Optics is the study of the properties and behavior of light. In this section you can learn about everything from holograms to lasers and lenses.

Range Finder

Range Finder, an optical instrument for measuring distance. Range finders are used mainly in photography for focusing cameras and in gunnery for aiming artillery.

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  • Color


    Color, a class of sensations made by light on the optic nerve. All colors--whether seen in nature or applied by man with pigments through painting, dyeing, or printing--are caused by light and the way light affects the eyes. See more »

  • How do one-way mirrors work?

    How do one-way mirrors work?

    Just about everyone has seen a television show or movie in which a criminal suspect is questioned while detectives watch from behind a one-way mirror. How does a piece of glass manage to reflect light from one side while remaining clear on the other? See more »

  • How does a Fresnel lens work?

    How does a Fresnel lens work?

    I have a thin piece of plastic mounted on the back window of my RV. It magnifies things so I can see better when I'm backing up. How can such a thin piece of plastic magnify things? A regular glass magnifying lens would have to be curved on both sides and much thicker. See more »

  • Illusion


    Illusion, an impression of a real stimulus, received through one of the senses, which does not agree with other sense impressions or with objective tests. See more »

  • Lens


    Lens, a curved, transparent body (usually of glass) that refracts (bends) light rays. See more »

  • Light


    Light, the form of radiant energy that makes vision possible. Since sight is the most important of the senses, light furnishes most of the information we have about our surroundings. See more »

  • Mirror


    Mirror, a smooth, polished surface that reflects light rays and causes images to be formed. See more »

  • Optics


    Optics, the branch of physics that deals with all aspects of visible light, including vision, and with infrared and ultraviolet radiation. See more »

  • Photometry


    Photometry, the measurement of the intensity of light and the illumination it produces. See more »

  • Rainbow


    Rainbow, an arc or circle of light of different colors, caused by the refraction and reflection of sunlight by drops of water. See more »

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