Radioactive Emissions

Unstable atoms are radioactive.  If an atom is unstable it will break down to become more stable.  Its instability could be caused by having too many neutrons, not enough neutrons or just too much energy inside the nucleus.  The atom decays by releasing energy and or particles until it reaches a stable form - this is called radioactive decay.  An individual radioactive decay is random - it cannot be predicted.  There are four types of nuclear radiation: alpha, beta, gamma and beta plus.  The different types of radiation have different penetrations.  When a radioactive particle hits an atom it can knock off electrons, creating an ion, so radioactive emissions are known as ionising radiation.  Alpha, beta and gamma radiation can be fired at a variety of objects with detectors palced the other side to see whether they penetrate the object.  Alpha and beta particles have different ionising properties. What a radioactive source is used for often depends on its ionising properties.  Alpha particles are strongly positive so they can easily pull electrons off atoms.  Ionising an atom transfers  some of the energy from the alpha particle to the atom.  The alpha particle quickly ionises many atoms and loses all of its energy.  This makes it suitable for use in smoke alarms because they allow current to flow, but wont travel very far. …