RADIATION… is an wave that moves through space at a constant speed:  300,000,000 m/s This wave is analogous to the ripples on a pond that propagate when the pond’s surface is disturbed by a rock.  The difference is that instead of waves of water propagating through space, radiation involves waves of an electromagnetic field.
	Radiation comes in many forms... •radio waves  •microwaves  •heat from a fire  •light •Ultraviolet rays  •X-rays  •Gamma rays