A companion Java simulation on the primary additive colors of light: red, green and blue (RGB).  The applet shows what happens when you mix RGB in pairs -- the complementary colors are produced.  Combine all three and white light is the result. The format of this simulation is the same; both are appropriate for grades 6-12.

This page is the full index of materials by the same authors on Light and Color.  It contains tutorials on electromagnetic radiation, properties of light, reflection, refraction, diffraction, human vision, light filtration, and polarization of light.  It also links to more than 25 related Java simulations.