Identification

• A simple machine is a device that changes either the direction or magnitude of applied force. The term is commonly used to describe six devices known to Renaissance mechanical physics. In theory, all complicated machines are composed of parts derived from the Simple Six. However, not all simple machines were included. The hydraulic press, for example, is a simple machine but not part of the Simple Six.
  
  

Types

• The Six Simple Machines are the inclined plane, lever, pulley, screw, wedge, the wheel, and axle. The lever, pulley, and wheel all work through the equilibrium of torques (or twisting.) For example, a lever uses fulcrum to multiply the amount of force used, while also inverting the direction in which it is applied (you push down, the object is raised.) The plane, wedge, and screw are dependent on the vector resolution of forces. An example would be the screw, which uses a helical inclined plane to convert rotational force into linear force.
  
  

Function

• What simple machines all have in common is that they create mechanical advantage. They can all be used to increase the output of force. None of these devices actually create energy, but instead transforms it into more usable directions.
  
  

History

• The idea of the simple machine began with the famous Greek philosopher Archimedes, who discovered the principle of mechanical advantage as applied to the lever, and also studied the screw and pulley. Heron of Alexandria later added the wedge to the ultimate list of six. During the Renaissance, the plane, lever, screw, pulley, and wheel and axle were studied. It was Galileo who added the wedge back to the list to form the Simple Six.
  
  

Considerations

• There is a substantial dispute about whether the Simple Six machines are even six in the first place, aside from the lack of inclusion of hydraulic devices. For example, some scientists insist that the wedge is merely a moving inclined plane.