Lesson 2: Autumn Leaves Fall

Fall Colors Experiment

Activity Developed by the University of Colorado Museum of Natural History

Description/Learning goals:

Participants will make connections to the natural patterns of the seasons.

Participants will practice making hypotheses- which colors will come out of the different leaves?


  • Clear glass jars or cups
  • Coffee filters or absorbent paper towels
  • Leaves of various colors
  • Rubbing alcohol (70% isopranol – readily available in grocery stores. It’s the same thing we use to sterilize cuts and scrapes)
  • Fork or grinding materials

Activity Instructions:

  1. Collect leaves from your neighborhood. If it’s not fall, you can still do the experiment with green leaves.
  2. Sort the leaves by color into separate jars, and tear up into small pieces, grinding them up as small as possible.
  3. Cover the leaves with rubbing alcohol, and continue to mix the leaves around in the liquid until the color moves into the alcohol.
  4. Place the edge of a coffee filter into each jar, allowing the liquid to travel up the rest of the dry filter.
  5. Observe as color begins to pull up into the filter. Leave in overnight to see how the colors will fully disperse.

Science Concepts:

How do leaves collect the sunlight? Inside each leaf there is a green pigment called chlorophyll. This molecule absorbs the sun’s light energy and turns it into chemical energy the plant (and all animals that eat the plant) can use. There are other colors within the leaf throughout the year, but these are hidden by the amount of green chlorophyll in the leaves.

Photosynthesis This is the process that plants use to make their food. They absorb sunlight, water and carbon dioxide (what we breathe out), and through a chemical process create glucose, a type of sugar, to feed itself. The plant also exhales oxygen through this process, providing what we need to breathe!

Changing of leaf color: As winter gets near, the days grow shorter. Trees stop producing food in their leaves and absorb energy into the trunk and roots where it will be kept safe for winter use. The green chlorophyll goes away, and the other yellow-oranges and pink-reds become visible in the leaf. Finally, the leaves fall off the tree.

Early Learning 101: Patterns: The recognition of patterns, sequencing, and critical thinking skills necessary to predict and classify objects in a pattern

While collecting leaves for this project, have your child sort the leaves by color, size, etc.

People and the Environment: The understanding of the relationship between people and the environment in which they live.

Go on a walk to collect the leaves for this project. Take your time and look around for animals and people. How are the animals behaving? Are they collecting food for the winter? Are people dressed differently than they would be in the summer?

Follow Up:

If you collect your leaves from a specific tree, try to return to that tree a few times through the remainder of the fall. Did the leaves change color in the way you thought they would? Were all the leaves the same color? Do you notice any animals living in or around the tree?

Book Suggestion: Little Yellow Leaf by Carin Berger