Have you ever raked up a big pile of leaves in the fall and then jumped into them? It’s so much fun! But have you ever wondered why leaves change color in the fall? Let’s explore this colorful mystery together!
In the fall, you might notice that the leaves on trees turn beautiful shades of yellow, orange, and red. But why does this happen? Let’s find out!
Leaves start out green because they contain something called chlorophyll. Chlorophyll is a special substance that helps leaves make food for the tree using sunlight. This is why leaves look green during the spring and summer.
As fall arrives, the days get shorter, and there is less sunlight. Trees start to prepare for winter. They begin to save energy by pulling nutrients from the chlorophyll in the leaves back into their branches and trunks. This way, the tree can use these nutrients again when spring comes.
When the green chlorophyll is taken away, other colors that were hiding in the leaves start to show. These colors can be yellow, orange, brown, or even red! That’s why leaves change color in the fall.
Even though the leaves change color and fall off, it doesn’t mean the tree is sick or dying. It’s just getting ready for winter. When spring arrives, the tree will use the saved nutrients to grow new green leaves again.
Now that you know why leaves change color, you can try a fun activity that combines science and art. You can create your own colorful leaf art using different materials. Look for a step-by-step guide to this activity at the end of this article!
There are so many mysteries in the world around us. Keep asking questions and exploring! Who knows what amazing things you might discover next?
Thanks for joining us on this colorful journey. Stay curious, and see you next time!
Here’s a sanitized version of the transcript:
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One of my favorite things to do in the fall is to rake up a big pile of leaves and then run and jump into them. Someone named Nikhil has a question about leaves. Let’s give him a call.
Hi, Nikhil! I have a question for you: Why do leaves change color in the fall? That’s a great question! You’ve probably noticed leaves changing color in the fall, and they can be so pretty with all those different colors—yellow, orange, red. But why do they do this?
Leaves start out green, and then in the fall, they turn different colors. What do you think? Why do you think leaves change color in the fall? Now would be a good time to pause the video and discuss.
Okay, you ready? I don’t know what ideas you might have come up with, but think about this: If you’ve ever forgotten to water a plant, you might have seen its leaves turn kind of yellow or brown. The plant is dying. Could it be that trees’ leaves are changing color because the trees are dying?
Well, it might look like the trees are dying. In fact, by the end of fall, the leaves actually fall off the tree. We think that might even be why we call the season “fall.” But think about it: a few months later, after winter has passed, springtime comes around, right? In spring, trees grow back new leaves, and they look healthy again. So when a tree’s leaves change color, that probably doesn’t mean it’s dying or sick.
So why would leaves change color in the fall? Now, I have to tell you, this is a question that is not easy to answer. It took scientists hundreds of years to figure it out. It was a real puzzle. First, using microscopes and other tools, scientists discovered that leaves contain a green substance called chlorophyll. This is actually why leaves look green; it’s because they’re filled with chlorophyll.
But now here was the really hard part to figure out: Why do leaves stop looking green in the fall? One clue scientists discovered is that in the springtime, when a tree is growing new leaves, it has to do a lot of hard work to make chlorophyll. Chlorophyll contains special nutrients that the tree pulls from the soil around it. That’s when scientists realized that every fall, if a tree were to drop its leaves while they’re still green, it would lose all the special nutrients that it used to make the chlorophyll.
So instead of losing the leaves when they’re green, trees have a way of saving some of those special nutrients. Here’s what they do: before its leaves fall off, a tree pulls some of the nutrients from the green chlorophyll into its branches and trunks, places where the nutrients can be stored safely during the cold winter.
So you see, that’s why the leaves stop looking green in the fall. The green chlorophyll is getting taken apart and moved out of the leaves. Now, that might make you think that in the fall, the leaves should look colorless once there’s no chlorophyll left in them. But it turns out chlorophyll isn’t the only colored substance in the leaves. Leaves also have substances inside them that can be yellow, orange, brown, or even red in special cases.
So when trees pull some of the chlorophyll nutrients into their trunks and branches each fall, we begin to see some of the other colored substances in the leaves—browns, yellows, oranges, or reds—that are left behind. That’s why leaves change color in the fall.
In summary, when leaves change color in the fall, it doesn’t mean trees are dying or sick. It took scientists a long time to figure it out, but they discovered that in fall, trees are pulling nutrients from the green chlorophyll in their leaves to store them for winter. Then in the springtime, trees reuse those nutrients to grow a new set of green leaves.
That’s all for this week’s question. Thanks, Nikhil, for asking it! Now we have something special for this episode. My friends and I here at Mystery Science have created a step-by-step activity that combines science with art. You can find a link to the activity at the end of this video.
For the next episode, I reached into my question jar and found three questions submitted to me that I’m thinking about answering. When this video is done playing, you’ll get to vote on one. You can choose from: How are staples made? Were dragons ever real? Or why do light bulbs get hot? So submit your vote when the video is over. I want to hear from all of you watching. There are mysteries all around us. Stay curious, and see you next week!
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This version removes informal language, typos, and any unclear phrasing while maintaining the original meaning and flow of the content.
