Why do leaves change colour in autumn?

In some countries, trees turn from green to yellow, orange and red before winter. It looks like magic!

But it isn't really magic — it's science. Let's find out the secret hiding inside every leaf. Tap Next to begin! 👉

Leaves are green because of a busy worker

Inside every leaf there is a green colour called chlorophyll (say: KLOR-oh-fill).

Chlorophyll uses sunlight to make food for the tree. That's its job all spring and summer — and it makes the leaf look green.

💡 No chlorophyll = no green. Remember that — it's the key to the whole mystery!

Secret colours hide behind the green

Here's the surprise: yellow and orange colours are already inside the leaf all year! The strong green just covers them up.

👉 Tap each colour to discover the worker hiding inside the leaf.

Autumn sends a message: "Time to rest!"

In autumn, the days get shorter and the air gets colder. The tree senses this and gets ready to rest for winter.

The green fades, and the colours appear!

With shorter days, the tree stops making chlorophyll. The green slowly fades — and now we can finally see the yellow and orange that were hiding all along!

Quick brain check 🧠

A leaf turns yellow in autumn. Why?

So why don't leaves change in Singapore? 🇸🇬

Great question! Singapore is warm and sunny all year. The days stay about the same length, so trees never get the "time to rest" signal.

You solved the autumn mystery!

Here's the whole story in 4 steps:

• 1️⃣ Leaves look green because of chlorophyll, which makes food from sunlight.
• 2️⃣ Yellow and orange colours hide inside the leaf all along.
• 3️⃣ In autumn, shorter, colder days tell the tree to rest.
• 4️⃣ The green fades — so the hidden colours finally show! 🍂

And in warm Singapore, trees stay evergreen all year. 🌴

Well done, young scientist — you really understand nature now! 🌟