I found this little light box that changes colors from red to blue to green at the Dollar Tree.
I made some color cards from some left over tissue paper squares and contact paper. If I were to make them again, I would use one sheet of color instead of squares.
When you hold the color cards over the light you can see some mixing of colors. Worth $1.
We also used the cards with a flashlight.
I'm always jealous when I see people with a light table. But thanks to Deborah at Teach Preschool, we can all afford one.
I will be making my own version of the light table.