On the morning of August 6, 1945, a B-29 bomber named EnolaGay flew over the industrial city of Hiroshima, Japan and dropped thefirst atomic bomb ever.
The city went up in flames caused by theimmense power equal to about 20,000 tons of TNT. The project was asuccess. They were an unprecedented assemblage of civilian, andmilitary scientific brain powerbrilliant, intense, and young, thepeople that helped develop the bomb. Unknowingly they came to anisolated mountain setting, known as Los Alamos, New Mexico, to designand build the bomb that would end World War 2, but begin seriouscontroversies concerning its sheer power and destruction.Order now
I becameinterested in this topic because of my interest in science andhistory. It seemed an appropriate topic because I am presentlystudying World War 2 in my Social Studies Class. The Hiroshima andNagasaki bombings were always taught to me with some opinion, and Ialways wanted to know the bomb itself and the unbiased effects that ithad. This I-search was a great opportunity for me to actually fulfillmy interest. The Manhattan Project was the code name for the US effortduring World War II to produce the atomic bomb.
It was appropriatelynamed for the Manhattan Engineer District of the US Army Corps ofEngineers, because much of the early research was done in New YorkCity (Badash 238). Sparked by refugee physicists in the UnitedStates, the program was slowly organized after nuclear fission wasdiscovered by German scientists in 1938, and many US scientistsexpressed the fear that Hitler would attempt to build a fission bomb. Frustrated with the idea that Germany might produce an atomic bombfirst, Leo Szilard and other scientists asked Albert Einstein, afamous scientist during that time, to use his influence and write aletter to president FDR, pleading for support to further research thepower of nuclear fission (Badash 237). His letters were a success,and President Roosevelt established the Manhattan Project.
Physicists from 1939 onward conducted much research to findanswers to such questions as how many neutrons were emitted in eachfission, which elements would not capture the neutrons but wouldmoderate or reduce their velocity , and whether only the lighter andscarcer isotope of uranium (U-235) fissioned or the common isotope(U-238) could be used. They learned that each fission releases a fewneutrons. A chain reaction, therefore, was theoretically possible, ifnot too many neutrons escaped from the mass or were captured byimpurities. To create this chain reaction and turn it into a usableweapon was the ultimate goal of the Manhattan Project.
In 1942 General Leslie Groves was chosen to lead the project,and he immediately purchased a site at Oak Ridge, Tenn. , forfacilities to separate the necessary uranium-235 from the much morecommon uranium-238. Uranium 235 was an optimal choice for the bombbecause of its unusually unstable composition. Thus, the race toseparate the two began. During that time, the work to perfect thefiring mechanism and structure of the bomb was also swiftly underway.
General Groves initial task had been to select a scientificdirector for the bomb project. His first two choices, Ernest O. Lawrence, director of the electromagnetic separation project, andArthur H. Compton, director of Chicago Metallurgical Laboratory, werenot available. Groves had some doubts regarding the next bestcandidate, J. Robert Oppenheimer (Wood 2).
Finally, Groves gambledon Oppenheimer, a theoretical mathematician, as director of theweapons laboratory, built on an isolated mesa (flat land area) at LosAlamos, New Mexico. After much difficulty, an absorbent barrier suitable forseparating isotopes of uranium was developed and installed in the OakRidge gaseous diffusion plant. Finally, in 1945, uranium-235 of bombpurity was shipped to Los Alamos, where it was fashioned into agun-type weapon. In a barrel, one piece of uranium was fired atanother, together forming a supercritical, explosive mass. To achievechain-reaction fission, a certain amount of fissile material, calledcritical mass, is necessary.
The fissile material used in theHiroshima model was uranium 235. In the bomb, the uranium was dividedinto two parts, both of which were below critical mass. The bomb wasdesigned so that one part would be slammed into the other by anexplosive device to achieve critical mass instantaneously (Badash238). When critical mass is achieved, continuous fission (a chainreaction) takes place in an extremely short period of time, and farmore energy is released than in the case of a gun-powder explosion(Badash 238).
On December 2, 1942, the first self-sustaining chainreaction with cadmium took place, overseen by Enrico Fermi, in theUniversity of Chicago squash fields (Asimov 783). Another type of atomic bomb was also constructed using thesynthetic element plutonium. Fermi built a reactor at Chicago in late1942, the prototype of five production reactors erected at Hanford,Wash. These reactors manufactured plutonium by bombarding uranium-238with neutrons. At Los Alamos the plutonium was surrounded with highexplosives to compress it into a super dense, super critical mass farfaster than could be done in a gun barrel.
