Little Boy and Fat Man and how they work

The end result of the Manhattan Project is very well known and is looked down upon as it was a huge loss of lives. Einstein said in his later years that sending the famous letter to President Roosevelt was his life's biggest regret, no doubt everyone knew the reason.

Little Boy

On August 6, 1945 the atomic bomb known as Little Boy was dropped on Hiroshima. Little Boy unlike the other atomic bomb Fat Man, Little Boy was filled with 64kg of U-235 and less than a kilogram would undergo nuclear fission.The uranium inside was enriched at Oak Ridge and then sent to Los Alamos. The design used was the gun method where a cylinder shaped object with rings of U-235 on the front was fired down a barrel into a U-235 target. When the projectile hits the target, the target splits in two because a neutron upsets balance in the atom. The two new atoms then release a neutron which does the same to other atoms. This process continues and is thus a chain reaction.

Fat Man

Fat Man was the other atomic bomb dropped on Nagasaki on August 9, 1945. It is a very different type of bomb compared to the previous. It is an implosion type nuclear weapon with a Plutonium core. Unlike Little Boy it had been tested a month earlier and created a significantly bigger explosion. This explosion begins when the conventional explosives set off. (see diagram). This occurs equally throughout the sphere and hits and compresses the Pu-239 into a neutron initiator. The neutrons in the middle split the Pu-239 atoms and a fission chain reaction begins.