Why Leaves Change Color

1. What is the name of the green chemical that helps leaves make food from sunlight?

• A. Anthocyanin
• B. Chlorophyll
• C. Tannin
• D. Carotenoid

2. What do plants need to create their sugary fuel during photosynthesis?

• A. Soil, rocks, and sand
• B. Water, carbon dioxide, and sunlight
• C. Sugar, heat, and oxygen
• D. Rain, wind, and soil

3. Why do leaves appear green during the summer?

• A. Because there is so much chlorophyll it hides other colors
• B. Because the sun paints them green
• C. Because the leaves are eating chlorophyll
• D. Because they are reflecting only red light

4. What causes trees to start changing colors for autumn?

• A. The first frost of the year
• B. The tree getting sick
• C. The shorter days and longer nights
• D. The tree needing to drink more water

5. What colors are caused by the hidden carotenoids in leaves?

• A. Red and purple
• B. Brown and black
• C. Yellow and orange
• D. Blue and green

6. What are anthocyanins responsible for in autumn leaves?

• A. Making the leaves turn bright red
• B. Making the leaves turn brown
• C. Helping the leaf absorb water
• D. Keeping the leaf green all winter

7. What is the 'abscission layer' in a tree?

• A. A protective wax layer
• B. A type of chemical that makes leaves drop
• C. The 'scissor' cells that cut off the leaf's water supply
• D. The part of the leaf that holds sugar

8. Why do trees enter a state called 'dormancy'?

• A. To grow bigger flowers
• B. To rest and save energy during winter
• C. To hide from animals
• D. To change their colors faster

1. If a tree has very bright red leaves in autumn, what does this tell you?

• A. The tree is sick and dying
• B. The tree had a very successful, healthy summer
• C. The tree did not get enough sunlight
• D. The tree is missing its green blanket

2. Why do oak leaves stay brown and crunchy on the ground for a long time?

• A. They contain tannins which do not break down quickly
• B. They are full of chlorophyll
• C. They are still connected to the tree
• D. They have a waxy coating like a pine tree

3. How do evergreens stay green throughout the winter?

• A. They don't have chlorophyll
• B. They produce more red pigment to stay warm
• C. They have a waxy coating and needle-shaped leaves to protect them
• D. They keep moving water from the roots all winter

4. Why would a tree stop making chlorophyll in the fall?

• A. It wants to change colors for decoration
• B. It is trying to save energy because it cannot use the chlorophyll in winter
• C. It is running out of green dye
• D. It wants the leaves to fall off as fast as possible

5. Why do scientists say the length of the day is the tree's 'clock'?

• A. Because trees have tiny internal gears
• B. Because it is the most reliable way for a tree to track the changing seasons
• C. Because it is the only way for the tree to measure temperature
• D. Because the sun moves at different speeds

6. What is the main reason trees drop their leaves before a big snowstorm?

• A. To keep the ground fertilized
• B. To allow sunlight to hit the ground
• C. To prevent snow from piling up and snapping the branches
• D. To get rid of old, broken leaves

7. If you see the top leaves of a tree changing color before the ones at the bottom, why is this?

• A. The top leaves are older
• B. The top leaves get the most sunlight and are ready to sleep first
• C. The bottom leaves are hiding from the cold
• D. The bottom leaves are producing more sugar

8. Which of these is a valid scientific reason for plants having pigments?

• A. To make the forest look pretty for humans
• B. To attract bees and protect the plant from the sun
• C. To help the tree walk to find water
• D. To make the leaves heavy so they fall faster