TIMELINE of the Atomic Bomb. 1942 May - Heisenberg and Do pel observe the first multiplication of neutrons. December 2 - First nuclear chain reaction at Chicago's Stagg Field by Fermi. 1943 March 15 - Oppenheimer moves the bomb development to Los Alamos.
1944 August 26 - Bohr presents his memorandum on intentional control of nuclear weapons to Roosevelt. 1945 January 20 - First Uranium-235 separated at Oak Ridge. July 16 - U. S. explodes first atomic bomb, the Trinity test, at Alamogordo. August 6, 9 - Atomic bombs dropped on Hiroshima and Nagasaki.
(Blow) The atomic bomb gets its energy from fission (splitting) of the nuclei (core) of uranium or plutonium atoms. Albert Einstein explained how the fission of heavy atoms could produce energy released as dangerously high levels of heat and radiation. He published his theory in 1905 which is the well-known equation E = m c-squared. This states that a given mass (m), is associated with an amount of energy (E), equal to this mass multiplied by the square of the speed of light (c). (Blow) A very small amount of matter is equivalent to a vast amount of energy. For example, 1 kg of matter converted completely into energy would be equivalent to the energy released by exploding 22 megatons of TNT.
The neutron is the most effective particle to cause uranium fission. Only one neutron is needed to split an atom. When the atom fissions (splits), it splits into two smaller atoms which are most always radioactive and releases an enormous amount of energy and two or three neutrons. The neutrons released could then possibly hit other nuclei of uranium, which causes them to split in the same fashion. This is a chain reaction (a series of fissions). A baseball made of plutonium produced an explosion equal to 20, 000 tons of TNT.
Research on atomic bombs was begun around the same time in several countries, including Germany, but in the United States, the actual building of an atomic bomb was already underway by 1942 under the code name 'Manhattan Project.' The project was carried out in extreme secrecy using a large amount of the national budget.