You know fall has arrived when leaves change from green to bright shades of yellow, orange, red, and brown. But why do leaves change color in the fall?
The answer involves sunlight, chlorophyll, and the different pigments hidden inside leaves. Explore the science of fall leaves, then use our printable Why Do Leaves Change Color lapbook project for a hands-on way to extend the learning.
Field: Life Science / Plant Science
Grades: 1–5
Concepts: leaves, chlorophyll, pigments, photosynthesis, seasonal change
Why Do Leaves Change Color?
Leaves look green during spring and summer because they contain chlorophyll, a green pigment that helps plants absorb light energy from the sun.
Plants use this light energy during photosynthesis to make the food they need to grow.
As fall approaches, the days become shorter, and there is less sunlight. Trees begin preparing for winter, and chlorophyll production slows down.
As the chlorophyll breaks down, the green color fades and other pigments in the leaves become easier to see.
👉 Learn more about how photosynthesis works.
Why Are Leaves Green?
Chlorophyll absorbs sunlight that plants use during photosynthesis.
Because chlorophyll reflects more green light than other colors, most healthy leaves appear green during the growing season.
Even though we mostly see green, leaves can contain several different pigments at the same time.
👉 Try this chlorophyll experiment with green leaves or with spinach!
What Happens to Chlorophyll in Fall?
Shorter days are one of the main signals that tell trees the growing season is ending.
As daylight decreases, trees produce less chlorophyll. The chlorophyll already in the leaves begins to break down. Once the green fades, other colors become visible.
Why Are Fall Leaves Different Colors?
Different pigments create the colors we see in fall leaves.
- Yellow and orange: These colors come mainly from pigments called carotenoids. They are often present in leaves throughout the growing season but are hidden by chlorophyll.
- Red and purple: These colors can come from anthocyanins, which some trees produce during the fall.
- Brown: Brown colors often come from tannins and from leaf tissue drying and breaking down.
💡 Different types of trees contain different pigments, which is one reason fall leaves can vary so much in color.
5 Fun Facts About Fall Leaves
- Leaves can contain several pigments even when they look completely green.
- Shorter days help trigger the changes that happen in leaves during fall.
- Yellow and orange pigments may already be present before the green color disappears.
- Some trees produce red and purple pigments during autumn.
- Different tree species can produce very different fall colors.
Try a Leaf Chromatography Experiment
Want to look for some of the pigments hidden inside leaves?
👉 Try our Leaf Chromatography Science Experiment to separate leaf pigments and explore the science behind fall color changes. It makes a great companion activity to this lesson.
Free Why Do Leaves Change Color Lapbook
Our printable fall leaves lapbook gives kids a hands-on way to organize what they learn about leaves and seasonal changes.
💡 Use it as a stand-alone fall science activity or add it to a larger leaf unit.
Supplies
- File folder
- Why Do Leaves Change Color printable
- Colored crayons, markers, or pencils
- Scissors
- Glue or double-sided tape
How to Make Your Fall Leaves Lapbook
Step 1. Fold each side of an open file folder toward the middle to create the lapbook. Color the cover pieces and glue them to the front of the folder.
Step 2. Cut out the Why Do Leaves Change Color? banner and glue it near the top of the inside of the lapbook. Add the explanation section underneath.
Step 3. Cut out the six mini booklets. Fold and assemble each booklet using the dotted lines as guides, then glue them inside the lapbook.
Step 4. Glue the What I Learned About Leaves page to the back of the lapbook. Read through the finished project together and have kids write a few sentences about what they discovered.
👉 CLICK HERE TO GET YOUR PRINTABLE FALL LEAVES PROJECT
Prefer a Regular Printable Instead?
Not every classroom has time to cut and assemble a lapbook.
The Fall STEM Projects Pack also includes a non-lapbook Why Do Leaves Change Color activity, making it easy to explore the same science with a more traditional printable format.
You’ll also find additional leaf science activities, parts of a leaf resources, scavenger hunts, fall investigations, engineering challenges, and more.
👉 GET THE FALL STEM PROJECTS PACK
Guiding Questions
Use these questions for discussion, science journals, or small-group work.
- Why do leaves look green during spring and summer?
- What happens to chlorophyll as the days become shorter?
- Which leaf colors may already be present before fall?
- Why don’t all trees turn the same color?
- What pigments can you discover in a leaf?
- How could you investigate the colors hidden inside leaves?
More Leaf Activities to Try
Continue your fall leaf study with more hands-on science and art.
- Leaf Chromatography — Separate pigments hidden inside leaves.
- Parts of a Leaf — Explore basic leaf structure and function.
- How Do Leaves Drink Water? — Investigate how water moves through plants.
- How Do Plants Breathe? — Explore how plants exchange gases.
- Leaf Rubbings — Observe leaf shapes, veins, and textures with a simple art activity.
- Fall Leaf Art Projects — Combine science observations with creative fall art.
