Book 7, Question 53
Why Do Flags Flap and Pinwheels Spin?
You can't see wind, but you can see what it does. Moving air pushes on a flag's fabric and on a pinwheel's blades, so they flap and spin. Flags and pinwheels are wind translators that you can see and hear.
From the book
Page from A Million Whys Book 7
More fun facts
- Wind turbine blades work like an airplane wing.
- When wind flows across a blade, the air pressure on one side drops. That creates lift, and the lift makes the blades spin.
- Windmills turn wind energy into mechanical energy.
- In the Netherlands, windmills have been used for centuries to grind corn, drain land, and cut wood.
- A wind turbine's spinning rotor connects to a generator that makes electricity.
Sources: U.S. Department of Energy, Scientific American
Questions kids ask
How is a pinwheel like a wind turbine?
Both use moving air to spin blades. Big turbines connect that spin to a generator to make electricity.
What were old windmills used for?
In the Netherlands, they ground corn, drained land, and cut wood.