Published on 25/10/2024 by James Best and Rowan Best

Why Do Leaves Change Colour in Autumn?

Hello there, nature detectives! Have you ever wondered why trees put on such a colourful show in the autumn? It’s like they’re nature’s very own painters, splashing reds, oranges, and yellows all over the place. Let’s uncover the secret behind this awesome autumnal magic!

The Hidden Rainbow Inside Leaves

Guess what? Those beautiful autumn colours aren’t new at all - they’ve been hiding in the leaves all along! Let’s meet the colourful characters in our leaf story:

1. Chlorophyll: The green giant
2. Carotenoids: The yellow and orange sidekicks
3. Anthocyanins: The red and purple surprises

The Green Disappearing Act

During spring and summer, chlorophyll is the boss. It helps leaves make food for the tree and gives them their green colour. But when autumn comes and the days get shorter, something cool happens. The chlorophyll starts to disappear!

Colours Come Out to Play

As the green fades away, guess who comes out to shine? That’s right, the yellow and orange carotenoids! They’ve been there the whole time, just hiding behind the green.

And sometimes, when the weather is just right, leaves make a special red pigment called anthocyanin. It’s like they’re putting on a fancy red costume for their big autumn show!

Why Do Trees Do This?

Trees are ever so clever. When winter is coming, they know it’s time to save energy. Dropping leaves helps them survive the cold months. It’s like they’re putting on a warm coat and taking a long winter nap!

Leaf Detective Activity

Want to be a leaf detective? Here’s a fun way to see the colours hiding in leaves:

1. Collect some green leaves (ask a grown-up first!)
2. Place a leaf under a piece of paper
3. Gently rub a crayon over the paper
4. See the leaf’s texture and maybe even some hidden colours!

The Big Leaf Drop

After the colour show, leaves fall to the ground. But don’t worry! This helps trees conserve energy for spring. Plus, those fallen leaves become food for the soil, helping new plants grow. Nature’s recycling at its best!

Make Your Own Autumn Colours

Let’s do a brilliant experiment to see how leaves make different colours. We’ll use felt-tip pens instead of leaves to make it easier!

You’ll need:

• Coffee filters
• Washable felt-tip pens (green, yellow, orange, red)
• Water
• A small cup

Here’s what to do:

1. Draw a thick line of each colour on the coffee filter, about 2.5 centimetres from the bottom.
2. Put a little water in the cup.
3. Dip just the bottom of the filter in the water.
4. Watch the colours climb up the filter and separate!

This is similar to how different pigments show up in leaves. Brilliant, isn’t it?

Wrap-up

So next time you see those beautiful autumn colours, you’ll know the science behind nature’s amazing art show. Remember, those leaves are waving goodbye to summer and getting ready for winter. And now you know their colourful secret!

Keep exploring the world around you, future scientists. There’s so much amazing stuff to discover right in your own back garden!

Written by James Best and Rowan Best