Purpose: To demonstrate reflection, refraction, dispersion, total internal reflection performed with a single light source.

The apparatus consists of a 120 cm x 120 cm sheet of plywood painted black, on which are mounted one or two light sources which produce an intense, well-collimated light beam whose position is visible to a large audience. Examples of single-ray and a double-ray demonstrations are shown below:

The apparatus can be set up in any classroom which can be made reasonably dark. With one light source, you can show Snell's Law and total internal reflection, and an excellent spectrum can be produced with the glass prism. With two light sources, the action of concave/convex mirrors and lenses, or combinations thereof, can be demonstrated. For more details, see the folder Blackboard Optics.

With two light sources, you can demonstrate the action of lenses and mirrors.

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