Why Is Autumn the Best Laboratory a Child Can Have?

Autumn is the best laboratory a child can have, and it comes with no roof, no white coats and no equipment list. The experiments are already set up outside, in the garden, at the edge of the woods and along the walk to school. Most autumn learning activities for kids involve inventing something to do. This season you only have to look. And the strangest experiment of all happens in an ordinary leaf: the yellow you see there in October did not arrive in October.

What makes autumn a laboratory?

A laboratory is a place where you can compare, repeat and change one thing at a time. Autumn offers all three: two leaves from the same tree picked a week apart, a branch you can return to, an apple cut in two with one half in the fridge.

Here is what surprises almost everyone: the yellow in an autumn leaf was there all summer. Green chlorophyll is so strong that it hides the yellow pigments beside it. As days grow shorter and colder, the tree breaks down the chlorophyll and takes the nutrients back into the branch, and the hidden yellow appears. Red is different: many trees make it new in autumn. More on wonder and testing in What is STEAM learning?.

Five experiments autumn has already started

1. Light: around the late-September equinox, days shorten faster than at any other point in autumn.
2. Leaves: an autumn leaf turns dry and crunches between your fingers. Why it falls: September: 7 Changes Children Can See.
3. Fruit: a picked apple is still alive and keeps changing. See Why do garden apples taste different?
4. Decomposers: a mushroom is a small part of a fungus whose threads, called mycelium, live in the soil all year. Look, but never taste.
5. The flock: many birds gather in autumn. See Why do birds fly in flocks?

Try it at home: two leaves, one week

Suitable for: 4-12 years

1. Choose a branch together and tie a loose string around it.
2. Pick one leaf and lay it on white paper.
3. Let the child trace it, colour exactly what they see and write the date.
4. Return to the same branch after one week and pick a new leaf.
5. Lay the new leaf beside last week's drawing.
6. Ask: where did the colour start changing first, at the edge, along the veins or in the middle?

And one more: what happens if you pick one leaf from the very top of the tree and one from the very bottom on the same day? We are not saying a word.

Questions worth wondering about

• Where does the green go when a leaf turns yellow?
• Why do some trees turn red and others only yellow, even when they stand side by side?
• If a fungus lives in the soil all year, how does it "know" it is time to come up, and how could you test that?

Every child is made of good atoms. At Good Atoms we help them discover it. Explore free content at goodatoms.com.

Next time you hold a green leaf, think about the colour hiding inside it.