description: Understanding RadiationNatural and Man-made Sources of RadiationWe are constantly exposed to radiation, whether cosmicradiation from outer space or radiation fromradioactive elements in the earth’s rocks and soil.These sources contribute to the natural backgroundradiation that has always been around us. But there arealso man-made sources of radiation, such as medicaland dental x-rays, household smoke detectors, andmaterials released from nuclear and coal-firedpower plants.All matter in the universe is made of atoms, andradiation comes from the activity of these tinyparticles. Atoms are made up of even smallerparticles called protons, neutrons, and electrons. Thearrangement of these particles distinguishes one atomfrom another.
language: English
title: Understanding Radiation
publisher: U.S. Government and www.survivalebooks.com