[Krafty123]

Wasn't it an implosion device? IE the center is fissionable U-235 (85 pounds) and around it is U-238 (85 pounds). Explosives go off around the outside, pushing the U-238 into the U-235 & making it dense enough to start a chain reaction.

[MetalMan]

The one dropped on Hiroshima was a uranium bomb. It had a gun inside which fired a urnanium projectile at some more uranium, which started the chain reaction. The bomb dropped on Nakasagi(sp?) was an implosion device, which used plutonium.

I think.. I could be mistaken, but 90% sure that's accurate.

[cpdiii]

NO

The Hiroshima bomb was basically a cannon barrel with two sub critical U235 slugs in it. One was fired into the other making a critical mass and the it went BOOOOOM.

The bomb dropped on Nagasaki was a plutonium sphere with explosives around it. When fired it compressed the sphere into a critical mass and then in went BOOOOOOM.