Understanding Friction

What Makes Things Stop?

When something moves, like a sled going down a hill, it doesn’t keep going forever. At the bottom of the hill, it slows down and stops. This happens because of friction.

Friction is when two things rub against each other. The ground and the sled rub together, and that slows the sled down. Friction helps things stop safely, like brakes on a bike or when we slide on a playground.

Are you ready to answer questions?

What is friction?

• When things bounce high in the air

• When two things rub together

• When things glow in the dark

Why does a sled stop at the bottom of a hill?

• Because of friction

• Because of the wind

• Because it runs out of energy

What does friction help us do?

• Stop moving

• Go faster

• Jump higher

Which of these is an example of friction?

• A sled rubbing on the ground

• A balloon floating in the air

• A ball rolling down a hill forever

Low friction happens when two surfaces slide or roll past each other easily, with little resistance.

Choose two surfaces where friction is low.

• 
• 
• 
• 

High friction occurs when two surfaces resist motion because they are rough or have a large contact area. It makes objects harder to move.

Choose two surfaces where friction is high.

• 
• 
• 
•