Photograph by Davidgn / Dreamstime
Photograph by Davidgn / Dreamstime

Need some re-leaf? Try these tree-tastic science experiments to keep kids busy this fall.

Bonus: They double as art projects!

“Why do leaves change color?”

It’s a question parents might dread more than “Why is the sky blue?” But the answer will not only make you look like a genius, it’ll inspire curiosity, outdoor exploration, and scientific discovery in your child. And when combined with fun leaf activities, kids can develop their creative muscles as well.

Revealing the secret life of leaves to kids

Plants produce green, yellow, red, and orange pigments in their leaves. The green pigment is called chlorophyll. In the spring and summer, plants produce a lot of it to capture energy from the sun to produce food. (You remember photosynthesis from eighth grade, right?) Other pigments also help with photosynthesis, but there’s so much chlorophyll that you can’t see those colors.

In the fall, reduced light and cooler temperatures decrease the flow of nutrients and water between the tree and leaves. Chlorophyll production declines, and the green pigment breaks down. That’s why you can now see the other colors. Since the leaves aren’t producing as much food, the tree doesn’t need them. So a special layer of cells at the base of the leaf stalk disappears, and the leaves fall to the ground.

Now that you’ve impressed your kids with your newfound tree knowledge, impress them even more by showing them some fun with leaves. These artsy activities will help foster observation and creativity—and will be way more fun than raking.

Extracting Fall Colors

In this activity, kids get to play with the plant pigments! Have your kids gather green, yellow, and red leaves. Aim for about 5 to 10 of each shade. They can be from one kind of tree or a variety. (Safety tip: Have kids wear eye gear like sunglasses to protect from splashes. Also, be warned: Plant pigments may stain clothes.)

You’ll also need:
• An assortment of small ceramic bowls or containers
• Scissors
• Spoons
• Isopropyl (rubbing) alcohol
• 5-x-½-inch-long paper strips for each color of leaf; watercolor paper, coffee filters, and thick paper towels work best.

What do to:
• Sort leaves into piles by color.
• From each pile, select and cut up three to five leaves into tiny pieces; the smaller the better.
• Put each pile into a bowl, then add about one to two tablespoons of isopropyl alcohol.
• Crush the leaf mixture with a spoon for up to five minutes. Repeat with other leaves in separate containers.
• Place one end of the paper into each container so that it touches the leaf mixture.
• Watch what happens! After 30 to 60 minutes, remove the paper and allow to dry on a paper towel or newspaper.

What’s happening: Crushing the leaves breaks down the cells and releases the molecule-size pigments. The alcohol helps extract the pigment from the leaves so that the paper can absorb the mixture.

Now that your kid has mastered the basics, here are some other fun, leafy activities.

Compare Colors. Mix up the extraction activity from above. What happens if all the leaf colors are used together? What color or colors travel up the paper? Other options: Collect leaves from different kinds of trees, then use one color and type of leaf per container (for example, red maple leaves versus red dogwood leaves). Compare and contrast the results to find out if one kind produces darker or brighter colors.

Fall Art Paper. Carefully pour the crushed leaf mixture onto one side of a piece of paper, then fold the paper in half to cover the leaves. Use a rolling pin or large spoon to press the paper together to extract the color. Let it sit for two to three minutes. Unfold and scrape off the crushed leaves. (You can reuse this mixture for the Sprinkle Leaf Art craft below.) Allow the paper to dry flat. Use the paper as stationery, to make other crafts, or as a piece of fall art to decorate your room.

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Sprinkle Leaf Art. Have your child draw a tree trunk and branches with crayons on any kind of paper. Spread liquid glue over branches and on the ground around the trunk. Use a spoon to sprinkle the crushed leaves over the branches and ground (like glitter). Allow to dry. Shake off and dispose of the excess leaves. Display after allowing the craft to dry.

Pressed Leaves. Create bookmarks, art, or stationery with dried leaves. Select ones from the ground that still have a bit of moisture in them—they’ll be brighter and flexible. (Dry leaves that have been on the ground for a while will be brittle and break.) Use these instructions for flower pressing for your leaves.

Leaf Prints: Hold a leaf by its stem and brush one side with finger- or tempera paint in a fall hue. Gently press the painted side of the leaf onto paper (any kind). Lift the leaf by the stem to it like a stamp until the paint needs replenishing. Repeat the process with other paint colors and different shapes of leaves.

Track a Tree. Take a photo of the same tree from the same position every day for a week or two as it changes colors. Kids can observe color changes as well as how the loses its leaves. Create a time-lapse movie using a moviemaking app to watch how the tree changes from beginning to end.