Fall leaf chromatography: a two-part pigment lab for grades 6–8
What it is: a leaf chromatography lab where middle school students separate the pigments in green leaves using rubbing alcohol and coffee filter strips. Hidden yellow and orange bands show up, which explains why leaves change color each fall.
Time: two parts, about 20 minutes to set up and about 30 minutes to read results, an hour or more apart. Overnight works too.
Materials per team: a small glass jar, a handful of green leaves (spinach works if trees are already bare), isopropyl rubbing alcohol (70% or 91%), a metal spoon, plastic wrap or a lid, a white coffee filter cut into a strip about 2 cm wide, tape, a pencil, and safety goggles. Safety: rubbing alcohol is flammable and irritates eyes. Keep it away from heat and flames, open windows or run a fan, wear goggles, and have an adult pour it.
- Part one: students tear the leaves into tiny pieces, put them in the jar and mash them with the spoon for a minute.
- The teacher adds just enough alcohol to cover the leaf bits. Students mash again, cover the jar and predict: is green the only color inside? The alcohol slowly turns green as pigments dissolve.
- Part two: tape one end of the filter strip to a pencil and rest the pencil across the jar so the bottom of the strip just touches the liquid. The leaf bits should not touch the paper.
- Wait 30 to 60 minutes. The alcohol climbs the paper and carries pigments different distances. Students sketch and label the bands as they appear.
- Explain the science: leaves hold several pigments. Chlorophyll is green and is usually so plentiful that it hides yellow and orange pigments called carotenoids. In fall, many trees stop making chlorophyll as days shorten and nights cool, and the chlorophyll breaks down. The yellow and orange were there all along. Reds and purples come from different pigments some trees make in fall, called anthocyanins.
Differentiation: for students who need support, give a labeled sketch of what bands might look like and a word bank. For advanced students, measure how far each band traveled compared with the alcohol front and discuss why pigments separate (they dissolve and stick to paper differently). For English learners, post pigment, chlorophyll, carotenoid, dissolve and separate with color swatches. For students with sensory needs, offer gloves and a seat near the window, and let them take the sketching and timing role.
Quick check: in two sentences, explain why a leaf can turn yellow in fall without making any new yellow pigment.
If you try it, tell us which tree species gave your class the most bands.
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About this resource
- Shared by
- @UpOnlyLearning · Curriculum team
- Posted
- Oct 28, 2026
- Type
- Lesson plan
- Grade
- Grades 6–8
- Subject
- Science
- Language
- English
- License
- Free for classroom, co-op and tutoring use. Please don't resell.