Columbia Encyclopedia

Search results

382 results found

Hubble Space Telescope

(Encyclopedia)Hubble Space Telescope (HST), the first large optical orbiting observatory. Built from 1978 to 1990 at a cost of $1.5 billion, the HST (named for astronomer E. P. Hubble) was expected to provide the c...

induction, in logic

(Encyclopedia)induction, in logic, a form of argument in which the premises give grounds for the conclusion but do not necessitate it. Induction is contrasted with deduction, in which true premises do necessitate t...

Agent Orange

(Encyclopedia)Agent Orange, herbicide used by U.S. forces during the Vietnam War to expose enemy guerrilla forces in forested areas. Agent Orange contains varying amounts of dioxin. Exposure to the defoliant has be...

school vouchers

(Encyclopedia)school vouchers, government grants aimed at improving education for the children of low-income families by providing school tuition that can be used at public or private schools. The idea behind schoo...

programmed instruction

(Encyclopedia)programmed instruction, method of presenting new subject matter to students in a graded sequence of controlled steps. Students work through the programmed material by themselves at their own speed and...

Bush, George Walker

(Encyclopedia)Bush, George Walker, 1946–, 43d President of the United States (2001–9), b. New Haven, Conn. The eldest son of President George H. W. Bush, he was was raised in Texas and, like his father, attende...

econometrics

(Encyclopedia)econometrics, technique of economic analysis that expresses economic theory in terms of mathematical relationships and then tests it empirically through statistical research. Econometrics attempts to ...

Grateful Dead, The

(Encyclopedia)Grateful Dead, The, American rock music group formed in 1965 by guitarists Jerry Garcia, 1942–95, and Bob Weir, 1947–, harmonica player Ron “Pigpen” McKernan, 1945–73, bassist Phil Lesh, 194...

urinalysis

(Encyclopedia)urinalysis yo͝orˌənălˈĭsĭs [key], clinical examination of urine for the purpose of medical diagnosis. Urine is initially examined for such characteristics as color, odor, and specific gravity. ...

phosphate

(Encyclopedia)phosphate, salt or ester of phosphoric acid, H3PO4. Because phosphoric acid is tribasic (having three replaceable hydrogen atoms), it forms monophosphate, diphosphate, and triphosphate salts in which ...