Atomic energy is the source of power for both nuclear reactors and nuclear weapons. This energy comes from the splitting (fission) or joining (fusion) of atoms. To understand the source of this energy, one must first understand the atom.
An atom is the smallest particle of an element that has the properties characterizing that element. The theory of an atomic nucleus was developed by Sir Ernest Rutherford in 1911 and was complemented by the theory of atomic structure by Neils Bohr in 1913. Understanding the atom continues to be a focus of many scientists.
