Remember using kaleidoscopes as a kid? I LOVED them! This project was referred to me by a teacher here at school, and I love it. The kids were really interested and engaged throughout the entire class period. I had them trace circles with a sharpie because I wanted this to be a 1-day lesson. If you wanted to extend it, have them stamp circles using black paint and then when the paint dries, you can have them use watercolors to fill-in the areas. Another idea is to have the students experiment in color mixing where they paint the entire circle a solid color and then when it overlaps with another circle, they can see what new color is made by overlapping the colors. Of course I thought of this technique AFTER I finished the lesson, but good to know for next time! Good luck!