Page 28 - Curriculum Visions Dynamic Book

Fission: splitting the atom
Fission is the process of splitting up the core, or nucleus, of an atom into two smaller pieces.
When an atom breaks apart, each of the parts carries with it more energy than it would have in nature,
and this energy is lost as heat, radiation and particles.
It is easier to get some materials to split apart than others. Uranium is the easiest, which explains its widespread use in the nuclear industry.
When enough uranium is brought together, the release of neutrons by spontaneous decay is sufficient for some neutrons to be captured by other nuclei, splitting them and so starting a “chain reaction”. Controlling this
chain reaction controls the output of the reactor
in a nuclear power station; letting the reaction
continue at an uncontrolled rate produces
a nuclear explosion (see page 32).
Barium-142
 The chain reaction of uranium fission.
A neutron
Uranium-235
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Krypton-92