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 additionalpeople 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
Hiroshima Nagasaki
Pre-raid
population
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