On August 6, 1945, a 10-foot-long (3 meters) bomb fell from the sky over the Japanese city of Hiroshima.
Less than a minute later, everything within a mile of the bomb's detonation was obliterated.
Old manuscripts show that bismuth was often confused with lead, tin, antimony, or even silver. An alloy is made by melting and mixing two or more metals.Nevertheless it generates 0.1 watts/tonne as decay heat and this is enough to warm the Earth's core. The nucleus of the U-235 atom comprises 92 protons and 143 neutrons (92 143 = 235).When the nucleus of a U-235 atom captures a moving neutron it splits in two (fissions) and releases some energy in the form of heat, also two or three additional neutrons are thrown off.Natural uranium as found in the Earth's crust is a mixture largely of two isotopes: uranium-238 (U-238), accounting for 99.3% and uranium-235 (U-235) about 0.7%.The isotope U-235 is important because under certain conditions it can readily be split, yielding a lot of energy.