Other
Mixing Mouse Tracks
This art idea is based off the children's book "Mouse Paint" by Ellen Stoll Walsh. A fun way to introduce young learners to the primary and secondary colors through simple mixing exercises.
Exploratorium
Exploratorium: Science Snacks: The Three Little Pigments
For this activity, you print different colors of the same image onto acetate, then explore the different color effects you get when they are overlaid on each other in various combinations.
Physics Classroom
The Physics Classroom: Color Addition
This tutorial on the addition of color to light discusses the primary, complimentary, and secondary colors of light.