ch27_pswc

__ Early Concepts of light __ ** __The speed of light__ > extra time measued Materials which absorbe light witout re-emmitting it are called opaque. when light goes in the enrgy will be transformed into heat. __Electromagnetic waves __ As you can tell from the diagram above. The waves get smaller and have a higher frequency.
 * __LIGHT__
 * Ancient Greek philosophers thought that light consisted of many particles.
 * Huygens was the first scientist that believed that light was in fact a wave.
 * The light theory was supposted by the fact that light seemed to move in a straight line instead of spreading out like a wave.
 * Scientist now agree that light has a dual nature, part particle and part wave.
 * Speed of Light = __extra distance traveled__


 * Shadows **
 * A shadow is defined as a thin beam of light often called a ray. any beam of light, no matter how wide can be tought of as made of a bundle of rays.
 * A shadow is formed where light rays canot reach.
 * Sharp shadows are produced by a small light source
 * A foggy shadow is produced by a large light source
 * A total shoawos is called an umbra and a partial shadow is a penumbra



Used in sunglasses to block out rays of sun Light will pas through a pair of sunglasses when their polarazation axes are aligned, but not when they are crossed at right angles. Light can also be polarized by reflecting off of a surface, if light bounces off of a horizontal surface at a low angle it will bevome horizontally polirized. Polirized light is used to produce 3D images. Two projectors are used at one time, one projector has a horizontal filter and the other has a vertical lens filter.
 * Polarization **