Anything that is not at absolute zero (0 K, i.e. everything) willemit radiant energy. Radiant energy is caused by electronconfiguration changes within the substance, whether i
…t be liquid,solid, or gas. It is transported between objects viaelectromagnetic waves, which means that it does not require anymatter between the two objects in order to transfer energy.Examples would be the sun emitting radiation to the earth throughspace, or a radio antenna emitting radiation to your car's stereo.There doesn't need to be air between the antenna and your car inorder for you to pick up a signal. Radiate Energy can be carried by light too! Radiation Transfers Energy Energy can be transferred even though there are no particles totransfer the energy. This type of energy transfer is calledradiation. Energy that is transferred in this way is called radiantenergy or electromagnetic radiation (EMR for short). Radiant energy travels in waves (much like a tsunami). These waves can travel through space, air, glass and many othermaterials. There are different forms of EMR, including radio waves,microwaves, visible light and X-rays. If the energy source is a warm object, like the sun, some of thethermal energy is transferred as a type of EMR called infraredradiation (IR) or 'heat radiation'. Properties (characteristics) of Radiant Energy are: Waves of radiant energy can travel in a vacuum. All waves travel, across empty space, at an extremely high speed(300 Million m/s). Radiant energy travels in a straight line. they behave like waves they can be absorbed and reflected by objects All kinds of radiant energy interact with matter: Reflection occurs if the energy cannot penetrate the surface of thematerial it comes into contact with. Absorption occurs if the energy penetrates part way into theobject. Transmission occurs if the energy penetrates completely, passingthrough the object with no absorption of energy. Absorbing / Emitting Energy Dull dark objects absorb radiant energy when they arecool, and emit radiant energy when they are hot. (eg. asphaltsidewalk) Light, shiny objects or surfaces do not absorb radiant energyreadily and do not emit radiant energy readily. (eq. ice surface) Radiant emission of energy from the body depends on surface area(smaller areas help to retain heat, whereas, larger areas radiateheat). This is evident in the adaptations of many species ofanimals who have successfully adapted to their environments.(desertanimals - eg. Fox p. 140) (killer whales-The killer whale'sfusiform body shape and reduced limb size decreases the amount ofsurface area exposed to the external environment. This helps killerwhales conserve body heat.) The polar bear has black skin to absorbradiant energy with transparent hair that transmitts ultravioletradiation to the skin. Most radiation (82%) people are exposed, to comes from naturalsources. By far the largest source is radon, an odorless, colorlessgas given off by natural radium in the Earth's crust. Artificialradiation, mostly from medical uses and consumer products, accountsfor about eighteen percent of our total exposure. The nuclearindustry is responsible for less than one percent. Radiation can be detected, measured and controlled. The measurement of radiation is by the amount ofradioactivity present or the amount of radiant energy given off. Radiation in the Environment Radiation is a natural part of our environment. Humanshave always lived on earth in the presence of radiation. Naturalradiation reaches earth from outer space and continuously radiatesfrom the rocks, soil, and water on the earth. Background radiationis that which is naturally and inevitably present in ourenvironment. Levels of this can vary greatly. People living ingranite areas or on mineraliscd sands receive more terrestrialradiation than others, while people living or working at highaltitudes receive more cosmic radiation. A lot of our naturalexposure is due to radon. a gas which seeps from the earth's crustand is present in the air we breathe. (MORE) 
