Nuclear Radiation | GCSE Physics | Doodle Science
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Script:
Background radiation is all around us. Some of it comes from natural sources and some comes from artificial sources. Natural sources include cosmic rays, radiation from rocks and soil released by the radon gas and living things that absorb the radioactive materials and pass it up the food chain. However, human activity has added to background radiation by creating and using artificial sources of radiation. These include radioactive waste from nuclear power stations, radioactive fallout from nuclear weapons testing and medical x-rays.
There are three main types of radiation emitted from radioactive atoms. These are alpha, beta and gamma radiation. Alpha radiation consists of alpha particles. An alpha particle is identical to the helium atom but without the electrons. So 2 protons and 2 neutrons are emitted from the nucleus reducing the atomic number by 2 and the mass number by 4. Beta radiation consists of a high-energy electron emitted from the nucleus. These electrons have not come from the electron shells or energy levels around the nucleus. Instead, they form when a neutron splits into a proton and an electron and the electron then shoots out of the nucleus at high speed. Gamma radiation is a very short wavelength on the EM spectrum. It can occur when there is energy left over after alpha or beta radiation has been emitted.
Alpha radiation is the least penetrating. It can be absorbed by a thin sheet of paper. Beta radiation can penetrate air and paper. It can be stopped with a thin sheet of aluminium. Finally, gamma radiation is the most penetrating. Even small level can penetrate air, paper or thin metal. Higher levels can only be stopped by many centimetres of lead or many metres of concrete.