Here's a fun website to learn more about colors and lights: The Physics Classroom.
Mixing light is different than paint. For example red + green = yellow (instead of brownish) and blue + red = magenta (instead of purple)
White = all primary light colors (R+G+B)
Black = all primary paint colors (R+B+Y)
Mixing light is additive where as mixing paint is subtractive.
Mix different colors of paint
Shine/mix similar colors of light
Compare and contrast
Instead of flashlights, we also have small LED lights of red, blue, and green. This seems to be less of a hassle than taping cellophane to flashlights. Big J bought them a few years ago for a Cub Scout activity about photography and light. Just remember not to stare into LED lights.