Overview
Green leaves look green because chlorophyll dominates — but they contain other pigments too. This project uses paper chromatography to separate those pigments. You'll crush leaves into rubbing alcohol, then let the liquid wick up a coffee filter strip, carrying the pigments with it at different speeds. The result is a series of color bands that reveal what's hiding inside every leaf.
What You'll Learn
- What chromatography is and how it separates mixtures
- Why leaves appear green and what other pigments they contain
- How to identify chlorophyll, xanthophyll, and carotenoids
- How to record and interpret a chromatography strip
Background
Chromatography works because different molecules travel at different speeds through a material. Pigments that interact more strongly with coffee filter paper move more slowly. Green chlorophyll moves at a moderate rate, while yellow xanthophylls and orange carotenoids spread to different positions. In autumn, when trees stop making chlorophyll, these hidden colors are finally revealed — which is why fall foliage is yellow and orange.
Safety note: Rubbing alcohol is flammable. Keep away from open flame. Adult supervision for younger children.
Materials
Everything on this list is either free or available at a dollar store. No lab equipment required.
Step-by-Step Procedure
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1
Collect leaves
Gather 4–6 different leaves. Include one spinach leaf and at least one outdoor leaf for comparison.
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2
Extract pigment
Tear leaves into small pieces and pack them tightly into jars. Cover with rubbing alcohol and crush/stir to release pigments. The alcohol should turn green.
💡Use a spoon to crush the leaves firmly
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3
Cut filter strips
Cut coffee filters into strips about 1 inch wide and 5 inches long.
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4
Set up chromatography
Dip just the very tip (half an inch) of each strip into the green alcohol. Rest the strip against the jar so the tip stays submerged but the strip does not fall in.
💡Do not let the strip fall fully into the liquid
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5
Wait
Leave undisturbed for 30–60 minutes as the alcohol wicks up the strip.
💡The slower you go, the better the separation
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6
Remove and dry
Take out the strips and let them dry flat.
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7
Record results
Label where each color band appears on each strip. Compare strips from different leaf types.
Expected Results
You will see at least 2–3 distinct color bands on most leaves: green (chlorophyll), yellow or yellow-green (xanthophyll), and sometimes orange (carotenoids). Spinach typically shows the most distinct separation. Outdoor leaves often surprise with colors you did not expect.
Your results may differ — and that's valuable data, not a mistake. Document what you actually observed, not what you expected.
Going Further
Compare deciduous vs evergreen
Do pine needles contain the same pigments as maple leaves?
Test autumn leaves
Run the same experiment with a red or orange fall leaf and see how the pigment profile changes.
