Archimedes is known as one of the most brilliant mathematicians and scientists of antiquity. The lever principle is considered his discovery. In reality, the lever was known and used centuries before his birth. But he was the first to describe the lever principle by mathematical formulas.
The lever is a simple mechanism. It is a rigid bar which can rotate around a fixed point called support point. Two forces are acting on the lever: active force, which moves the lever and strength force which is the force to be defeated. The distance from the support point in the direction of one of the forces represent the arm of the force.
There are three types of levers:
* Order I lever – this type of lever has the fixed point in the center. A rocking chair is an order I lever. One end lift up an object as much as the other end is pushed.
* Order II lever – this type of lever has the mechanical load in the center. A wheelbarrow is an order II lever. The long handles are the lever arms and the fixed point is the front wheel.
* Order III lever – this type of lever has the force and the mechanical load on the same side of the point of support, with the force in the middle. The effort is always greater than the load (which is a mechanical disadvantage), meaning that always get a smaller force than the one applied. The rod is an order III lever. When you throw the rod, it pivots on the point of support, which is your wrist. One end remains motionless, while the other end flies in the air catching the fish (the moving load).
The lever Archimedes was talking about when he said that with a lever and a fixed point he could move the earth is an order I lever.
