There are a few different ways that an atomic bomb can be built. The two main elements of atomic bomb is plutonium and uranium. The bombs would use isotopes uranium 235 and plutonium 239. Fat Man, which was the nuclear bomb dropped on Nagasaki, used plutonium fission with an implosion design. Little Boy, which was the nuclear bomb dropped on Hiroshima, used uranium instead of plutonium. Little boy had most of its weight come from the uranium that was inside it. About 80% of enriched uranium 235 was compacted into the bomb and sitting by itself was twice critical mass. That 80% weighed in at 112 pounds and it is estimated that less that 1% of the uranium used in Little Boy was actually used. The rest of the uranium 235 was eviscerated. …show more content…
Fat man could not use the same design as this gun-type design from Little Boy. From Fat Man using plutonium 239, the gun-type design could not be used for this version. The original design of this bomb was to use plutonium 240 instead of plutonium 239, but from plutonium 240’s higher fission rate, atoms from plutonium 240 would start to undergo fission before the bomb would be set off and from this it would lower the energy output of the bomb. So from this, scientist decided to use plutonium 239 from it being slightly more stable. Scientists then had conventional explosives put around a plutonium sphere that would explode causing the plutonium to collide at a very fast speed at each other causing the fission to be more instantaneous and a little bit more controlled. This was called an implosion design because the explosives inside the bomb were pointed towards the plutonium causing it to collide to produce more energy from the fission and from this would cause the