Q:

# Why does friction occur?

A:

Friction is caused by the bumps on the surface of one object colliding with the bumps of another object's surface. All surfaces have bumps, created by their molecular structure. These bumps may only be visible on objects with seemingly smooth surfaces through the use of a microscope.

Know More

## Keep Learning

There are two types of friction: static and kinetic. Static friction occurs when objects are not moving. The resistance encountered when trying to push a heavy object across a surface is an example of static friction. Kinetic friction occurs as two objects rub against each other. Kinetic friction produces energy in the form of heat.

Sources:

## Related Questions

• A:

To create a science fair project about wheels reducing friction, the exhibitioner could give live demonstrations of how difficult it is to push identical objects across a surface with and without wheels. Friction is the resistance of a body to motion in contact with another body and is directly proportional to the contact area between two surfaces; wheeled bodies move more smoothly over surfaces because their contact areas are reduced.

Filed Under:
• A:

Surface tension is caused by the attraction between liquid molecules along the surface of the liquid. Most of the molecules in a liquid have several neighboring molecules that they interact with, but the molecules along the surface have no neighboring molecules above them, which increases the strength of the surface molecules with each other.

Filed Under:
• A:

Friction is a force that opposes motion, so it is unhelpful in all situations where the motion of an object is desired. A by-product of friction is that energy is wasted in the form of heat, which can cause problems in temperature-sensitive environments.