Episode Details

Every fall, the leaves turn orange and yellow and red and we all stop and stare.

But where do those colors actually come from? And why does it only happen in autumn?

In this episode Daniel is standing outside looking at the trees when he asks the question — and what he and Mom figure out together changes the way you'll look at fall color for the rest of your life.

Here's the first thing that surprises most people. The orange and yellow colors were already in the leaf all summer long. They were never created by fall. The green just covered them up. Leaves are green because of a pigment called chlorophyll — and chlorophyll is so dominant during the warmer months that it completely hides everything else underneath.

Then fall arrives. The days get shorter. The tree starts sensing there isn't enough sunlight to keep making food the same way. So it stops producing chlorophyll. And as the green slowly fades — the orange and yellow that were waiting underneath finally get to show themselves.

They were there the whole time. Just waiting for the green to leave.

But the reds are a completely different story. Unlike the oranges and yellows — which were hiding all along — the reds are brand new. As the tree starts shutting down, it seals off the connection between the leaf and the branch. That traps sugars inside the leaf. And those trapped sugars help the leaf produce a brand new red pigment called anthocyanin. On bright sunny fall days the conditions are just right for the most vivid reds — which is why the same tree can look completely different from one year to the next depending on the weather.

So the same leaf is doing two different things at once. Revealing what was hidden. And creating something new.

But here's the part Daniel figures out that neither of them saw coming. The tree isn't dying. It's being incredibly organized. Before dropping each leaf, the tree pulls all the valuable nutrients back out — nitrogen, phosphorus, everything useful — and stores them in the trunk and branches for spring. The color change isn't the story. It's a side effect of the tree doing its accounting.

Daniel's description of what that means for raking season is the last line of the episode.

What you'll find in this episode:

• Why the orange and yellow were hiding in the leaf all summer
• Why the reds are completely different and how they're actually made
• Why bright sunny fall days often produce the most vivid colors
• What the tree is actually doing when the colors change — and why it isn't dying
• Daniel's "doing its accounting" line — and what it means for anyone holding a rake

Short, beautiful, and the kind of episode that makes an ordinary walk outside feel like something completely different.

Listen, wonder, and learn.

Find us @smilewithDaniel everywhere.