Nuclear Museum Logo
Nuclear Museum Logo

National Museum of Nuclear Science & History

“Little Boy” Atomic Bomb

Ranger Home > Los Alamos Innovations > “Little Boy” Atomic Bomb

The Tech Area
Uranium Gun-Type Bomb
The Gun Site
Read Transcript
Quick Fact:
Manhattan Project scientists designed the world's first atomic bombs: a uranium gun-type bomb, "Little Boy" and a plutonium implosion bomb, "Fat Man." The US dropped the Little Boy bomb on Hiroshima on August 6, 1945. Between 90,000 and 166,000 people are believed to have died from the bomb in the four-month period following the explosion. The Fat Man bomb, dropped on Nagasaki on August 9, 1945, killed about 80,000 Japanese by the end of 1945. Historians continue to debate the role of the atomic bombs in ending World War II.