A machine makes work easier by changing at least one of three factors:

There are six kinds of simple machines:

A slanting surface connecting a lower level to a higher level. Example:

An object with at least one slanting side ending in a sharp edge, which cuts materials apart. Examples:

A slanting surface wrapped around a pole, which holds things together or lifts materials. Examples:

A stiff bar that rests on a support called fulcrum, which lifts or moves loads. Examples:

A round object with a rod through its center, which lifts or moves loads. Examples:

A simple machine that uses grooved wheels and a rope to raise, lower, or move a load. Examples: