The Manhattan Project
~A top secret U.S.
oSecret program from 1942-1946 in the U.S.
focusing on building the first atomic bomb
oEven Harry S. Truman did not know about the
project until Roosevelt’s death in 1945.
oto develop the
before Germany or
oIn order to end
oTo show it off
to the world
The race was on…
They were able to work toward building the
atomic bomb through achievements in the area
of nuclear physics, including the discovery of
fission. They used the idea of fission, the
separation of an atom, to build their atomic
oMany scientists were involved in the Manhattan
Project such as Albert Einstein, Enrico Fermi, and
oOppenheimer was in charge of the project along
with General Leslie R. Groves.
oThe Nazis made the mistake of exiling their
Jewish scientists, and they then went to the U.S.
and helped them build nuclear weapons.
Einstein: Involvement in
Einstein came from Germany to
He wrote a letter to President
Roosevelt that was received on
August 2, 1939.
Warned him of Germany’s advances
within nuclear physics and research
involving the atomic bomb
Warned of attempts at building
Over 30 different sites but the main 3 centers for
the Manhattan Project were:
Los Alamos, New Mexico (assembled nuclear
Oak Ridge, Tennessee (produced uranium-
Hanford, Washington (produced weapons-
The Atomic Bombs
The Scientists for the Manhattan
Project built a test bomb and the two
bombs that were dropped in Japan.
“Gadget” which was the test bomb and
was plutonium based
“Little Boy” which was dropped in
Hiroshima and was uranium based
“Fat Man” which was dropped in
Nagasaki and was plutonium based
Some Key Events
May 12, 1942~Roosevelt signs an order to
create the Manhattan Project
April, 1943~ Bomb design begins in Los
1944~Uranium, gun-style bomb is
determined to be reliable
July 16, 1945~ experience the first atomic
bomb during a trial
August 6, 1945~Little Boy was dropped
August 9, 1945~Fat Man was dropped
The scientists had opposing views on
the use of the atomic bomb.
Some felt that it should not be
used for ethical reasons.
Others felt that it needed to be
used as a defense mechanism
However, the decision was not up to
them. It was left to Harry S.
The Manhattan It led to massive
Project allowed death and a
scientists to make terrible aftermath
new discoveries of WWII.
about the atom.
It became the
It allowed the
U.S. to become type of warfare
one of the leading known to mankind.
nations in the
American Nation in the Modern Era. New York: Holt,
Rinehart and Winston, 2005.
quot;The Manhattan Project: An Interactive
History.quot; Department of Energy - CFO Home. 20 Apr.
quot;Key Issues: Nuclear Weapons: History: Pre Cold War:
Manhattan Project.quot; Nuclear Files - From nuclear
proliferation to nuclear testing, from Hiroshima to North
Korea, Nuclear Files offers the A to Z on nuclear issues. 26
Apr. 2009. <http://www.nuclearfiles.org/menu/key-
quot;The Manhattan Project.quot; Travel and History. 26 Apr.