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Lesson 11 |
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| Radiation Facts and Myths | |
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Despite
what many people think, radiation is not a twentieth
century atomic power invented by scientists during the
Second World War. Long before humans came into life,
every one of the earth's environmental and ecological
systems was already operating on a planet immersed in
radioactivity. The oldest rocks found by geologists, the
oldest dinosaur bones discovered by archaeologists, and
the oldest stars spotted by astronomers, far though they
are from the earth, prove that this planet is a
radioactive world in a radioactive universe, and always
has been.
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The Basics of Radiation, Radioactive Decay, and Radionuclides All matter is composed of atoms, and all atoms share similar structural elements. At the center of every atom is a dense, positively-charged nucleus, comprised of positively-charged protons and neutral particles called neutrons. The nucleus is surrounded by a "cloud" of light, negatively-charged electrons that orbit the nucleus. Approximately 99.95% of any atom's mass is found in the nucleus, which is held together by the strong nuclear and electrical interactions between the protons, neutrons, and electrons. |
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| When these nuclear forces within the atom are balanced, the atom is stable and all the subatomic parts remain where they are. If the nuclear forces within the atom are not balanced, the atom will become unstable, and will begin to eject subatomic particles or waves of energy to regain stability. Radioactivity (or radioactive decay) is the phenomenon where energy (radiation) is emitted from the nucleus of an unstable atom while it gains stability. Energy can be emitted in the form of particles or in the form of pure energy. |
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