Friction & Surfaces
Compare how things move on different surfaces, noticing that some surfaces create more friction than others
What a learner can do afterwards
- Observe and compare how the same object moves on at least three different surfaces
- Describe that rough surfaces slow objects down more than smooth surfaces
- Use the word 'friction' to explain why movement differs on different surfaces
The lesson
You already know that pushes and pulls make things move. Friction is a force too, but it works the other way. It happens when two surfaces rub together, and it slows movement down or stops it. Every surface makes some friction, but some surfaces make a lot more than others.
Leo pushes his toy car across the thick carpet in his bedroom. It only rolls a little way before stopping. Then he pushes it just as hard across the smooth wood floor in the hallway. This time it rolls much farther. The carpet is bumpy and rough, so it grips the wheels and creates a lot of friction. The wood floor is smooth, so it creates less friction and lets the car keep rolling.
Look closely at a surface to guess how much friction it makes. Rough surfaces, like carpet, sand, or gravel, have lots of tiny bumps that catch and slow things down. Smooth surfaces, like polished wood, tile, or ice, have far fewer bumps, so things slide across them more easily.
Rough surfaces make more friction and slow things down; smooth surfaces make less friction and let things move farther.
Watch it
Where it sits
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.