Find the Hidden Colors of Leaves

Introduction

Have you ever wondered why leaves change from green to an amazing array of yellow, orange, and red during the fall? Leaves get their brilliant colors from pigments made up of various color-creating molecules. During the warm, sunny months, plants use their leaves to turn sunlight into food energy, a process called photosynthesis. This primarily uses a pigment that reflects green light, which gives the leaves their characteristic color. In autumn, when colder, shorter days arrive, many kinds of trees no longer make food energy with their leaves and, consequently, no longer need the green pigment. The leaves' other pigments, some of which were already there during summer, become visible. In this science activity, you will uncover these hidden colors by separating plant pigments with a process called paper chromatography. What colors will you see?

Credits

Materials

• Leaves at different stages of turning fall colors (the more the better — about 10 of each color, from the same tree, is best)
• Scissors
• Strong, white, heavyweight, ultra-absorbent paper towels or chromatography filter paper that can be purchased separately from our partner Home Science Tools. Note: Chromatography paper works much better than paper towels. If you use paper towels, make sure to use thick paper towels as these result in better color separation.
• Ruler
• Pencil
• Clothespins or large paper clips (3–4 for each group of leaves)
• Toothpicks
• Strong, sturdy, and heat resistant drinking glasses (one for each group of leaves)
• Tall glass jars, such as mason jars (one for each group of leaves)
• Wooden spoon or another wooden utensil with a blunt end for crushing leaves
• Fork
• Plate
• Very small bowls or tea-light candle holders (one for each group of leaves)
• Isopropyl rubbing alcohol, 90%
• Measuring spoon, tablespoon
• Stove
• Tap water
• Pot