demonstrations:inertia_hat
Inertia Hat
Materials: ★☆☆ Easy to get from supermarket or hardware store
Difficulty: ★★☆ Can be done by science teachers
Safety: ★☆☆ Minimal safety procedures required
Categories: Motion
Alternative titles: Newton's Inertia Hat
Summary
A wire coat hanger is shaped into a headpiece holding two tennis balls. When balanced on the head, the ball remain still when the person turns.
Procedure
- Use wire cutters to remove the hook from a wire coat hanger.
- Bend the hanger into the shape of the letter “M,” ensuring the center point of the “M” is sharp and well-defined.
- Slightly bend the bottom ends of the “M” upward so they can hold zip ties securely.
- Tape a tennis ball to each end of the “M,” ensuring both balls are the same size and hang below the center point.
- Place the point of the “M” on the top center of your head to balance the hat.
- Spin yourself around while keeping the tennis balls still, or spin the tennis balls around your head while you remain still.
- Observe how inertia keeps the tennis balls in place until friction or another force slows them down.
Links
Inertia Hat (Newton's 1st law) - Kids Fun Science:
📄 Inertia Hat - Morning Science: https://www.astronaut.org/wp-content/uploads/WABI-segment_Challenger_October-10-2016.pdf
Variations
- Try spinning at different speeds to see how long the balls stay still or in motion.
- Use lightweight balls of different sizes to compare inertia.
- Balance the hat on a smooth surface (like a bottle) instead of your head to reduce friction and prolong motion.
Safety Precautions
- Use caution with wire cutters to avoid injury.
- Ensure wire ends are smooth or taped to prevent scratching the head.
- Spin slowly to avoid dizziness or loss of balance.
- Use lightweight objects like tennis balls instead of harder items.
Questions to Consider
- Why do the tennis balls stay at rest even when you spin your body?
- What eventually causes the balls to stop spinning?
- How does this model show Newton’s First Law of Motion (inertia)?
- How does friction between the wire and your head affect the demonstration?