The impingement of a gas jet on a liquid surface has several applications including electric arc furnace steel-making, top blown copper converting, welding and dust removal from the producer gas obtained from biomass gasification. An experimental model has been developed to study the effect of a circular air jet impinging upon a liquid surface. Experiments are conducted with variations in the type of liquid, jet velocity, and separation distance between the nozzle and the liquid surface. Upon jet impingement a cavity (depression) is created on the surface of the liquid. The width and height of this cavity have been determined using sophisticated image processing and edge detection software. The shape of the cavity is either parabolic or Gaussian depending on the conditions of the jet flow and the liquid bath. The shear of the impinging air jet causes recirculatory flow patterns within the liquid that are visualized using aluminum particles as tracers. The measurements show that the previously reported theoretical analysis cannot make accurate predictions of the width and height of the cavity unless surface tension and viscous effects of the liquid are properly accounted for.