Experiment with different sizes of beams and flashlights and document what you see. Put can or other object in the middle of the tank. Shine light through tank and observe what happens when beam passes through water and hits object. Next, place dark sheets of paper along the sides and end of the tank. Focus a beam on the far end of the tank and observe how light shined in at one end hits mostly, but not entirely, on the other end.
Refraction causes some light waves to bend and pass through the side walls.
Shine light through air in tank. Share what we have learned and observed. Evaluation Have students demonstrate, draw, or tell how light waves travel through air, water, paper, glass, hands, etc. Listen for evidence that they understand reflection and refraction. Have them record information about their observations.