Why Do Maple Leaves Turn Red? Lesson Plan

A Fall-Themed Elementary Kinesthetic Science Activity (and Craft!)

© Renee Carver

Aug 29, 2008

As leaves on maple trees flame bright red this fall, use a controlled experiment to teach science content and produce patterned leaves that can be used to create decorative banners. (This experiment can be performed on any tree with leaves that turn red or purple, such as a sweet gum, red oak, or dogwood.)

Objectives

1. Students will demonstrate an understanding of the process by which maple leaves change color by performing a controlled experiment to prove that maple leaves need sunlight to turn red.
2. Students will use the leaves from the experiment to craft maple-leaf banners.

Materials

• Red Leaf, Yellow Leaf by Lois Ehlert [Harcourt, 1991]
• A Tree for All Seasons by Robin Bernard [National Geographic, 2001]
• Why Do Leaves Change Color? by Becky Maestro [HarperCollinsPublishers, 1994]
• Science logs
• Maple trees (in fall)
• Rolls of 2-inch masking tape
• Scissors
• Roll of butcher paper
• Glue
• Colored markers

How Do Maple Leaves Change in the Fall?

1. Build background by reading aloud the books Red Leaf, Yellow Leaf and A Tree for All Seasons and discussing children's prior observations of maple trees in the fall.
2. Have children describe in their science logs how a maple leaf changes during fall. (It turns from green to yellow, orange, and especially red.)

Why Do Maple Leaves Turn Red?

1. If possible, perform the activity "Why do autumn leaves change color?"
2. Otherwise, read Why Do Leaves Change Color? and discuss what it says about why leaves are green and why some leaves turn red.
3. Have children summarize in their logs why green leaves turn red. (A green pigment called chlorophyll colors leaves and blocks other pigments. When leaves die and old chlorophyll is no longer replaced, yellow and orange pigments become visible. Sunlight turns sugar stored in some leaves to red pigment.)

Discuss the Experiment

1. Have children record in their logs the hypothesis, or suggested explanation for why something happens, that exposure to sunlight is what causes a maple leaf to turn red.
2. Ask children to record the following procedure: A.) Cover parts of green maple leaves with tape. B.) Observe covered and uncovered leaves over time. C.) Remove tape and compare the colors of covered parts and uncovered parts.
3. Have children write a prediction about what colors the covered and uncovered parts will turn.

Perform the Experiment

1. Ask children to cut out masking-tape shapes or letters that spell messages and stick each piece to the surface of a green leaf growing on a maple tree, placing pieces on the sides of the leaves that are most exposed to the sun.
2. Explain that the leaves with tape are the experimental group, or the group that is testing the hypothesis, while the leaves without tape are the control group, or the group that is left alone to be used for comparison.
3. Have children describe in their logs what both groups of leaves look like at this time.
4. Return several times over the course of the next few weeks. Have children record their observations of both groups each time.
5. Once the control group has turned red, have children pick the experimental group leaves, carefully peel off the tape pieces, and record their observations one last time, checking the final results against their initial predictions.

Assessment

Ask children to summarize in their logs the results of their experiments and explain why they think the experiments turned out the way they did. Children should have found that the leaf surfaces covered by tape have turned yellow or orange, while all the leaf surfaces that were exposed to sun in both the control group and the experimental group have turned red, thus showing that exposure to sunlight is needed to turn maple leaves red.

Enrichment Craft Activity

Provide children with colored markers, glue, and lengths of butcher paper. Have them glue their patterned leaves to the butcher paper and decorate the paper with markers to create fun, fall-themed banners.

For further enrichment, try other primary-level, fall-themed activities in the curriculum areas of art and science.

Red Maple Leaf

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