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antifreeze

(Encyclopedia)antifreeze, substance added to a solvent to lower its freezing point. The solution formed is called an antifreeze mixture. Antifreeze is typically added to water in the cooling system of an internal-c...

phospholipid

(Encyclopedia)phospholipid fŏsˌfōlĭpˈĭd [key], lipid that in its simplest form is composed of glycerol bonded to two fatty acids and a phosphate group. The resulting compound called phosphatidic acid contains...

pH

(Encyclopedia)pH, range of numbers expressing the relative acidity or alkalinity of a solution. In general, pH values range from 0 to 14. The pH of a neutral solution, i.e., one which is neither acidic nor alkaline...

dam

(Encyclopedia)dam, barrier, commonly across a watercourse, to hold back water, often forming a reservoir or lake; dams are also sometimes used to control or contain rockslides, mudflows, and the like in regions whe...

mother-of-pearl

(Encyclopedia)mother-of-pearl or nacre nāˈkər [key], the iridescent substance that forms the lining of the shells of some fresh-water and some salt-water mollusks. Like the pearl it is a secretion of the mantle,...

Frasch process

(Encyclopedia)Frasch process fräsh [key] [for Herman Frasch, the German-American chemist who devised it], process for the extraction of sulfur from subsurface deposits. Three pipes, one inside another, are sunk to...

flat-coated retriever

(Encyclopedia)flat-coated retriever, breed of large sporting dog developed in England in the mid-19th cent. It stands about 23 in. (58 cm) high at the shoulder and weighs about 65 lb (30 kg). Its dense, flat coat o...

sea mouse

(Encyclopedia)sea mouse, marine worm of the genus Aphrodite with a short, broad, segmented body, found in moderately deep water. The upper, or dorsal, surface of a sea mouse bears 15 pairs of raised scales; the spa...

Siloam

(Encyclopedia)Siloam sīlōˈəm [key], pool, SW corner of Jerusalem in the Kidron valley, mentioned in the Bible. A nearby 1,700-foot-long (518 m) tunnel, dating from the time of Hezekiah, diverted water underneat...

oasis

(Encyclopedia)oasis ōāˈsĭs [key], an area within a desert where the water table reaches the surface, with enough moisture to permit the growth of vegetation. The water may come up to the surface in springs, or ...