Levers are used to lift heavy weights with the least amount of effort. In the example opposite, the heavy weight on the left hand side is been lifted by the person because of the lever. The longer the 'rod' the easier it is to lift the weight. Under normal circumstances the person would not be able to lift the weight at all. The fulcrum is the place where the rod pivots (or rotates).

The load is the scientific name for the weight. The effort is quite simply the amount of effort used to push down on the rod in order to move the weight.

We use levers in every day life. Bicycle brakes work due to the fact that they are based on a lever. The diagram opposite shows the fulcrum and the effort.

Another good example of a lever is a simple door handle or a wheel barrow.

THREE CLASSES OF LEVER

There are three classes of lever and each class has fulcrum, load and effort which together can move a heavy weight.

CLASS 1

The workman uses a trolley to move the large packing case. The fulcrum is the wheel.

CLASS 2

CLASS 3

The fisherman catches the fish which becomes the load at the end of the lever.

Draw your own examples of the three classes of lever. Think in terms of examples that you have used at home, work or school.

How did the Egyptians use levers to build the pyramids ?

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