Download The Manhattan Project - 20th Century American

Guided Readings: Secondary
The Manhattan Project
1941–1945
The development of Manhattan Project took place around the same time that many
discoveries were being made in neutron physics and reactions. During this time, the political
situation in the world was changing. Japan had been dominating the Pacific. It had invaded
Manchuria in September 1931. In addition, Nazi Germany rose and expanded when Adolf
Hitler became Chancellor of the country in January 1933. Political and social repression,
instability, and military violence were becoming prevalent in European countries such as
Italy and Spain.
During this time, Leo Szilard, a Hungarian-American physicist, began considering the
development of an atomic bomb. Around the same time, the process of fission was
discovered. Szilard realized that atomic energy developed from a possibility to a probability.
He drafted a letter to Albert Einstein. Einstein then forwarded the letter to President Franklin
D. Roosevelt. The letter warned the president about the possibility of nuclear weapons in
other countries, especially Nazi Germany. The first successful attempt to split the atom had
been done in Germany in 1937. The letter was delivered to Roosevelt on October 10, 1939.
Ten days later, the first meeting of the Advisory Committee on Uranium took place in
Washington, D.C. It was known as the Briggs Uranium Committee.
In the United States, there was a significant lack of interest in atomic weaponry.
However, key developments in the situation were occurring in England. Otto Frisch and
Rudolf Peierls prepared a theoretical analysis on possible fast fission in February 1940. Their
analysis contained estimated sizes for the bomb. It also included some designs for the bomb
itself. Study committees were formed at a high level of the government. One of the
committees that formed on April 10, 1940 was the MAUD Committee. (The name of the
MAUD Committee was taken from part of a coded message sent by Neils Bohr to Otto
Frisch early in the program.) The report stated that gaseous diffusion was the best form of
uranium enrichment. Toward the end of 1940 and into 1941, research on the atomic bomb
started up again in the United States. Important discoveries were made. But there was no
support from the federal government. Still, the discoveries that were made were significant.
Philip Abelson had developed uranium enrichment. On February 26, 1941, Glenn Seaborg
and Arthur Wall discovered plutonium. By July, plutonium became the most superior fissile
material. The MAUD Committee completed its final report on the atomic bomb. The
committee then put together proposals to build one.
On December 18, 1941, a United States project on the investigation of atomic weapons
began. It was known as the S-1 Project. It was led by Arthur H. Compton, who directed a
team of scientists to work on resources for the bomb. In January 1942, Enrico Fermi’s work
with graphite and uranium led to beginning designs for the CP-1. It was the first nuclear
reactor. The reactor was being classified as a weapons project. It had to be brought into an
organization with experience in weapon design. On June 18, 1942, Colonel James Marshall \
CICERO © 2008
1
Guided Readings: Secondary
had the Army Corps of the Engineers District take the atomic bomb plans and move them to a
new group called the Manhattan Engineer District. This was more
commonly known as the Manhattan Project. Colonel Leslie Richard
Groves took control of the Manhattan Project on September 17,
1942. Groves purchased mass amounts of uranium. He also bought
52,000 acres of land. Groves had disagreed with the scientists, but
he also maintained great leadership during this time.
Companies such as Du Pont and the Kellogg Corporation
began to have management roles in the fissile material programs for
the atomic bomb. A central laboratory for the bomb was built. It was
called Project Y. Groves had Dr. J. Robert Oppenheimer lead the project. In 1944, work on
the bomb continued. Oppenheimer and his scientists were working long hours each day.
Weapons development continued as well, as did the production of fissile material and combat
delivery productions. However, many problems began to surface during the construction of
the bomb. By May 1944, there was little success in reaching the first successful implosion.
Implosion means taking radioactive plutonium and compressing it by setting off explosions
all around it at the same time. When it gets compressed to a certain point, the chain reaction
will take place in the plutonium, releasing the atomic energy, and the much greater nuclear
blast.
Geoffrey Taylor and James Tuck, two British scientists, joined the Manhattan Project
in order to work on how the bomb would implode. An enrichment plant was built at Oak
Ridge to help with the electromagnetic structure of the atomic bomb. On July 4, 1944,
Oppenheimer showed off plans of Emilio Segre’s fission measurements. These measurements
led to a significant turning point in the Manhattan Project. By now, the planned plutonium
gun, which would force two masses of plutonium into each other, had been abandoned.
Implosion became Oppenheimer’s top priority. He and his team had only twelve months to
go before the weapon was supposed to be delivered.
The Manhattan Project began to have more problems in September 1944. Leaks in the
project began to occur. Plutonium production had not yet started. Production techniques did
not look like they would be successful. One of these errors occurred on September 26, 1944.
This was when the first full scale plutonium reactor was completed and loaded with uranium.
Known as the B pile, it shut down for no reason. It then started back up by itself the next day.
