The Little Boy type of bomb, which was dropped on Hiroshima, had a much simpler design than the Fat Man model that had been tested at Trinity. The atomic bomb, nicknamed Little Boy, is seen before being loaded into Enola Gay's bomb bay on Tinian.
Scientists at Los Alamos were not entirely confident in the in the plutonium bomb design, so they scheduled the Trinity test. This would compress the plutonium sphere to a critical density and set off a nuclear chain-reaction. bomb containing a sphere of the metal plutonium 239, it was surrounded by blocks of high explosives that were designed to produce a highly accurate and symmetrical implosion. Fat Man, which was dropped on Nagasaki, was the more complex of the two. The Manhattan Project produced two different types of atomic bombs, code-named Fat Man and Little Boy.
