LEVERS

Levers are one of the basic tools that were probably used in prehistoric times. Levers were first described about 260 BC by the ancient Greek mathematician Archimedes (287-212 BC).
A lever is a simple machine that makes work easier for use; it involves moving a load around a pivot using a force. Many of our basic tools use levers, including scissors (2 class 1 levers), pliers (2 class 1 levers), hammer claws (a single class 2 lever), nut crackers (2 class 2 levers), and tongs (2 class 3 levers).

A Type 1 Lever.

A Type 2 Lever.

A Type 3 Lever.

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A Type 1 Lever.

In a Type 1 Lever, the pivot (fulcrum) is between the effort and the load. In an off-center type one lever (like a pliers), the load is larger than the effort, but is moved through a smaller distance. Examples of common tools (and other items) that use a type 1 lever include:

Item		Number of Class 1 Levers Used
see-saw		a single class 1 lever
hammer's claws		a single class 1 lever
scissors		2 class 1 levers
pliers		2 class 1 levers

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A Type 2 Lever.

In a Type 2 Lever, the load is between the pivot (fulcrum) and the effort. Examples of common tools that use a type 2 lever include:

Item		Number of Class 2 Levers Used
stapler		a single class 2 lever
bottle opener		a single class 2 lever
wheelbarrow		a single class 2 lever
nail clippers		Two class 2 levers
nut cracker		Two class 2 levers

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A Type 3 Lever.

In a Type 3 Lever, the effort is between the pivot (fulcrum) and the load. Examples of common tools that use a type 3 lever include:

Item		Number of Class 3 Levers Used
fishing rod		a single class 3 lever
tweezers		Two class 3 levers
tongs		Two class 3 levers