Try this experiment from The Everything Kids' Science Experiment.
Where do leaves get their colors?
3-5 leaves from the same tree
Nail polish remover (acetone needed)
1. Tear leaves into small pieces.
2. Place pieces in the bottom of clear container and mash them together with a spoon.
3. Add several teaspoons of nail polish remover to the leaf mush. Be sure the mush is totally covered.
4. Position coffee filter over the container. It should rest in the liquid but not touch the leaves.
5. Let it sit for a few hours, observe!
What we observed? We saw the nail polish turn green. It worked its way up the coffee filter looking clear. Near the bottom of the coffee filter we could see a green color. After that, we could see a yellow color.
Our new question? What color would we see with leaves from a red maple tree?
What's Happening?The green you see comes from chlorophyll, the chemical that makes the leaf green. The other colors are in the leaf but you can not see them because in the spring and summer, the plant produces so much chlorophyll. In the fall, the plant is getting ready to rest for winter. As the days become shorter and the weather turns colder, the plant stops making food. The other colors can then shine through the leaf.
Go to Science Made Simple to find more information about the color of Autumn Leaves.