Every autumn children ask the same great question: why do the leaves change color? The answer is a short science lesson about light, food and pigments. You can show it with a simple experiment, then read a fall story about leaves. More fall books and activities are on our fall page.
The simple answer
- Summer: leaves are full of chlorophyll, a green pigment that captures sunlight so the tree can make food (sugar). This is called photosynthesis.
- Fall: days get shorter and cooler. The tree gets ready for winter and stops making chlorophyll.
- Colors appear: as the green fades, yellow and orange pigments called carotenoids (the same family that colors carrots) become visible. They were in the leaf all summer, hidden by the green.
- Reds and purples: some trees, such as many maples, make new pigments called anthocyanins in fall, which give red and purple leaves.
- Brown: when all the pigments break down, leaves turn brown and fall.
Try it: the leaf chromatography experiment
With an adult’s help: tear a few green leaves into tiny pieces, put them in a small jar and cover them with a little rubbing alcohol. Stand a strip of coffee filter in the jar with one end in the liquid and leave it for an hour or two. As the liquid creeps up the paper, bands of color separate. Often you will see yellow hiding behind the green. Record what you see on a science observation journal.
Safety: rubbing alcohol is flammable and should only be handled by an adult, away from heat.
Grab the free reading log 📚
A clean, print-ready log to track books, minutes, and little wins — plus the occasional reading tip. No spam, unsubscribe anytime.
Fall leaf picture books
Read these free leaf stories after the experiment: Leaves, Ten Falling Leaves, Maya’s Leaf Collection and The Little Leaf. Ask your child to point out the leaf colors on each page and say which pigment makes them.
Fall science worksheets
- Fall science experiment (grade 1)
- Fall science sequencing (grade 1)
- Fall science vocabulary (grade 1)
- Fall science experiment (grade 2)
- KWL chart: what I know, want to know, learned
Learn more from trusted sources
For more detail, see the U.S. Forest Service, which publishes fall color information each autumn, and NASA Space Place: What causes the seasons? to explain why fall days get shorter.
Read free fall leaf stories and print a fall science worksheet.