But as 1945 started, things began to improve for the Manhattan Project. Production began to
increase at a rapid pace. In addition, uranium bombs were finalized and assured for success.
Plutonium bombs were scheduled to meet the August 1 deadline. However, President
Franklin D. Roosevelt died suddenly on April 12. Harry S. Truman then became president.
He was informed in detail about the Manhattan Project. Truman decided to continue with the
project. Meetings were then held to decide on which enemy cities the United States would
drop the bomb on during World War II. Germany was ruled out. It surrendered to the Allied
CICERO © 2008
2
Guided Readings: Secondary
Forces on May 8, 1945. The bombs were finally tested at the Trinity Site on July 16, 1945 in
New Mexico. After the tests were ruled a success, they were approved to be dropped on the
cities of Hiroshima and Nagasaki in Japan. The bombs were dropped on Hiroshima and
Nagasaki on August 6 and 9, respectively. These bombings led to the surrender of Japan and
the end of World War II.
CICERO © 2008
3
Guided Readings: Secondary
Name: _______________________
The Manhattan Project
Discussion Questions:
1. What did the letter by Leo Szilard and Albert Einstein warn President Franklin D.
Roosevelt about? What was the result of this letter?
2. Do you feel that with all the political turmoil that was occurring in the world the
planning and eventual construction of an atomic bomb was necessary? Why?
3. How was the year 1941 considered to be a successful year for atomic development?
4. What happened after the CP–1 nuclear reactor was classified as a weapons project?
CICERO © 2008
4
Guided Readings: Secondary
5. Do you feel it was necessary for mainstream companies such as Du Pont and the
Kellogg Corporation to have management roles in the fissile materials programs for
the atomic bomb?
6. What was the significant turning point in the development of the Manhattan Project?
7. What problems did the Manhattan Project begin to have starting in September 1944?
8. Do you think dropping the atomic bomb on Japan was necessary in order to end World
War II? Why?
CICERO © 2008
5
Guided Readings: Secondary
Answer Key
The Manhattan Project
1. What did the letter by Leo Szilard and Albert Einstein warn President Franklin D.
Roosevelt about? What was the result of this letter?
The letter by Leo Szilard and Albert Einstein warned President Franklin D. Roosevelt
about the possibility of nuclear weapons in other countries. The letter had been
delivered to Roosevelt on October 10, 1939. Ten days later, the first meeting of the
Advisory Committee on Uranium took place in Washington, D.C. It was known as the
Briggs Uranium Committee.
2. Do you feel that with all the political turmoil that was occurring in the world the
planning and eventual construction of an atomic bomb was necessary? Why?
Answers will vary?
3. How was the year 1941 considered to be a successful year for atomic development?
The year 1941 was considered to be a successful year for atomic development because
important discoveries were made. Philip Abelson had developed uranium enrichment.
On February 26, 1941, Glenn Seaborg and Arthur Wall discovered plutonium. By July,
plutonium had become the most superior fissile material. The MAUD Committee,
which was an atomic study committee, completed its final report on the atomic bomb.
They also started putting together proposals that would lead to the construction of an
atomic bomb.
4. What happened after the CP–1 nuclear reactor was classified as a weapons project?
When the CP–1 nuclear reactor was classified as a weapons project, it needed to be
brought into an organization that had experience with designing weapons. On June 18,
1942, Colonel James Marshall had the Army Corps of the Engineers District take the
atomic bomb plans and move them to a new group called the Manhattan Engineer
District. This district was more commonly known as the Manhattan Project. Led by
Colonel Leslie Richard Groves, he bought massive amounts of uranium and bought
52,000 acres of land.
5. Do you feel it was necessary for mainstream companies such as Du Pont and the
Kellogg Corporation to have management roles in the fissile materials programs for
the atomic bomb?
Answers will vary
6. What was the significant turning point in the development of the Manhattan Project?
The significant turning point in the Manhattan Project occurred on July 4, 1944, when
Manhattan Project figurehead J. Robert Oppenheimer showed plans of Emilio Segre’s
fission measurements. This caused plans for the plutonium gun to be shelved.
CICERO © 2008
6
Guided Readings: Secondary
Implosion of the atomic bomb now became Oppenheimer’s main priority.
7. What problems did the Manhattan Project begin to have starting in September 1944?
Problems with the Manhattan Project first started in September 1944. Leaks in the
project began to happen. The mass production of plutonium did not occur as planned.
Production techniques for the atomic bomb did not look like they would be successful.
In addition, the first full scale plutonium reactor was completed and loaded with
uranium. It was called the B pile. However, it shut down for no reason, but then started
up by itself the next day. Scientists did not know what was wrong with it.
8. Do you think dropping the atomic bomb on Japan was necessary in order to end World
War II? Why?
Answers will vary.
CICERO © 2008
7