Columbia Encyclopedia

(Encyclopedia) complementarity principle, physical principle enunciated by Niels Bohr in 1928 stating that certain physical concepts are complementary. If two concepts are complementary, an experiment that clearly i...

(Encyclopedia) quartzite, usually metamorphic rock composed of firmly cemented quartz grains. Most often it is white, light gray, yellowish, or light brown, but is sometimes colored blue, green, purple, or black by ...

(Encyclopedia) ray, in physics, term denoting the straight line along which light or other form of radiation is propagated from its source. It generally refers to the line of propagation of waves but is also applied...

(Encyclopedia) amplitude ămˈplĭto͞odˌ [key], in physics, maximum displacement from a zero value or rest position. In the harmonic motion of a pendulum, the amplitude of the swing is the greatest distance reache...

(Encyclopedia) mirage mĭräzhˈ [key], atmospheric optical illusion in which an observer sees in the distance a nonexistent body of water or an image, sometimes distorted, of some object or of a complete scene. Exa...

(Encyclopedia)  CE5 Cross section of human eye eye, organ of vision and light perception. In humans the eye is of the camera type, with an iris diaphragm and variable focusing, or accommodation. Other types of ey...

(Encyclopedia) quasar kwāˈsär [key], one of a class of blue celestial objects having the appearance of stars when viewed through a telescope and currently believed to be the most distant and most luminous objects...

(Encyclopedia) Jericho, uninc. town (1990 pop. 13,141), Nassau co., SE N.Y., on Long Island. Chiefly residential, Jericho has some light industries. ...

(Encyclopedia) nimbus nĭmˈbəs [key], in art, the luminous disk or circle or other indication of light around the head of a sacred personage. It was used in Buddhist and other Asian art and by the early Greeks and...

(Encyclopedia) Merrick, uninc. city (1990 pop. 23,042), Nassau co., SE N.Y., on Long Island. Although chiefly residential, it has some light manufacturing. ...