Why Do Leaves Change Colors in the Fall?

Why Do Leaves Change Colors in the Fall?


Hi guys! What’s it like outside this time of year
where you live? In our part of the world, the days are getting
shorter, and the weather’s getting cooler, and some of the leaves on the trees are starting
to change colors. This might be happening where you live
too — or it might be happening pretty soon. That’s because we’re heading into one
of the most colorful times of year— autumn! Nothing says autumn or fall like lots of brightly
colored leaves to rake and jump into, or just to pick up and admire. Now, some trees — like pine trees, spruces
and firs — stay green all autumn and winter. But for many of the trees that have leaves,
instead of pointy needles, this time of year means their leaves will turn different shades
of red, orange, and yellow and eventually drop to the ground. Have you ever wondered why this happens? To find out, let’s take a close look at
a green leaf. Leaves on most plants and trees are green
because of a colorful chemical inside them called chlorophyll. Chlorophyll is bright green. But it does more
than just look pretty! It has a special job, because it’s able
to capture the energy that’s in sunlight. Leaves use this light energy to make sugars,
which the tree can then use for its own energy! So chlorophyll is what plants use to make
their own food from sunlight! But! Chlorophyll isn’t the only thing in
tree leaves that gives them color. Leaves have lots of other colorful chemicals — called
pigments — inside them, that are red, yellow, orange, and even purple. If you’ve eaten carrots, cabbage,
or cherries, then you’ve not only seen these pigments, you’ve had them for lunch! All of these colorful pigments have special
jobs, but only chlorophyll helps a plant make the sugar that it needs to live. And since chlorophyll’s job is so important,
there’s way more of it in green leaves than any of the other pigments. In fact, there’s so much chlorophyll that
its green color covers up all of the other colors. Through spring and summer, we don’t see
the red, yellow, and orange pigments in the leaves—we just see the green chlorophyll. But as summer starts to turn into fall,
and the days get shorter, less and less sunlight hits the tree’s leaves … …so the tree starts to make less and less
chlorophyll. Then the leaves become less green, and we’re
able to see more of the other colors that were there all along! And when that starts to happen, you might
want to take the time to enjoy these pretty leaves while you can … because not long
after they turn color, they begin to fall! They fall because, without their chlorophyll
to help them make energy, the leaves don’t really have a job to do. So as winter approaches, the energy that the
leaves have made flows into the tree, and gets stashed away. Then, when the time is just right, they break
off from the branches and fall to the ground. The tree can then live through the winter,
using the energy that it’s saved up, until the days start to get longer and warmer. Then it grows new leaves to capture the sunlight… …and the cycle starts all over again. So when you start to see yellow, orange and
red leaves showing up where you live, remember, those colors were there are all along — — Autumn is just their time to shine! Thanks for joining me on SciShow Kids. What’s
your favorite colored leaf? If you found an extra pretty one, get an adult to help you
take a picture of it and send us an email at kids@scishow.com! And we’ll see you next
time.

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