Why Leaves Change Color
Understand chlorophyll and why leaves turn red and yellow in autumn
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The Basics of Changing Leaves
1. What is the main green pigment in a leaf called?
- A. Carotenoids
- B. Chlorophyll
- C. Humus
- D. Anthocyanin
2. What do plants use to make their food?
- A. Sugar and salt
- B. Sunlight, water, and carbon dioxide
- C. Dirt and rocks
- D. Oxygen and heat
3. Which pigments are responsible for the yellow and orange colors?
- A. Carotenoids
- B. Chlorophyll
- C. Anthocyanins
- D. Brown waste
4. What is the main signal that tells a tree it is time to prepare for winter?
- A. The smell of rain
- B. The shorter days of sunlight
- C. The number of birds nearby
- D. The color of the soil
5. Where are the red pigments (anthocyanins) created?
- A. They are hidden all summer
- B. They are brought in by the soil
- C. They are created fresh in the autumn
- D. They come from the rain
6. What happens to the leaf when it turns brown?
- A. It is making new food
- B. It is turning into chlorophyll
- C. It is dying and becoming waste
- D. It is getting ready to turn green again
7. What is humus?
- A. A type of insect
- B. A green leaf pigment
- C. Rich soil made from decomposing leaves
- D. A winter evergreen tree
8. Why do evergreen trees keep their leaves all winter?
- A. They have a protective waxy coating
- B. They don't need food
- C. They grow faster in the cold
- D. They don't have sunlight
Deep Thinking About Autumn Leaves
1. Why does a tree stop making chlorophyll in the autumn?
- A. To change its color
- B. To save energy for winter survival
- C. Because the tree is getting sick
- D. Because the leaves are too heavy
2. How are carotenoids like a box of crayons?
- A. They are used to draw on trees
- B. They are hidden beneath the green marker of chlorophyll
- C. They are made of wax
- D. They only appear when it rains
3. Why might red leaves be a 'sunscreen' for the tree?
- A. They help the tree grow in the dark
- B. They protect fragile leaves from sun damage
- C. They attract more rain to the leaves
- D. They make the leaves taste bad
4. What is the purpose of the 'cork' layer at the leaf stem?
- A. To help the leaf grow larger
- B. To trap sugar inside the leaf
- C. To block water from the ground
- D. To make the leaf change green
5. Why might a bright leaf color act as a signal to insects?
- A. It tells them the tree is a good place to live
- B. It tells them the tree is closing up shop
- C. It makes the leaves grow faster
- D. It tells them to eat the leaf
6. What is the relationship between a fallen leaf and next spring’s tree?
- A. The leaf provides nutrients to the soil for the tree
- B. The leaf turns into a new branch
- C. The leaf hides the roots from the cold
- D. The leaf makes sugar for the soil
7. Why is the idea that 'frost causes leaves to change' a misconception?
- A. Frost actually makes leaves turn purple
- B. Frost is not necessary; light changes are what matter
- C. Frost only affects evergreen trees
- D. Frost is too cold for trees to handle
8. How is a tree's leaf-drop similar to a person's winter preparation?
- A. It is a way of packing away summer routines to stay safe
- B. It is a sign that the tree is dying
- C. It happens because of the lack of sweaters
- D. It is just a random accident of nature
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