Have you ever dived for a ball on the gym floor only to hear a loud screech and feel heat and pain? If so, you probably skinned a hip or a knee and friction was the culprit. Friction is the force created when two surfaces rub together.
- When two smooth surfaces rub together, there is very little friction.
- When two rough surfaces rub together, there is more friction.
- There is less friction when there is a liquid (such as oil) between the two surfaces.
- There is more friction if the two surfaces are forced against each other. Skin against a varnished floor creates a lot of friction (and a nasty injury!).
In many sports and physical activities, equipment is used to increase or decrease friction to the advantage of the participants. Soccer players wear special shoes to increase friction to get good traction, and rock climbers use chalk on their hands. Swimmers wear caps to decrease friction in the water.
Explore the effects of friction with this bobsledding activity, or challenge a friend at three-puck-chuck, where high-friction and low-friction surfaces impede your progress.
