Hiroshima and Nagasaki: Were
the Atomic Bombs Necessary?
IB History of the Americas
“My God, What Have We Done?” John
Lewis, Co-Pilot of the Enola Gay
Hiroshima and Nagasaki
Japan
• The atomic bomb named "Little
Boy" was dropped on
Hiroshima by the Enola Gay, a
Boeing B-29 bomber, at 8:15 in
the morning of August 6, 1945.
“Fat Man” was dropped on
Nagasaki 3 days later on
August, 9, 1945.
• 140,000 Killed in
Hiroshima (mostly
civilians)
• 74,000 Killed in Nagasaki
(mostly civilians)
What Is the Atomic Bomb?
• The atomic bomb is a
nuclear weapon that derives
its destructive force from the
nuclear reaction of fission
• So powerful- a single
weapon is capable of
destroying an entire city.
Post WWII model of the “Little Boy” atomic bomb
dropped on Hiroshima.
www.atomicarchive.com
Hiroshima Blast
Bomb had a height of 580 meters and then
erupted into an enormous fireball like the
sun.
More than a million degrees Celsius at its
center, the fireball reached a maximum
diameter of 280 meters in one second.
Surface temperatures near the hypocenter
rose to 3,000-4,000℃.
Damage to Buildings
90 percent of all buildings burned or destroyed beyond repair.
Effects
• Detonation of atomic weapons have many
effects, both short and long term, including
thermal effects, blast effects, and
radiation.
www.atomicarchive.com
Radiation
.
Those exposed within about
1000 meters of the
hypocenter
received life-threatening
doses, and most died
within a few days.
Leukemia and other cancers
appeared over the course
of 2 to 20 years, and
radiation effects still
threaten the health of the
survivors.
Birth Defects
Radiation harmed fetuses in various ways.
Some were stillborn.
Some children were born without obvious
problems but had higher mortality rates
Development tended to be slower than that
of other children.
Microcephaly
Those who were exposed
close to the hypocenter in
early pregnancy were
likely to display
microcephaly (abnormally
small heads)
accompanied by severe
mental retardation that
renders them unable to
manage everyday life
without assistance.
The Blast Pressure
The wind velocity on the
ground beneath the
explosion center was
980 miles/hr, which is
five times stronger
than the wind
generated by strong
hurricanes
Blast Effects
The effects of the blast wave on a
typical wood framed house.
http://www.atomicarchive.com/Effects/effects3.shtml
www.atomicarchive.com
• This heat cause a
high-pressure wave to
develop and expand
outwards, creating the
blast effect. The front
of the blast wave,
known as the shock
front, is a wall of
highly compressed
air.
Relief
The atomic bomb instantaneously destroyed the
government offices, City Hall, the police stations,
and all government buildings.
The next day, the Japanese Army Marine
Headquarters which sustained only slight
damage, took the lead in establishing the
Hiroshima Security Regiment Headquarters.
The military, the government, and the people
united to carry out relief activities, often with little
understanding of the effects of radiation.
Manhattan Project
The Manhattan Project was created in order to
establish the first nuclear bomb that would help to end
World War II in the Pacific.
Top scientists from around the world such as J.
Robert Oppenheimer, Enrico Fermi, and Albert
Einstein, along with many of the Army Corps of
Engineers’ finest were recruited to work on the
project.
Although called the Manhattan Project it was no
where near the location of Manhattan. Rather, it was
about 2500 miles away in Los Alamos, New Mexico.
http://en.wikipedia.org/wiki/Manhattan_Project
J. Robert Oppenheimer, Director of
the Manhattan Project
“We knew the world would not be
the same. A few people
laughed, a few people cried,
most people were silent. I
remembered the line from the
Hindu scripture, the BhagavadGita. Vishnu is trying to
persuade the Prince that he
should do his duty and to
impress him takes on his multiarmed form and says, ‘Now, I
become Death, the destroyer
of worlds.’ I suppose we all felt
that one way or another.”
Effects
• Social: By the end of the conflict with Japan the world
began to realize the power that one country can have.
Seeing this we learn later that it only takes one
strategically positioned nuclear warhead to cause the
world to end. People were effected by this
psychologically in that they created bomb shelters and
survival plans.
• Political: Once the war ended politics became a totally
different ballpark. The United States entered the Cold
War against the USSR and was pushed into an arms
race led by the political engines of both nations.
• Economic: During WWII, the manufacture and
distribution of nuclear arms was not much of a threat due
to the fact that only the US had them in its arsenal.
Arguments for Dropping the Atomic
Bomb
1. Save (1,000,000?) American and Japanese lives. Japanese resisted US
forces by use of Kamikaze pilots in Okinawa and fighting without surrender
at Iwo Jima and other battles. They didn’t surrender after the fire bombing
of major cities, nor after Hiroshima.
2. End the war quickly. The US was tired after 4 years of war. Germany had
already surrendered in May, 1945. Japan resisted an unconditional
surrender.
3. Demonstrate US power to the world.
4. Racism. US policy makers expressed racist attitudes toward Japanese
5. Revenge. Truman suggested after the war that he wanted to exact revenge
for Pearl Harbor.
6. Large resources went into the development of the atomic bomb, and there
was a desire to use it and test it.
7. As an unelected President, Truman was controlled by his close advisors who
favored using the bomb. Kept in the Dark as VP under FDR.
Arguments Against Dropping the
Bomb
1. Moral failure for being the only country to use an atomic bomb in war. The
attack struck mainly civilians who outnumbered military personnel 6:1.
2. Japan may have been ready to surrender. It was blockaded. Its navy and
air force was destroyed. It’s overseas possessions were confiscated.
3. The US needlessly insisted upon an unconditional surrender, since Japan
was willing to surrender if it could retain the Emperor.
4. US moral authority, nationally and internationally, was weakened.
5. Contributed to mistrust held by the USSR and prompted a dangerous arms
race.
6. Some argue there was no need for the second bomb on Nagasaki.
7. There were many prominent military personnel against dropping the bomb,
like Eisenhower, under-Secretary of the Navy, Ralph Bard, Army Chief of
Staff General George C. Marshall, and Admiral Chester W. Nimitz,
Commander in Chief of the Pacific Fleet.
8. Couldn’t they have dropped the bomb in the water as a threat to force the
surrender?