A wind tunnel is a tube like apparatus or tunnel with varying cross-sections that has man-made wind which is made to blow through it at a certain speed. Scientists and engineers put a model of an airplane in the tunnel and then study the way air moves around the model. By looking at the way this smaller model acts in the wind tunnel, they get a pretty good idea of how a real life-sized airplane of the same design will probably fly. It is a lot easier, cheaper, and safer to build and test a model than to build and fly a real airplane. This report will focus primarily on the design and operation of an open circuit low speed wind tunnels. The components involved in the construction of a typical wind tunnel will be presented and accompanied by brief commentary on the underlying physical processes most influential in determining optimal construction of each component.