6A42.20-Refraction Tank and Laser

6a4220refraction rank and laser

Description: This demonstration shows how light from a laser will refract at the interface of two materials with different refractive indexes.


  • Small plastic tank
  • Mounted Laser
  • Portable stand
  • S clamp
  • Compressed air
  • Milk powder
  • Water

Setup Procedure:

  1. Fill the take up with water.
  2. Add a little milk powder to the water. Mix it in.
  3. Attach the laser to the portable stand as shown in the picture.
  4. Angle the laser to enter the water at roughly a 45 degree angle.

Demonstration Procedure:

  1. Turn on the laser.
  2. Turn off the lights.
  3. Spray the compressed air just above the top of the plastic tank. You can also use chalk dust.
  4. Note the angle of incidence and the angle of refraction. They are not the same.
  5. This is because light bends as it travels from an air to water medium.
  6. When finished, turn off the laser.

Laser Light Laser Light
Do not stare at the laser beam. Do not point the laser at students.

Note: This picture is time elapsed. In person, the beam will not be as bright.