A lever is a simple machine that consists of a rigid object, such as a rod or beam, pivoted on a fixed point, known as a fulcrum. When a force is applied to the lever, it causes the object to rotate around the fulcrum.

In the case of an egg beater, the rigid object is the handle, and the fulcrum is the point where the handle is attached to the beater. When you turn the handle, the beater rotates around the fulcrum, causing the wires to whisk the eggs.