If we add a color to a jar of water it will get colored. If we pour that water down, the color, which is dissolved in the water, will also go along with it. This science fair project is to experiment the same but using light!!
- A small glass jar with plastic lid.
- Thick insulation tape.
- Some Water
- A flash light.
- First, we should make two small holes in the cap of the jar. In order to help water steadily flow out through any one of the holes, the holes should made in such a way that it should be diagonally opposite to each other. (The water will flow out through one hole and the other hole will let air in.)
- Attach the flashlight to the bottom of the glass jar using insulation tape so that when the flash light is switched on the light goes through the jar. Also make the walls of the jar opaque using the insulation tape so that no light other than that from the flash light enters the jar.
- Now fill the jar with water and tighten the cap.
- Switch on the flash light.
- Slowly allow a thin stream of water to pass through one of the holes in the cap.
What do you see?
Due to total internal reflection, the light will be captured within the stream. We cannot see the stream from the side. The light will only be visible when the stream breaks up or hits something.