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Why do leaves change color in the fall?
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โ Why do leaves change color in the fall?๐ The short answerLeaves change color when chlorophyll (which we perceive as green) is replaced by other pigments, such as carotenoid and anthocyanin. ๐ The long answerItโs hard to imagine autumn without colorful trees and crunchy piles of leaves. But why do leaves change color? To answer that question, letโs start by understanding why spring leaves are green. The substance that makes leaves green is chlorophyll, a pigment that helps trees absorb sunlight and convert it into energy. This process is known as photosynthesis.
At the beginning of fall, the temperature drops and the nights get longer. This signals to trees that itโs almost winter and resources are becoming scarce. To conserve energy, trees stop producing chlorophyll, and the chlorophyll in their leaves begins to break down. When the chlorophyll is depleted, other pigments in the leaves take center stage. Carotenoid pigments appear as yellow or orange, while anthocyanin pigments appear as red or purple. Without chlorophyll to mask them, these pigments cause the leaves to appear yellow, orange, or red. Left: Close-up view of yellow carotenoid pigments from a persimmon rind. Right: Close-up view of purple anthocyanin pigments in an unidentified flower cell. Left: "ะะพะถััะฐ ั ััะผั" by Andrei Savitsky is licensed under CC BY 4.0. Right: "Microscopic view of unidentified flower cells with anthocyanins (4x magnification)" by Shkyrik is licensed under CC BY-SA 4.0. So why do leaves fall to the ground after they change color? Since chlorophyll produces the energy leaves need to stay alive, leaves slowly weaken without it. Throughout the fall season, they gradually separate from the tree until they fall to the ground. While this process might seem sad, itโs a completely natural part of a leafโs life. Itโs actually a positive thing for nature as a whole! Rather than using up a treeโs much-needed energy, fallen leaves are able to serve as food for animals or fertilizer for the soil. Losing leaves also helps the tree survive through the chilly winter so it can sprout new leaves the next year. ๐ฉ Subscribe to Madeline's newsletterIf you enjoyed today's post, I recommend you join Bluestocking, for more easy-to-understand breakdowns of science, history, and geography.
๐ Book of the weekโThe Elements of Styleโ by William Strunk Jr.โ & โE.B. WhiteโI've been trying to read more books on how to write better (for you, dear reader). This one is a must! I loved how this guide is concise and straight-to-the-point. There are plenty of examples to showcase okay writing vs. great writing, and I found myself noting down some key takeaways: "Omit needless words" will stay with me for life. โ ๐ Catch up on other curious questions
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๐ก Today You Should Know
Learn something new every Friday. Join 2,000+ nerds and satisfy your curiosity one question at a time with topics including science, technology, history, and more.
Why donโt woodpeckers get brain damage? ๐ The short answer Woodpeckers avoid brain damage thanks to special adaptations in their anatomy. Their skull, jaws, eyes, and tongue are all uniquely designed to help absorb the impact of the constant pecking and prevent concussions and retinal damage. ๐ The long answer To us humans, banging your head against a wall sounds like a regrettable moment of frustration. To woodpeckers, it sounds like a Tuesday. Source: GIPHY Woodpeckers rapidly peck trees so...
Why does a wooden spoon stop water from boiling over in a pot? This question came from a reader submission (thanks Thomas!). Has a curious question stumped you lately? Feel free to submit your own question here: Submit your question ๐ The short answer Placing a wooden spoon across the top of a pot of boiling starchy foods, like pasta or potatoes, prevents spills by disrupting the bubbles as they rise. The wood's lower temperature and rough surface bursts the bubbles, keeping the foam from...
Why do we say "make a beeline"? This question came from a reader submission (thanks Georgia!). Has a curious question stumped you lately? Feel free to submit your own question here: Submit your question ๐ The short answer The phrase "make a beeline" comes from how honeybees fly directly back to their hive after gathering nectar or return straight to a bountiful food source. ๐ The long answer In the Merriam-Webster Dictionary, you'll find this entry for the word "beeline":...