1. A lever is a rigid bar that rotates around a fixed point called a fulcrum and is a simple machine that magnifies force and movement speed. 2. The three main components of a lever are the fulcrum, the effort arm where force is applied, and the resistance arm where the object to be moved is located. 3. There are three types of levers - first class levers have the fulcrum between the effort and resistance arms, second class levers have the resistance arm between the fulcrum and effort arm, and third class levers have the effort arm between the fulcrum and resistance arm.