Spin like an Ice Skater
What you need:
• a spinning chair, like an office chair
Try this:
1. Sit on the chair with your arms stretched out to
the sides. Have someone spin you around and then bring your arms in.
What happens?
2. Try it again with extra weight in your hands. You can use small hand weights or cans of soup.
What’s going on?
The spinning ice skater is a demonstration of conservation of
angular momentum. What do all those big words mean? Conservation means
that it is always the same. Angular means you are spinning and momentum
is a combination of your speed and your inertia (how hard it is to move
you). With your arms out, it’s harder to move you, so you go slower.
With arms in, it is easier to move you and so you go faster.
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Wonders of Physics
University of Wisconsin
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