In physics, a mirror is a reflective surface that bounces light (or other electromagnetic radiation) back, forming an image. Mirrors are typically made of a smooth material, like glass, coated with a thin layer of metal (like silver or aluminum) on one side. This metal coating is what reflects the light. The type of image formed depends on the shape of the mirror: Plane mirrors (flat surfaces) produce virtual, upright, and laterally inverted images of the same size as the object. Curved mirrors (spherical or parabolic) can produce magnified or reduced, real or virtual, and inverted or upright images. Concave mirrors converge light, while convex mirrors diverge light.