Supplies:paper / leaf coloring pages
foil muffin pan
covered foil cake pan(s)
Print out some leaf coloring pages and have the kids cut out their own leaf shape. Sometimes I cut random leaf shapes freehand ahead of time for them, especially with preschoolers.
While they're cutting, you can ready the paints. In a foil muffin pan mix your colors. I usually do yellow, orange, red and brown. I took these pics after our paints had dried, but you'll get the idea. Be sure you're using washable paints! [brown is made by mixing all 3 primary colors: red, yellow, blue.] Drop a marble in each muffin cup and roll it around until it's full of paint:
Put the child's paper leaf in the bottom of the cake pan. They can pick up one colored marble at a time and drop it right on the leaf:
Cover the pan and shake it from side to side:
put in a marble of a different color. Repeat until they like how their leaf looks!