Animals, Plants & Seasons 3-minute video · ages 4-8 · free coloring page
Why do leaves change color in autumn?
Why do some trees turn red, some turn yellow, and some stay green all year long?
3 min
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Free coloring page
The scene from the video as a coloring page, plus the three-sentence answer, the experiment, and a QR code back to this page. One sheet, US Letter, black and white.
The answer in three parts
Why?
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In summer, every leaf is full of tiny green helpers.
They are called chlorophyll. They catch sunlight and make food for the tree. They are so green that they hide every other color.
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When autumn comes, the green fades and the yellow shows up.
The days get shorter and the nights get colder, so the tree stops making new green helpers. Under the green, yellow and orange paint was hiding all summer. It is called carotenoids. Ginkgo and birch trees do this.
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Red is a brand new paint.
It is called anthocyanin, and the leaf makes it in autumn! On sunny days, sugar gets stuck in the leaf and turns into red paint, like sunscreen for the leaf. Maple trees do this.
For grown-ups: The second mystery: why does a tree change color from the top, or from one side? Every leaf gets a different amount of sun, wind and cold. Leaves at the top and on the sunny side get the most sunshine, so they make lots of red paint, and they feel the cold night air first. Leaves deep inside are shaded and cozy, so they change later. A branch that has been hurt, or gets less water, can change early too. Autumn color is like a relay race.
Every tree has its own color recipe
- Greenchlorophyll
- Yellow and orangehidden carotenoids
- Redbrand new anthocyanin
- Always greenpine needles
A tiny experiment
Try it!
Color detective
You need: a tree that is changing color, and a grown-up
- Next time you go outside, find a big tree that is changing color.
- Look at the top, the sunny side, and the leaves hidden deep inside.
- Can you spot where the colors start?
What happened? The top and the sunny side get the most sun and feel the cold first, so they change first. The color then spreads through the whole tree.
Did you know?
Why do pine trees stay green? Their needle leaves have a waxy coat that fights the cold, and each needle lives for years. They drop only a few at a time, so the tree is always green.
The yellow and orange in leaves is the same stuff that makes carrots orange!
Your guide in this video
Hi friends! I'm Leafy. Today we will solve two big autumn mysteries about colorful trees!
Leafy is a little green leaf who knows every tree's color recipe.
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