A plastic straw is sitting in a clear glass filled halfway with sparkling water (n=1.40). The angle between the straw and the surface of the sparkling water is 35¬°.
(8) What does the angle between the straw and the normal appear to be in the sparkling water?
This problem involves Snell's Law. Note that light is traveling from the sparkling water to the air to the observer, so that n=1.40. The angle is 55¬° since the angle between the straw and the sparkling water is 35¬° (recall that the required angle is measured from the normal). Solving for gives:
