Friction Makes Heat

Explain why rubbing hands or sliding down a slide makes things warm.

Warm-up, learn, try it together, practice, then a quick check. About 15 minutes.

What children learn in Level 54

Friction happens when two things rub together, and it always makes some heat.
Rub your hands slowly. Now rub them fast and hard. Faster and harder rubbing makes more heat!
Rough surfaces make more friction than smooth ones. That's why striking a match on a rough strip can start it burning.
Try it with a grown-up: rub your hands for 10 seconds slowly, then 10 seconds fast. Which felt warmer?

Georgia Standards of Excellence in Science:

S3P1.a — Ask questions to identify sources of heat energy. (Clarification statement: Examples could include sunlight, friction, and burning.)