Radiation * Emission of energy from an atom and the transmission of this energy through space. * Energy propagated in a material medium or space. * Energy in transit.
What are the types of radiation? * Radiation is of two general types in our environment. * They are called non-ionizing and ionizing.
Ionization * the energy transferred to the electrons causes them to be pulled away or removed from an atom entirely. * The result is the formation of an ion pair. * The ion pair consists of a negatively-charged free electron and a positively -charged atom.
Excitation * Process occurs when an inner electron of an atom receives enough energy to allow it to move into an excited state at a higher energy level. * However, this transfer is only temporary. * Electron soon returns to its original energy level by re-emitting the energy gained as electromagnetic radiation. * A familiar example of excitation is the emission of light in the glass tubes in an advertising sign, commonly known as “neon signs”.
Non-Ionizing Radiation * Non-ionizing radiation exists in various forms. * Some are detected by our senses while other forms are recognized through special instruments that convert this type of radiation into signals that our senses can recognize. * Familiar examples * Radio waves which carry information and entertainment through radio and television. * Microwaves which are used in microwave ovens and to transmit cellular telephone messages. * Infrared rays which provide energy in the form of heat. * Visible light which we can see * Ultraviolet rays from the sun which can provide a good suntan
Ionizing Radiation * Radiation that exists in our environment. * Unlike infrared (heat) or visible light, it is undetected by any of our physical senses. * Can be detected it with simple radiation detection instruments. * Occurs