Why Do Leaves Change?

Melinda Cortez

Tier 1

Lesson Plan

Why Do Leaves Change? Lesson Plan

Students will be able to identify the key reasons why leaves change color in the fall, including the role of chlorophyll and other pigments.

Understanding why leaves change color helps students appreciate natural phenomena, introduces basic biology concepts, and fosters curiosity about the world around them.

Audience

3rd Grade

Time

30 minutes

Approach

Through an engaging reading passage, interactive slides, and a creative activity.

Materials

Why Do Leaves Change? Slide Deck, and Why Do Leaves Change? Information Passage

Prep

Review Materials

10 minutes

Review the Why Do Leaves Change? Slide Deck to familiarize yourself with the content and talking points.
Read through the Why Do Leaves Change? Information Passage to understand the concepts and features.
Gather any additional materials if you plan to extend the lesson (e.g., real leaves in various colors).

Step 1

Introduction: Hook the Students

5 minutes

Begin by asking students what they notice about trees in the fall. (2 minutes)
Introduce the question: "Why do leaves change color?" Use Why Do Leaves Change? Slide Deck Slide 1-2. (3 minutes)

Step 2

Read and Explore

15 minutes

Distribute the Why Do Leaves Change? Information Passage.
Explain that they will read to find out the scientific reasons behind the color change.
Guide students to read the passage, paying attention to the print and graphic features. Encourage them to highlight or underline key information. (10 minutes)
Facilitate a brief discussion about what they learned from the passage. Use Why Do Leaves Change? Slide Deck Slide 3-5 to reinforce concepts like chlorophyll, photosynthesis, and other pigments. (5 minutes)

Step 3

Creative Connection (Activity)

10 minutes

Have students draw a tree and color its leaves in fall colors. Ask them to label at least two parts of the tree or leaf based on what they learned (e.g., "chlorophyll fades," "red pigment shows"). This can be a quick sketch on a blank paper or in their science notebooks.
Ask a few students to share their drawings and what they labeled. Use Why Do Leaves Change? Slide Deck Slide 6-7 to conclude and review key takeaways.

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Slide Deck

Welcome, Fall Explorers!

What do you notice about trees in the autumn?

Greet students and start with a warm question to gauge their observations about fall. What colors do they see?

The Big Question:

Why do leaves change their colors when autumn arrives?

Introduce the main question of the lesson. Engage students with their own ideas before revealing the science.

Green Power!

Chlorophyll is the green stuff in leaves that helps plants make food from sunlight.
It's like the plant's chef!

Explain chlorophyll simply. Ask students if they remember what plants need to grow (sun, water, etc.).

Fading Green, New Colors!

As days get shorter and colder, the plant stops making chlorophyll.
The green color starts to fade away.

Connect chlorophyll to the fading green color. What happens when the chef goes on vacation?

Hidden Colors Appear!

Other colors, like yellow, orange, and red, are hiding in the leaves all summer.
When green fades, these beautiful colors can finally shine!

Introduce other pigments. You can mention that these colors were always there, just hidden!

The Science of Fall Colors

Leaves change color because:

Chlorophyll (the green) fades.
Yellow and orange colors, always there, become visible.
Red and purple colors are made in the fall.

Recap the main ideas. Have students do a quick turn-and-talk about one new thing they learned.

Nature's Beautiful Secret

Now you know the amazing science behind why leaves put on their spectacular fall show!

Conclude the lesson. Encourage students to look for these colors and think about the science next time they see fall leaves.

Reading

Why Do Leaves Change Color in the Fall?

As summer days grow shorter and the air gets crisp, a magical change begins. The green leaves on trees, which have been so busy all summer, start to transform into brilliant reds, oranges, and yellows. Have you ever wondered why?

The Green Machine: Chlorophyll

During spring and summer, leaves are like tiny food factories for the tree. They are packed with a green chemical called chlorophyll (say: KLOR-uh-fill). Chlorophyll helps the leaves capture sunlight to make food for the tree in a process called photosynthesis (say: FOH-toh-SIN-thuh-sis).

Green leaves on a tree in summer
Caption: Bright green leaves soak up the sun in summer, thanks to chlorophyll.

Chlorophyll is so strong that it covers up all the other colors that are also in the leaf. Think of it like wearing a big green blanket that hides your colorful clothes underneath!

The Disappearing Act

As autumn arrives, the weather changes. Days become shorter, and nights get colder. The trees get a signal that it’s time to rest for the winter. They stop making chlorophyll. Slowly, the strong green color starts to fade away.

Key Term: Photosynthesis

This is the way plants use sunlight to make their food. It happens mostly in the green parts of the plant.

Hello, Hidden Colors!

Once the green chlorophyll breaks down and fades, the other colors that were always there in the leaves can finally be seen!

Yellows and Oranges come from chemicals called carotenoids (say: kuh-ROT-uh-noyds). These are the same chemicals that make carrots orange and corn yellow. They have been in the leaves all along, just hidden by the chlorophyll.
Reds and Purples are a bit different. These beautiful colors are made in the leaves during the fall, especially when there are warm, sunny days and cool, crisp nights. These colors come from chemicals called anthocyanins (say: AN-thoh-SY-uh-nins). They help protect the leaves as they get ready to fall off the tree.

A vibrant array of red, orange, and yellow fall leaves
Caption: After chlorophyll fades, other pigments reveal stunning fall colors.

So, the next time you see a tree bursting with fall colors, remember the amazing science happening right before your eyes! It’s all thanks to the clever chemicals in the leaves.