What is Friction?

Research Reading
LI:Reading for meaning and understanding.

Friction is actually a force that appears whenever two things rub against each other. Although two objects might look smooth, microscopically, they're very rough and jagged.

Every time you go up a steep hill it feels like you are going to fall down the hill. Air resistance is a big concern of designers of cars, planes,and boats.

These designers try to reduce friction so that a car will travel across the road,a plane will fly through the air,and a boat will move through the water as easily as possible.

You can slide much faster down the water slide because water reduces friction.