Newton's rings
In optics, an interference phenomenon seen (using white light) as concentric rings of spectral colours where light passes through a thin film of a transparent medium, such as the wedge of air between a large-radius convex lens and a flat glass plate. With monochromatic light (light of a single wavelength), the rings take the form of alternate light and dark bands. They are caused by interference (interaction) between light rays reflected from the plate and those reflected from the curved surface of the lens.
