1. Simple Machines

2.  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).

3.  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).

4.  A Type 1 Lever. A Type 2 Lever. A Type 3 Lever.

5. 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. 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 Examples of common tools (and other items) that use a type 1 lever include: Examples of common tools (and other items) that use a type 1 lever include:

6.  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 Examples of common tools that use a type 2 lever include:

7. Item Number of Class 3 Levers Used fishing rod a single class 3 lever tweezers Two class 3 levers tongs Two class 3 levers Examples of common tools that use a type 3 lever include: