Little Boy (gun-type design)
Fat Man (implosion type)
Photos from:
http://www.atomicheritage.org
Sources:
http://www.atomicheritage.org/history/science-behind-atom-bomb
http://www.ucsusa.org/nuclear-weapons/how-do-nuclear-weapons-work#.WQaF4GQrI1g
Sunday, April 30, 2017
Nuclear Chemistry- The Atom Bombs Used in the Second World War
The United States developed two types of atomic bombs during the Manhattan Project in World War Two. The first was a bomb codenamed Little Boy. Little Boy was a gun-type weapon, meaning that it was developed to cause more casualties than its counter part, Fat Man. Fat Man was an implosion-type weapon, which means that it was developed to cause immense damage to the area that it was dropped on. Little Boy was dropped first and was dropped on Hiroshima, while Fat Man was dropped second and was dropped on Nagasaki. Little Boy had a uranium core, while Fat Man had a plutonium core. The isotopes used were uranium-235 and plutonium-239, because both readily undergo fission. In atomic bombs, fission occurs when a neutron strikes the nucleus of an atom of a radioactive isotope, such as uranium-235 and plutonium-239, which splits the nucleus into separate fragments, releasing a massive amount of energy. This becomes a self-sustaining process inside of the atomic bomb, creating more fission amongst the atoms, because neutrons produced by the the fission, strike nearby nuclei. This is a chain reaction and is what caused the atomic explosions in Hiroshima and Nagasaki. The longest part of the Manhattan Project was the scientists trying to find the critical mass need of both uranium-235 and plutonium-239, in order for the atomic bomb to successfully create large enough explosions. This means that the scientists had to find the correct amount of the isotopes, that would allow for enough neutrons to be produced by the fission and strike the nuclei of other atoms, creating the chain reaction needed to create a chain reaction inside of the atomic bombs. Little Boy was constructed in a way so that there were two separate masses of uranium-235, and these two masses would quickly combine to avoid spontaneous fission of the atoms, which would cause the bomb to fizzle and fail to detonate. Spontaneous fission was one of the main issues that the scientists who were involved in the Manhattan Project encountered. Fat Man needed a different design, than that of Little Boy, because the plutonium isotope used for the core had a fission rate that was too high for the gun-type design. The isotope's high fission rate would cause the atoms to undergo spontaneous fission before the gun-type design could bring the two masses of plutonium together. Scientists created a new design that would quickly consolidate the plutonium, increasing the pressure and density, in turn allowing for the plutonium to reach its critical mass. For both bombs, once the critical mass was reached, a chain reaction was formed. Once the chain reactions were formed inside of the atomic bombs, they could be successfully detonated.
Little Boy (gun-type design)
Fat Man (implosion type)
Photos from:
http://www.atomicheritage.org
Sources:
http://www.atomicheritage.org/history/science-behind-atom-bomb
http://www.ucsusa.org/nuclear-weapons/how-do-nuclear-weapons-work#.WQaF4GQrI1g
Little Boy (gun-type design)
Fat Man (implosion type)
Photos from:
http://www.atomicheritage.org
Sources:
http://www.atomicheritage.org/history/science-behind-atom-bomb
http://www.ucsusa.org/nuclear-weapons/how-do-nuclear-weapons-work#.WQaF4GQrI1g
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Hey "19mnason"! Great post! I too am interested in the history and sciences behind the atom bombs that were used in World War II and really anything related to World War II. I didn't know prior to reading this that the "Fat Man" and the "Little Boy" were two differently designed bombs tasked to do certain things. One being a gun type weapon that was used to have more casualties and the other to cause more destruction. It's interesting to think about the mind process that the scientists during the development of these weapons were. Did they truly know what kind of impact this would have to the environment and the aftermath that would follow from the amounts of radiation that these bombs left. The different isotopes of uranium and plutomium that were used to house these bombs must have been a struggle for the scientists to choose from. I can not even begin on what must traits each of the isotopes must meet in order to render them acceptable for casing the atomic weapons. Besides being able to under go fission to release the energy. Anyways, it was a very interesting read and I am looking forward to perhaps learn more about the magnitudes of the energy that can come from nuclear fission in either chemistry class or even US history when we discuss World War II. Although I doubt we'll go into detail on such a specific item such as atomic bombs used in World War II.
ReplyDeleteHey what's going Mnason, just read your article and found it quite interesting. Prior to reading, I stumbled upon Garret's post where he recommended me to your entry. I would recommend it to anyone before reading your article because I found it quite pertinent as it provided a comprehensive overview for the terminology as well as the various concepts found in the study of nuclear chemistry, further elaborated in your research paper. One concept of the Fat Man and Little Boy was the method of detonation. I found the images to be useful but would you care to d elaborate upon the specific reaction that sets the chain of events into motion when it comes to the isotopes and the quantity needed to allow for the aforementioned neutrons to strike the nuclei of neighboring atoms. Lastly if you know, how was research conducted when developing the Manhattan Project, with regards to safety, casualties, initial testing, interest in nuclear chemistry, or expenditures? I have prior knowledge that such unstable elements are quite expensive in the modern age but how would they compare in terms of availability, value, and purity to their WWII counterparts.
ReplyDeleteHi Joey! Thanks for the question! The main test of the atom bombs was known as the Trinity test, and it was the first dentonation of a nuclear weapon to occur. The bomb dropped during this test was the Fat Man, or the plutonium implosion device. This test was conducted at a military test site in the middle of the deserts of New Mexico. There was research conducted on the area beforehand to ensure that no casualties were caused by the explosion. The total expenditures of the Manhattan Project, when inflation is taken into account, was about 30 billion dollars. The Fat Man cost more than the Little Boy, because the scientists and engineers had to develop a completely new mechanism for Fat Man. The atomic bombs killed a total of 125,000 people. It is thought that if the bombs were not dropped, and an invasion occurred, then it would have cost over 50,000 American lives and even more Japanese lives. It is also thought that it would have taken ten more years of fighting and the deployment of over one million American soldiers, to defeat Japan without the bombs.
DeleteThis topic is very interest because I didn’t know that the two bomb was design to have a different usage. The purpose of the Fat Man was to immense damage and the Little Boy was to cause casualties. What was the change made to the design so that the two bomb will have a different usage purpose? Also I was wondering, why the radioactive element use in each bomb is different from each other? Which radioactive element will release more energy when undergoing the fission reaction?
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ReplyDeleteHey what's up Mac! I like your post over Nuclear weapons in WW2, pretty cool stuff. One question I had was how many atoms nuclear bombs actually split, but after reading your post I found the answer there without actually doing any research. Pretty nice. I had no clue it was actually a chain reaction that occurs, resulting in the giant explosions we see today. Thanks for your post!
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