It is said to be that Archimedes was the first person to figure out how to use a lever.Archimedes is a great inventor and probally invented some of the stuff you use in you're life today.Archimedes alsoi invented some other simple machines.
A lever is a bar that is free to turn about a fixed point. Levers are just one of the six facinating simple machines. But when you say simple, don't just think simple. Some aspects about the simple machine, the lever, may be difficult for you to understand. Let me introduce you to the aspects of levers.

There are three different kinds of levers. They are the first class,second class,and third class levers. The only difference between the three is the location of the fulcrum, or piveting point.

A first class lever is like your everyday crowbar. The fulcrum is in the middle with the resistance force, the load, on one end and the effort force on the other.

An example of a second class lever is a wheelbarrow. On a second class lever the fulcrum is on the end, the resistance force, the load, is in the middle,and the effort is at the other end.

A baseball bat is an example of a third class lever .The fulcrum is on the end of one side, the effort force is in the middle, and the resistance force, the load, is at the the top.
No one really knows when the term "lever" was first used to describe this simple machine. However, it was Archimedes, the great thinker, inventor, and mathematician, who stated around 240 BC, "Give me a lever long enough and a place to stand and I will move the earth."