Columbia Encyclopedia

Search results

500 results found

Brownian movement

(Encyclopedia)Brownian movement or motion, zigzag, irregular motion exhibited by minute particles of matter when suspended in a fluid. The effect has been observed in all types of colloidal suspensions (see colloid...

Winfrey, Oprah

(Encyclopedia)Winfrey, Oprah, 1954–, African-American television host, actress, and media magnate, b. Kosciusko, Miss., as Orpah Gail Winfrey, grad. Tennessee State Univ. (1976). She began her career as a Nashvil...

xenon

(Encyclopedia)xenon zēˈnŏn [key] [Gr.,=strange], gaseous chemical element; symbol Xe; at. no. 54; at. wt. 131.293; m.p. −111.9℃; b.p. −107.1℃; density 5.86 grams per liter at STP; valence usually 0. Xeno...

Warner Brothers

(Encyclopedia)Warner Brothers, American movie studio executives and producers. Sons of poor E European Jewish immigrants, the brothers were Harry Morris (1881–1958), Albert (1884–1967), Samuel Louis (1887–192...

gear

(Encyclopedia)CE5 Types of gears gear, toothed wheel, cylinder, or cone that transmits motion from one part of a machine to another; it is one of the oldest means of transmitting motion. When the teeth of two g...

audiovisual education

(Encyclopedia)audiovisual education, educational instruction by means of materials that use the senses of sight and hearing to stimulate and enrich learning experiences. The successful use of motion pictures and ot...

crank

(Encyclopedia)crank, mechanical linkage consisting of a bar attached to a pivot at one of its ends in such a way that it is capable of rotating through a complete circle about the pivot. One of the principal uses o...

silver chloride

(Encyclopedia)silver chloride, chemical compound, AgCl, a white cubic crystalline solid. It is nearly insoluble in water but is soluble in a water solution of ammonia, potassium cyanide, or sodium thiosulfate (“h...

Strand, Paul

(Encyclopedia)Strand, Paul, 1890–1976, American photographer, b. New York City. Strand studied under Lewis Hine, who introduced him to Alfred Stieglitz. At Stieglitz's famed “291” gallery, Strand had his firs...

Curtis, Edward Sheriff

(Encyclopedia)Curtis, Edward Sheriff, 1868–1952, American photographer and pioneer ethnographer known for his documentation of Native Americans, b. near Whitewater, Wis. Curtis was obsessed with photography from ...