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