The Manhattan Project, An Interactive History Home The Manhattan Project, An Interactive History Home Department of Energy Home Office of History and Heritage Resources Home DOEHome
J.R. Oppenheimer and General Groves
Events People Places Processes Science Resources

Time Periods

1890s-1939:
Atomic Discoveries

1939-1942:
Early
Government Support

1942:
Difficult
Choices

1942-1944:
The Uranium
Path to
the Bomb

1942-1944:
The Plutonium
Path to
the Bomb

1942-1945:
Bringing It All Together

1945:
Dawn of the
Atomic Era

1945-present:
Postscript --
The Nuclear Age

Excerpt from the comic book "Adventures Inside the Atom." Click on this image or visit the "Library" to view the whole comic book.ATOMIC DISCOVERIES
(1890s-1939)
Events

Philosophers of Ancient Greece reasoned that all matter in the universe must be composed of fundamental, unchangeable, and indivisible objects, which they called "atoma" ("ατoµα"). The exact nature of these atoms remained elusive, however, despite centuries of attempts by alchemists to create a "philosopher's stone" that could transmute atoms of lead to gold, prove the Greeks wrong, and make its inventors Modern model of an atomvery rich.  It was only in the late 1890s and the early twentieth-century that this view of a solid atom, bouncing around the universe like a billiard ball, was replaced by an atom that resembled more a miniature solar system, its electrons orbiting around a small nucleus.  Explorations into the nature of the atom from 1919 to 1932 confirmed this new model, especially with Ernest Rutherford's 1919 success in finally transmuting an atom of one substance into another and with James Chadwick's 1932 discovery of the elusive final basic particle of the atom, the neutron.  From 1932 to 1938, scientists around the world learned a great deal more about atoms, primarily by bombarding the nuclei of atoms and using a variety of particle accelerators.  In 1938, word came from Berlin of the most startling result of them all: the nucleus of an atom could actually be split in two, or "fissioned."  This breakthrough was quickly confirmed in the United States and elsewhere.  According to the theories of Albert Einstein, the fission of an atom should result in a release of energy.  An "atomic bomb" was now no longer just science fiction -- it was a distinct possibility.  

FissionTo learn more about any of these events associated with the early years of atomic research, choose a web page from the menu below.  To continue with a quick overview of the Manhattan Project, jump ahead to the description of "Early Government Support" provided uranium research from 1939-1942.    

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Sources and notes for this page.

The text for this page is original to the Department of Energy's Office of History and Heritage Resources. The meaning of the word "atoma" is from the entry on "Democritus" in The Concise Oxford Companion to Classical Literature, edited by M. C. Howatson and Ian Chilvers (New York: Oxford University Press, 1993), 167-168.  Click here for more information on the comic book image.  The atom graphic is a combination of graphics that were originally produced by the Washington State Department of Health (the nucleus) and the Environmental Protection Agency (everything else); the combination of the two graphics, the labels, and other customizations, are original to the Department of Energy's Office of History and Heritage Resources. The fission graphic is adapted from a graphic originally produced by the Washington State Department of Health; the modifications are original to the Department of Energy's Office of History and Heritage Resources.

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