What is friction?
Whenever objects rub against each other there is a tiny force between them that is trying to stop the movement, this is called friction. Friction is a force that always acts in the opposite direction to the object.
When we try to walk in water there is a force that is going against us making it difficult. That force is friction. This also happens on land when we’re walking, there is a force between our feet and the ground. It doesn’t feel as strong as in the water but it gives our feet grip.
Rougher surfaces produce more friction and smoother surfaces produce less. That’s why sliding on a rough carpet is much more difficult than sliding on a smooth wooden floor.
Facts about friction
- Cyclists crouch down low on their bicycles to reduce the air resistance (a type of friction). This helps them cycle faster.
- Slippery substances like oil reduce the friction between two surfaces.
- Wheels couldn’t work without friction.
- Liquid acts like a barrier between surfaces, creating less friction. This is why it’s harder for a car to stop on a wet road than a dry one.
- Friction can generate electricity.
- The harder you press two surfaces together, the more force is needed to overcome the friction and get them to slide.
- When a match is lit, friction is caused by rubbing the match against the rough surface of the box. This friction creates enough heat to ignite a chemical compound in the match head.
- Fluid friction is used in water parks to make slides smoother.