Newton's Ring Apparatus, 1 Each

The Newton's Ring Apparatus by United Scientific consists of a plano-convex lens on a flat glass plate, held together by a plastic frame, with three thumbscrews to adjust the pressure between lens and plate. The air gap between the surfaces produces concentric interference rings. Physics instructors use it to demonstrate thin-film interference and, with a traveling microscope, to measure ring diameters for wavelength or curvature calculations.