Atoms are made of three types of sub-atomic particle: neutrons and protons in the nucleus and electrons orbiting the nucleus. Some materials are radioactive because the nucleus of each atom is unstable and gives out nuclear radiation in the form of alpha particles, beta particles or gamma rays. Particle | Relative mass | Relative charge | Proton | 1 | +1 | Neutron | 1 | 0 | Electron | Almost zero | -1 |
Types Of Radiation
There are three types of radiation; Alpha, Beta and Gamma. Some isotopes of atoms can be unstable.
They may have: Too much energy or the wrong number of particles in the nucleus. These are called radioisotopes. To make themselves more stable, they throw out particles and/or energy from the nucleus. We call this process 'radioactive decay'. The atom is also said to disintegrate. The atom left behind is different from the original atom. The particles and energy given out are what we call 'radiation' or 'radioactive emissions'.
Background Radiation
There is a certain amount of radiation around us all the time. There always has been since the beginning of the Earth. Background radiation comes from a huge number of sources. In most areas, Background radiation is safe. It is at such a low level that it doesn't harm you. However, some areas of the country have a higher level of background radiation than others because the rocks near the surface contain more radioactive isotopes (Cornwall).
Half Life
We use the half-life of a substance to tell us which substances decay the quickest.
Half-life - is the time it takes for half of
