Columbia Encyclopedia

Search results

500 results found

polyacrylics

(Encyclopedia)polyacrylics pŏlˌēəkrĭlˈĭks [key], group of thermoplastics that are transparent and highly decorative (see plastic). The polyacrylics, or acrylic plastics, are polymers (and copolymers) of deri...

benzoin

(Encyclopedia)benzoin bĕnzoinˈəm [key], balsamic resin, the dried exudation from the pierced bark of various species of the benzoin tree (Styrax) native to Sumatra, Java, and Thailand; appearing as red-brown to ...

casein

(Encyclopedia)casein kāˈsēn [key], well-defined group of proteins found in milk, constituting about 80% of the proteins in cow's milk, but only 40% in human milk. Casein is a remarkably efficient nutrient, suppl...

sulfur dioxide

(Encyclopedia)sulfur dioxide, chemical compound, SO2, a colorless gas with a pungent, suffocating odor. It is readily soluble in cold water, sparingly soluble in hot water, and soluble in alcohol, acetic acid, and ...

phosphorus

(Encyclopedia)phosphorus fŏsˈfərəs [key] [Gr.,=light-bearing], nonmetallic chemical element; symbol P; at. no. 15; at. wt. 30.97376; m.p. 44.1℃; b.p. about 280℃; sp. gr. 1.82 at 20℃; valence −3, +3, or ...

pyramid, in geometry

(Encyclopedia)CE5 Pyramid pyramid, in geometry, solid figure bounded by a polygon (the base, or directrix) and the surface generated by a moving line (the generator) passing through a fixed point (vertex) and c...

pitot static system

(Encyclopedia)pitot static system pētōˈ [key], device for measuring the rate at which a fluid flows. Among the principal applications of the device are an airspeed indicator for aircraft and a distance and speed...

guanine

(Encyclopedia)guanine gwäˈnēn [key], organic base of the purine family. It was reported (1846) to be in the guano of birds; later (1879–84) it was established as one of the major constituents of nucleic acids....

amino group

(Encyclopedia)amino group, in chemistry, functional group that consists of a nitrogen atom attached by single bonds to hydrogen atoms, alkyl groups, aryl groups, or a combination of these three. An organic compound...

etching

(Encyclopedia)etching, the art of engraving with acid on metal; also the print taken from the metal plate so engraved. In hard-ground etching the plate, usually of copper or zinc, is given a thin coating or ground ...