Three types of radiation are given off by naturally occurring radioactive compounds. These types of radiation were given the names of the first three letters of the Greek alphabet. alpha, beta and gamma.
Alpha- release of an alpha particle from a nucleus. It consist of two protons and two neutrons. They are identical to the nucleus of a helium atom. Large radioactive nuclei give off alpha particles to become nuclei of atoms of different elements. Alpha have the greatest charge and mass. They can travel 7cm through air, and can be stopped by paper or clothing. (Welch, 2003)
Beta- release of a beta particle from a nucleus. Beta can be either an electron or a positron. A neutron breaks into a proton and an electron. The nucleus than becomes the nucleus of a different element. This is very similar to alpha particles. Beta has a 1- or 1+ charge and almost no mass. They are more penetrating than alpha particles, and travel about 1m through air, but are stopped by 3mm of aluminum. (Welch, 2003)
Gamma- the release of gamma rays from a nucleus. This occurs after alpha or beta as the particles in the nucleus shift to a more stable arrangement. This doesn't cause one element to change into another. Gamma has no charge or mass and are the most penetrating. They are blocked by very dense, thick materials, such as a few cm. of lead, or a few meters of concrete. Radiation can also be used for positive things just as well as negative things. Radioactive isotopes can help detect defects in structures. Radiation is use to test the thickness of metal sheets just as they are made. Radioactive isotopes can also determine the age of objects. Now you know that radiation can be used for good things just as it can be used for bad things. (Welch, 2003)
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