A Spherometer is a laboratory instrument used to measure the curvature or radius of curvature of spherical surfaces. It consists of a circular plate with three or more legs that are adjustable in height and a central screw or micrometer that can be used to measure the height of the legs. The spherometer is placed on the surface to be measured, and the height of the legs is adjusted until they touch the surface.

The height of the legs is then measured using the central screw or micrometer, and the curvature or radius of curvature of the surface is calculated using a mathematical formula. Spherometers are commonly used in optics experiments to measure the curvature of lenses or mirrors, as well as in metallurgy and material science to measure the radius of curvature of spherical objects such as bearings, gears, and turbine blades.