Colour Mixing Box

This unit contains three coloured light sources (red, green and blue) projected onto screen in overlapping circles. The unit is self-contained, meaning no setup is required, and can be used comfortably by 2-3 pupils at time.
The brightness of each light can be controlled independently, allowing any combination of the three. This allows the demonstration of composition of any colour using just the primary colours.
Requires 3 x AA batteries.