Light as a Ray
Light travels in straight
lines, except when it doesn't. Having seen a shadow cast by some
solid object, rectilinear propagation (read: definition of a straight
line path) seems logical. But the behavior of light becomes the
focus of some attention (get used to it) when we observe those
instances when it is forced out of a straight line path. We engage
two of these phenomena, reflection and refraction, every day.
Knowledge of these optical phenomena will cause you to understand
how light behaves in your every day coming and going. For example,
we see most of the objects around us because light leaves some
source, reflects off an object, and enters the eye.The reflection
is not random but rather is well understood. Light entering the
eye is directed to the retina by a phenomenon called refraction.
The retinal image is then coded as electrical signals sent to
the brain for processing. What you will encounter in these lessons
are text pages, web sites, and in-class activities that will cause
you understand the behavior of light when it is reflected and
refracted. An attempt has been made to separate consideration
of these two phenomena, although some web sites readily combine
them. We will consider these early sites as they apply to reflection
and revisit them when we encounter refraction.
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This page was last modified by
mgosselin on 10/08/2005