> If you had 6kg of U-235 and through it forcefully on the ground it would most likely explode.
First, you mean "threw", not "through." And second, this is absolutely not true. To achieve an explosion you have to induce super-criticality with very precise timing. Otherwise the uranium will melt and become sub-critical before it explodes.
> This almost happened at Las Alamos
No, it didn't. You are almost certainly thinking of these incidents:
but those were completely different. It was a plutonium core, not uranium, and it went critical not because it was thrown forcefully to the floor, but because it was inadvertently enclosed in a neutron reflector that caused it to become critical.
>To achieve an explosion you have to induce super-criticality with very precise timing. Otherwise the uranium will melt and become sub-critical before it explodes.
True, but the complexity of the Fat Man plutonium bomb (shown in the link here) belies the simplicity of Little Boy uranium bomb.
First, you mean "threw", not "through." And second, this is absolutely not true. To achieve an explosion you have to induce super-criticality with very precise timing. Otherwise the uranium will melt and become sub-critical before it explodes.
> This almost happened at Las Alamos
No, it didn't. You are almost certainly thinking of these incidents:
http://en.wikipedia.org/wiki/Demon_core
but those were completely different. It was a plutonium core, not uranium, and it went critical not because it was thrown forcefully to the floor, but because it was inadvertently enclosed in a neutron reflector that caused it to become critical.