Wheels Down Ramp Go Round and Round
- Students build wheels (made of 2 CDs connected by a pencil as an axle. Held together with clay). Students place play-doh on the CDs in different amounts/areas to make the fastest wheel they can. At the end of class, groups race their wheels.
Concept: Rotational inertia
- Clay (thicker than play-doh)
- pencils (for axles)
- CDs (for wheels)
- cardboard (for ramp)
- Intro to inertia
- Mention inertia a little before beginning
- Ramp outside, and different wheels of different sizes/inertias
- Playing around with clay to modify wheels
- Share equations?
- Ice skater video and other demonstrations
- Learning how to design
Timeline: 0-10 min: Ask if anyone has heard of inertia before.
- - if yes, ask them to explain to the class - otherwise, explain Newton's law: things at rest will stay at rest, and things in motion will stay in motion, unless an outside force acts on them
- -- ex: ice skating with little friction, and inanimate objects not moving around by themselves. -- How much does this force have to be? Depends on inertia: -- Q: If your car breaks down and you have to push it to the gas station, would you rather be pushing a huge truck/Hummer or a small VW bug? -- Q: If you were playing football, would you rather have to stop a child or a sumo wrestler?
10-15: explain activity, split into groups of 4. Go outside if possible.
- - each team gets 4 CDs, 4-5 things of play-doh, some clay, 2 pencils, a ramp.
15-35: working in groups to race their two wheels with different clay orientations to experiment with weight and placement.
35-45: convene, let each group submit their best wheel design for a race.
45-60 min: Discussion
- - Q: While building, what made it faster, what made it slower? - Q: What's important? - A: mass, radius
- If we can figure out how to download one, we'll show a clip of an ice skater pulling in her arms and spinning faster. Reduced inertia, so she can spin faster. If there's a spinny chair in the classroom, one of us can possibly demonstrate. If not, hopefully people have seen/done ice skating or played on tire swings and things and may identify.