PURPOSE: To demonstrate the total internal reflection of
a laser beam in a water jet.
DESCRIPTION: A clear water bottle with a hole in the side is filled with
water. A laser is aligned so that the beam is centered in the hole. When the
water leaves the container several internal reflections of the laser beam are clearly
visible. The overall effect can be easily seen throughout the lecture hall as
the lsaer beam bends inside the falling water.
A great gag is as follows: Put a little red light into the bucket after doing the
experiment. After the
experiment is complete, insert the red lamp into the bucket so that it is dimly red in
color. Point out
that some of the laser light remains in the water.
EQUIPMENT: Laser, water bottle with hole, bucket.
Updated by Jun Qi in 3/22/2000