Little Boy was dropped over Hiroshima while Fat Man was dropped over Nagasaki. Both resulted in devastating effects. However, the way they functioned differed.
Little Boy used a gun-type design - whereby, an amount of U-235 was fired at another, creating a critical mass and setting off a fission chain reaction. On the other hand, Fat Man was created with conventional explosives around a Pu-239 core, which squeezed the Plutonium, increasing its density. This allowed the core to reach critical mass for a fission chain reaction to occur. The explosives were ignited to detonate the bomb |