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The atom bomb is one of the most important discoveries in modern day science.
Countless scientists worked relentlessly on the project and their efforts
opened the door for present and future exploration of the atom.
Just before the beginning of World War II, Albert Einstein wrote a letter to
President Franklin D. Roosevelt. Urged by Hungarian-born physicists Leo
Szilard, Eugene Wingner, and Edward Teller, Einstein told Roosevelt about Nazi
German efforts to purify Uranium-235 which might be used to build an atomic
bomb. Shortly after that the United States Government began work on the
Manhattan Project. The Manhattan Project was the code name for the United
States effort to develop the atomic bomb before the Germans did. "The first
successful experiments in splitting a uranium atom had been carried out in the
autumn of 1938 at the Kaiser Wilhelm Institute in Berlin" Just after Einstein
wrote his letter. So the race was on. Major General Wilhelm D. Styer called
the Manhattan Project "the most important job in the war . . . an all-out
effort to build an atomic bomb." It turned out to be the biggest development
in warfare and science’s biggest development this century.
The most complicated issue to be addressed by the scientists working on the
Manhattan Project was the production of ample amounts of enriched uranium to
sustain a chain reaction. At the time, Uranium-235 was hard to extract. Of the
Uranium ore mined, only about 1/500th of it ended up as Uranium metal. The
Uranium metal is relatively rare, occurring in Uranium at a ratio of 1 to 139.
Separating the one part Uranium-235 proved to be a challenge. No ordinary
chemical extraction could separate the two isotopes. Only mechanical methods
could effectively separate U-235 from U-238. Scientists at Columbia University
solved this difficult problem.
A massive enrichment plant was built at Oak Ridge, Tennessee. H. C. Urey and
his associates and colleagues at Columbia University designed a system that
worked on the principle of gaseous diffusion. After this process was
completed, Ernest O. Lawrence from the university of California in Berkeley
implemented a process i nvolving magnetic separation of the two isotopes.
Finally, a gas centrifuge was used to further separate the Uranium-235 from
the Uranium-238. The Uranium-238 is forced to the bottom because it had more
mass than the Uranium-235. This Uranium was then transported to a laboratory
headed by J. Robert Oppenheimer. Oppenheimer was the major force behind the
Manhattan Project. He literally ran the show and saw to it that all of the
great minds working on this project made their brainstorms work. He oversaw
the entire project from its conception to its completion. Once the purified
Uranium reached New Mexico, it was made into the components of a gun-type
atomic weapon. The scientists were so confident that the gun-type atomic bomb
would work that no test was conducted and it was first employed in military
action over Hiroshima, Japan, on Aug. 6, 1945.
Once again the University of Chicago, under Enrico Fermi’s direction built the
first reactor. This led to the construction of five large reactors at Hanford,
Wash., where U-238 was irradiated with neutrons and changed into plutonium.
The plutonium was sent to Los Alamos.
There was a debate at Los Alamos about whether to test the new plutonium
‘implosion’ bomb before it was actually dropped. "Harvard explosives expert
George B. Kistiakowsky and Oppenheimer both argued for such a test, but
initially Groves was opposed. He was afraid that if the test failed, the
precious plutonium would be scattered all across the countryside."(Szasz 26)
Brigadier General Leslie R. Groves, the man the army placed in charge, was
eventually persuaded. Hanford’s plutonium production was increasing fast
enough so that a test would cause little delay in time. They feared that if
they dropped the untested plutonium bomb and it failed to work, "the enemy
would find themselves owners of a ‘gift’ atomic weapon."(Szasz 26) The final
agreement for the test was that the bomb would be placed in "a gigantic,
214-ton, cylinder-shaped tank (called ‘Jumbo’)."(Szasz 26) If the plutonium
correctly fissioned, the tank would be vaporized. If it did not work
correctly, the conventional explosives would be contained in the tank and the
plutonium would stay in the tank. After further development of the implosion
design and fears that "Jumbo" would dramatically distort all "their
complicated instrumentation-the raison d’être for the test,"(Szasz 36) the
world’s largest pressure tank was not used.
On Monday, July 16, 1945, at 5:29:45 A.M., Mountain War Time, a plutonium bomb
ignited at the Trinity site, a remote site in the New Mexico desert. "The
explosion created s brilliant flash that was seen in three states. There were
many reports from civilians from all over that described the experience.
People who saw it said it looked like the sun had risen for a few minutes and
then went back down. Others thought they had seen a large plane or meteor
crash. A sheep herder who was laying sleeping on a cot fifteen miles away was
blown off. The Smithsonian Observatory on Burro Mountain confirmed a shock but
noted that the vibrations were unlike any earthquake ever recorded. An eight
year-old boy was awakened and ran for his Methodist parents, and they
considered if this might be the end of the world. The most powerful statement
that has been cited in practically every coverage of the atomic bomb is
Georgia Green’s experience. She was being driven to Albuquerque. "What was
that?" she asked her brother-in-law, who was driving. This was very unusual
because Georgia Green was blind. Brigadier General Farrell wrote a letter for
the Secretary of War. "’No man-made phenomenon of such tremendous power had
ever occurred before . . . Thirty seconds after the explosion came, first, the
air blast pressing hard against people and things, to be followed almost
immediately by the strong, sustained, awesome roar which warned of doomsday
and made us feel that we puny things were blasphemous to dare tamper with
forces heretofore reserved to the Almighty. Words are inadequate tools for the
job of acquainting those not present with the physical, mental and
psychological effects."
Upon witnessing the explosion, reactions among the bomb’s creators were mixed.
Their mission had been successfully accomplished, however, they questioned
whether "the equilibrium in nature had been upset—as if humankind had become a
threat to the world it inhabited." Oppenheimer was ecstatic about the success
of the bomb. Many people who were involved in the creation of the atomic bomb
signed petitions against dropping the bomb.
The atomic bomb has been used twice in warfare. The Uranium bomb nicknamed
"Little Boy," which weighed over 4.5 tons, was dropped over Hiroshima on
August 6, 1945. At 0815 hours the bomb was dropped from the Enola Gay. It
missed Ground Zero at 1,980 feet by only 600 feet. At 0816 hours, in the flash
of an instant, 66,000 people were killed and 69,000 people were injured by a
10 kiloton atomic explosion.
Nagasaki fell to the same treatment as Hiroshima on August 9, 1945. The
plutonium bomb, "Fat Man," was dropped on the city. It missed its intended
target by over one and a half miles. Nagasaki’s population dropped in one
split-second from 422,000 to 383,000. 39,000 were killed, over 25,000 were
injured. That blast was less than 10 kilotons as well. Physicists who have
studied the atomic explosions conclude that the bombs utilized only 0.1% of
their respective explosive capabilities.
Controversy still exists about dropping the two atomic bombs on Japan.
Arguments defending the Japanese claim "the atomic bomb did not win the war in
the Pacific; at best, it hastened Japanese acceptance of a defeat that was
viewed as inevitable." Other arguments state that the United States should
have warned the Japanese, or that we should have invited them to a public
demonstration. On the other side, advocates claimed that the invasion of the
Japanese islands could and would result in over one million military
casualties plus the civilian losses based on previous invasions of Japanese
occupied islands.
Science Essays
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