I love this system for introducing the color wheel and color mixing to young students. I think the idea came from Deep Space Sparkle and it works so well. With a sharpie draw three circles on the plate. This is where kids will mix the secondary colors. In the in-between places drop a dab of red, yellow, and blue paint. The circles give the kids a visual cue where to mix their paint so everything ends up neat and tidy.
We used our newly mixed colors to paint us some RAINBOW fish.