Friction

Compare how smooth and rough surfaces slow a moving object.

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

What children learn in Level 53

Push a toy car, and it slows down and stops, even with nobody touching it. What force is doing that?
It's friction! Friction is a force between two surfaces that rub together, and it slows moving things down.
Rough surfaces have more friction than smooth ones. A car rolls much farther on a smooth wood floor than on sand.
Friction can help. Shoes grip the ground because of it, and brakes use it to stop a bike.
Try it with a grown-up: roll a toy car down the same ramp onto different surfaces. Measure how far it goes each time.

Georgia Standards of Excellence in Science:

S4P3.a — Plan and carry out an investigation on the effects of balanced and unbalanced forces on an object and communicate the results.