A mirror is a highly reflective surface. However, a normal household mirror will reflect light differently than a "perfect" mirror utilized for scientific purposes. Both types of mirrors are created using glass with a reflective coating.

A household mirror is manufactured using a plane of glass with a polished coating of aluminum or silver. The practical application of this object in a domestic setting is to reflect an image of oneself for visual inspection of clothing or application of beauty products, or to place on a wall in order to make a room appear larger.

A ray of light interacting with a plane mirror will obey predictably. The angle of incidence will equal the angle of reflection relative to the normal, but some of the light will be absorbed by the mirror. It will also reflect light from many directions.

A "perfect" or a type of dielectric mirror, on the other hand, reflects over 99% of the light directed at it. They can be created to reflect specific wavelengths of light, and are utilized in equipment, such as lasers.