, loss of hair.
The Later Effects
• Even the people who managed to survive
continue for a long time to suffer from
aftereffects such as keloid scars, atomic bomb
cataract, microcephaly, leukemia and cancer.
Results for the War
• The bombs effectively forced Japan to
surrender.
• After the war the U.S. occupied Japan and
helped it rebuild.