The result was tested atAlamogordo, New Mexico, on July 16, 1945, and was the first explosionof an atomic bomb code-named Trinity (Beyer 55). However, all was not that easy coming up to this milestonepoint. Security restrictions bound both workers and townspeople. Everybody had the same address where all mail was censored (Wood 4). Everybody was restricted to a 200 mile radius, and residents of LosAlamos were prohibited from telling friends and relatives where theylived (Wood 4). There were serious issues of security of documents,due to failure to lock up (Wood 4).
The one serious incident was the hiring of Klaus Fuchs. Hewas later found, and convicted of obtaining secret documents andsending them to the Soviet Union. A competent and hardworkingscientist himself, Fuchs enabled the Soviet Union to create their ownatomic bomb (Beyer 45). Names were not allowed to be mentionedoutside of the laboratory. Everybody was a “sir” or “mister” insteadof their own name (Wood 4). Unless they worked at the lab themselves,wives knew nothing of their husbands research (Wood 4).
Decisions to drop the atomic bomb went through severalpersonalities, yet ultimately rested upon president Truman. The manwhose decisions created the Manhattan Project, never lived to see theresults of his labor. FDR died on April 12, three months before thefirst successful Trinity test (Beyer 56). The responsibilities weresoon placed upon Truman, the next president. Truman knew nothingabout the bomb and its effects yet hastily decided that the bomb beused on Japan, considering Germany was no longer a target with the warin Europe over. Initiated by Szilard, a petition was made to offerthe opinion that the bomb should be used only if Japan refused tosurrender, even after being informed of the bombs destructivecapabilities (Beyer 65).
Nevertheless, the decision was made that thebombs would be used until Japan surrendered. The Hiroshima model is known as a gun-barrel-type atomic bomb. Due to its long and narrow shape, the Hiroshima model was called “ThinMan” at first, but during the manufacturing process the original planswere modified, shortening the length and giving rise to the name“Little Boy. ” (Beyer 48). The energy released from the HiroshimaA-bomb was originally thought to be equivalent to the destructivepower of 20,000 tons of TNT. Later estimates, however, put the energyequivalent to approximately 15,000 tons of TNT, based on damage doneto buildings and research on the bomb’s composition.
Despite therelease of such enormous energy, it is believed that less than onekilogram of the 10 to 30 kilograms of uranium 235 housed in the bombachieved fission. The fissionable material used in the Nagasaki bomb wasplutonium 239. The plutonium 239 was divided into below-critical-massunits and packed into a spherical case. At the time of detonation, theunits were compressed to the center with a gun-powder explosion toachieve fission. The Nagasaki model is known as an implosion-typeatomic bomb.
Compared to the Hiroshima A-bomb, the one used inNagasaki was larger in diameter and round so it was called “Fat Man. ”Only slightly more than one kilogram of the plutonium 239 is thoughtto have achieved fusion, but the energy released is estimated to beequivalent to the destructive power of about 20,000 tons of TNT(Hewlett 215). Little boy killed about 100,000 people outright, woundedanother 100,000, and destroyed about 90 percent of Hiroshima (Hewlett216). Yet, while the first atomic bomb was a roaring success, itraised many ethical and controversial issues. Most of the people inthe United States of America supported the use of the atomic bomb,even President Truman called it, “the greatest thing in history”(Beyer 75). Many people, including the scientists that developed thebomb, opposed the bombings and felt that it was immoral to kill thatmany innocent people just to get an influence in the war.
The Manhattan Project was one of the most important parts ofAmerican History. It was the first effort to create an atomic bomb,that helped end the war in the Pacific. I enjoyed researching thetopic and learned a lot from my readings. Now I understand the atomicbomb better and also understand the motives behind it. Researchinghelped me understand the sheer strength and power of what a smallelement can do.
All of our lives have changed through the developmentand bombing of the atomic bomb. The cold war, nuclear restrictions,nuclear energy, are all results of the first nuclear breakthrough. However, the controversial issues will still rage on. Nucleartesting, nuclear power, and nuclear waste are still being debated forover 50 years, and the United States, the only country to actually usethe bomb, is the leader.