A windy afternoon sends Raven's paper map flapping. Rocket chases his cap across the field.
"This morning the breeze barely moved the leaves," Raven says. "Now it is pushing everything around. What do you notice?"
Rocket points at a tall white wind turbine on the hill. Its blades are spinning fast today.
Nova hums beside them. "Here is a clue," she says. "Wind is moving air. Think about this week's big idea."
Wind is moving air, so it has motion energy.
A gentle breeze barely moves a leaf. A strong, fast wind can push you and bend trees.
Wind turbines use their blades to collect the wind's motion energy.
The spinning blades turn a machine called a generator, which makes electricity.
Stored energy can turn into motion energy too.
When you ride a bike down a hill, stored energy from being high up changes into motion energy.
The higher and heavier something is, the more of this stored energy it has.
That is why a bike can speed up going downhill without pedaling.
Think about two identical bikes. One rolls slowly. One zooms fast.
The fast bike has more motion energy. It is harder to stop.
That is one reason people slow down near others.
Less speed means less energy in a bump.
| Statement | True or false? |
|---|---|
| Wind is moving air, so it has motion energy. | ? |
| A wind turbine's blades turn a generator. | ? |
| A bike going downhill turns stored energy into motion energy. | ? |
| A gentle breeze has more energy than a strong, fast wind. | ? |
What a week of discoveries! Tomorrow is Launch Lab, a speed test with your family.