Oe-2 Light Trapped in a Stream of Water


To demonstrate how a beam of water may be guided by total internal reflection to follow a curved path in a spout of water.


  • Laser
  • Fish tank
  • Large beaker
  • Labjack

Water Light Pipe Light Trapped in Water Stream

Light Trapped in Water Stream Setup and Diagram.


This intriguing demonstration of total internal reflection shows how light may be trapped and guided by an unbroken stream of water flowing from a glass jar. A laser beam is initially aimed at the back of a small stopper, through the opposite side of the glass jar. When the stopper is removed the beam is guided by the stream of water and shows up as a brilliant spot where the stream lands. The effect is made visible to a large audience by catching the stream in a large fish tank and inserting a sloping white screen onto which the stream of water splashes.