What a leaf gives out
Show on a big screenA water plant sits in a jar, near a bright lamp. Tiny bubbles rise. What are they?
- A water plant sits in a clear jar of water.
- A lamp shines close by. Many bubbles rise from the leaves.
- Move the lamp farther away. Fewer bubbles rise.
- The bubbles have oxygen in them.
The idea
The bubbles have oxygen in them, a gas the leaves make.
Glucose is a simple sugar. It gives the plant quick energy.
A lamp can be used instead of the Sun. A closer lamp gives more light. More light gives more bubbles, because the leaf makes more oxygen.
The rule
A leaf in sunlight gives out oxygen. It also makes glucose, a sugar for quick energy. Extra glucose is stored as starch.
Lamps and water are risky together. Ask a teacher to set it up.
A lamp warms the water. A teacher keeps the jar cool.
Watch out!
Beyond a certain brightness, a brighter lamp adds no more bubbles.
Now try it. Guess first. Then move the lamp closer. Count the bubbles.
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Try the lab to finish this lesson.