Here's why:

* One Movement: Levers operate with a single pivot point (fulcrum) and require only one movement of the input force to produce output force.

* Changes Size and Direction of Force: Levers can amplify or reduce the force applied (change the size of the force) and can change the direction of the force.

Examples of levers:

* Crowbar: A crowbar is a good example of a lever that amplifies force and changes its direction. The force you apply to one end is amplified at the other end to lift a heavy object.

* See-saw: A see-saw is a lever that demonstrates the change in force direction. The force you apply downward on one side is transformed into an upward force on the other side.

Let me know if you'd like to explore other simple machines that might fit your description!