6 Simple Machines
By: Keenen Williams
Wheel & Axle
A simple lifting machine consisting of a rope that unwinds from a wheel.
Pulley
A wheel with a grooved rim around which a cord passes.
Screw
A short, slender, sharp-pointed metal pin.
Wedge
A piece of wood, metal, or some other material having one thick end and tapering to a thin edge.