PURPOSE: To demonstrate a medium with a continually varying index of refraction.
DESCRIPTION: Placing sugar along the bottom of a long, narrow water tank, as the sugar dissolves it creates an index of refraction gradient with the greater index of refraction nearer the bottom of the tank. A laser beam bends continuously in t he sugar solution and reflects off the bottom of the tank, as shown in the photograph. Observation of the path of the laser beam is enhanced by adding a pinch of powdered coffee creamer.
SUGGESTIONS:
EQUIPMENT: Laser with water tank and sugar.
SETUP TIME: 12 hours. (This demonstration requires overnight to prepare the sugar solution.)