Interesting Refraction Phenomena Most of our discussion of
refraction in this unit has pertained to the refraction of light
at a distinct boundary. As light is transmitted across the
boundary from one material to another, there is a change in
speed, which causes a change in direction of the light wave. The
boundaries that we have been focusing on have been distinct
interfaces between two recognizably different materials. The
boundary between the glass of a fish tank and the surrounding
air or the boundary between the water in a pool and the
surrounding air are examples of distinct interfaces between two
recognizably different materials. It has been mentioned in our
discussion that the refraction or bending of light occurs at the
boundary between two materials; and once a light wave has
crossed the boundary it travels in a straight line. The
discussion has presumed that the medium is a uniform medium. A
uniform medium is a medium whose optical density is everywhere
the same within the medium. A uniform medium