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 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.