Diagram of the use of a first-class lever (blue) on afulcrum (brown)
Alever is a length that canhinge about one point, and that point is known as the fulcrum. Levers have lots of uses, including for weighing things, or for makingforces bigger or smaller, or makingmovements bigger or smaller. All levers feature a fulcrum about which the lever pivots, and depending on the distances from this pivot there will be different amounts of force and of movement. The lever is one of sixsimple machine. There are three types of levers: first-class, second-class and third-class.
The earliest remaining writings about levers are from the 3rd century BC. They were written byArchimedes. "Give me a place to stand, and I shall move the earth." is a famous quote from Archimedes who stated the correct mathematical principle of levers (quoted by Pappus of Alexandria).[1]
There are three kinds of levers. The difference between them is where thefulcrum is and where the forces are acting. If the force is nearer the fulcrum, the force will be bigger, but the movement will be less. If the force is further away from the fulcrum, the force will be smaller, but the movement will be bigger. Levers can therefore make make forces bigger. Or make movements more precise. Or just change the place where a force acts.
A first-class lever is a lever where the fulcrum is in between the effort and resistance (the load). Seesaws and crowbars are examples of first class levers.
