The growth timeline is illustrative. Real plants use different amounts of stored food and survive darkness for different lengths of time.
1What a plant is really doing
A plant has to eat — but it builds its own food
You only need two ideas. Watch each one:
Every living thing needs food
Food is energy. You eat to get it. A plant needs energy too — to grow, to make leaves, just to stay alive. But a plant has no mouth and never swallows a thing.
A leaf is a tiny food factory
Light is the power switch. Flip it on and the leaf takes a gas from the air and water from the roots and builds its own sweet food. Flip it off and the factory makes nothing.
2Two very different things
The drink vs the build
It's easy to mix these up — but a drink and a meal are not the same thing:
The drink
Water climbs up and keeps the plant plump so it doesn't wilt. But water is not food — it carries no energy.
The build
With light, the leaf turns air and water into sugar — and that sugar is the food the plant lives on.
3Your turn — run the factory
Turn the light up and watch the leaf build sugar
Here's the inside of one leaf. Slide the light up and down. Watch the air and water flow in and little drops of sugar get built — fast in bright light, and stopping completely in the dark.
4Now the real test — the dark closet
Two watered plants. One in the dark. Run the days. 🌱
Both plants start with half a tank of stored sugar and get the same water. We move one into a dark closet. Guess what happens at the start, then follow both plants through the days.
Guess before you run the days
Both plants have stored sugar. Right as one moves into darkness, what happens?