demonstrations:gear_ratios
Gear Ratios
Materials: ★☆☆ Easy to get from supermarket or hardware store
Difficulty: ★☆☆ Can be easily done by most teenagers
Safety: ★☆☆ Minimal safety procedures required
Categories: Simple Machines
Alternative titles: Gears as Simple Machines
Summary
Gears are wheels with teeth that fit together to transfer motion, change speed, or change direction. By connecting large and small gears, you can build a gear train to explore how gears make work easier.
Procedure
- Print and color a gear pattern.
- Tape the pattern to a Styrofoam tray and have an adult cut out the gears.
- Pin the gears to a piece of cardboard so their teeth fit together.
- Turn the big gear slowly and watch how the small gear moves.
- Mark each gear with a colored dot at the top, then count how many turns each gear makes as you spin the big gear.
- Optional: Add a small handle to the big gear to make it easier to turn.
Links
📄 Learn about gears - Home Science Tools: https://learning-center.homesciencetools.com/article/learn-about-gears/
Variations
- Use ridged water bottle caps as simple gears.
- Try gears from building kits like LEGO or K’Nex.
- Experiment with three or more gears to build a gear train with idler gears.
Safety Precautions
- Have an adult cut the Styrofoam with a sharp knife.
- Handle thumbtacks or pins carefully to avoid injury.
Questions to Consider
- Why does the small gear turn faster than the big gear? (Because the smaller gear has fewer teeth, it makes more rotations per turn of the big gear.)
- Why do the gears turn in opposite directions? (Because the teeth push against each other in reverse.)
- How do gears make work easier? (They allow you to trade force for speed, or change the direction of motion.)