Fat Man

Featured Artifact

Displayed at the Museum is an exact replica of Fat Man, the bomb dropped on Nagasaki on August 9, 1945. This type of bomb was tested at Trinity Site in southern New Mexico on July 16, 1945.

Fat Man, which was designed and built at Los Alamos, was an implosion-type bomb. It consisted of a core of plutonium-239 surrounded by explosive chemicals. When the explosives were detonated properly, the shock compressed the fissionable material at the core, increasing its density and making it supercritical, or able to sustain an explosive nuclear reaction.

Weight — 10,800 pounds
Length — 128 inches
Diameter — 60 inches
Yield — equivalent to 21,000 tons of TNT
Fissile material — Plutonium-239

Fat Man picture