How does a atmic bom blow up?

Answer 1

It's "Atomic Bomb." anyways,

An Atomic Bomb works by initiating a nuclear chain reaction, which releases a huge amount of energy relative to conventional explosives. Per unit volume, an atom bomb may be millions or billions of times more powerful than TNT.

Answer 2

An atomic bomb detonates when a critical mass of fissile material, such as uranium or plutonium, is brought together rapidly to start a chain reaction of nuclear fission. This chain reaction releases an immense amount of energy in the form of heat, light, and radiation, resulting in a highly destructive explosion.