Atomic Bomb, powerful explosive nuclear weapon fueled by the splitting, or fission, of the nuclei of specific isotopes of uranium or plutonium in a chain reaction. The strength of the explosion created by an atomic bomb is on the order of the strength of the explosion that would be created by thousands of tons of TNT An atomic bomb must provide enough mass of plutonium or uranium to reach critical mass, the mass at which …showed first 75 words of 1233 total…

…showed last 75 words of 1233 total…ven more powerful weapon triggered by a fission reaction but fueled by the fusion of hydrogen. The United States detonated the first hydrogen bomb in a test on Enewetak Atoll, in a remote region of the Pacific Ocean, on November 1, 1952. Its explosive force was about 500 times greater than the Hiroshima or Nagasaki bombs. The Union of Soviet Socialist Republics (USSR) detonated its first hydrogen bomb on August 12, 1953. Today, most nuclear weapons are fusion thermonuclear devices.