|The Hiroshima and Nagasaki bombs|
The energy of the plutonium bomb dropped on Nagasaki, nicknamed FAT Man, was estimated at 21 kilotons of TNT. A huge fireball was created immediately after the explosion accompanied by a wave of heat and extremely high radioactivity. The strong expansion of the air around the epicenter generated a blast. It was estimated that the energy of the explosion was divided as follows: 35% as heat, 50% for the blast and 15% in the form of radioactive energy.