Worlds of David Darling
Encyclopedia of Science
Home > Encyclopedia of Science

Newton's rings

Newton's rings
Newton's ring, a familiar interference phenomenon, can be seen whenever a transparent object or film closely overlies a reflecting surface. Examples include a convex lens on an optical flat, a film of oil floating on water and, all too frequently, a transparent film in a glass slide mounting. Coherent light (light from a single source) reflected from both sides of a thin air gap or oil film interference with itself, giving rise to a pattern of colored or, for monochromatic light, light and dark fringes.
Newton's rings are colored rings that may be observed round the point of contact of a convex lens and a plane reflecting surface. Newton's rings are caused by the interference effects that occur between light waves reflected at the upper and lower surfaces of the air film separating the lens and the flat surface.

Related category