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physical chemistry
(Encyclopedia)physical chemistry, branch of science that combines the principles and methods of physics and chemistry. It provides a fundamental theoretical and experimental basis for all of chemistry, including or...porcelain
(Encyclopedia)porcelain [Ital. porcellana], white, hard, permanent, nonporous pottery having translucence which is resonant when struck. Porcelain was first made by the Chinese to withstand the great heat generated...dissociation
(Encyclopedia)dissociation, in chemistry, separation of a substance into atoms or ions. Thermal dissociation occurs at high temperatures. For example, hydrogen molecules (H2) dissociate into atoms (H) at very high ...compression
(Encyclopedia)compression, external stress applied to an object or substance, tending to cause a decrease in volume (see pressure). Gases can be compressed easily, solids and liquids to a very small degree if at al...germination
(Encyclopedia)germination, in a seed, process by which the plant embryo within the seed resumes growth after a period of dormancy and the seedling emerges. The length of dormancy varies; the seed of some plants (e....Stirling engine
(Encyclopedia)Stirling engine, an external combustion reciprocating engine having an enclosed working fluid that is alternately compressed and expanded to operate a piston, thus converting heat from a variety of so...luminism
(Encyclopedia)luminism lo͞oˈmĭnĭzˌəm [key], American art movement of the 19th cent. Luminism was an outgrowth of the Hudson River school. In its concern for capturing the effects of light and atmosphere it is...homelessness
(Encyclopedia)homelessness, the condition of not having a permanent place to live, widely perceived as a societal problem only beginning in the 1980s. Figures for the number of homeless people in the United States ...harrow, in agriculture
(Encyclopedia)harrow, farm implement, consisting of a wooden or metal framework bearing metal disks, teeth, or sharp projecting points, called tines, which is dragged over plowed land to pulverize the clods of eart...angelfish
(Encyclopedia)angelfish, common name for certain members of the Pomacanthidae, a family of brightly colored reef-dwelling tropical fishes with compressed bodies and small mouths and teeth. They were formerly classi...Browse by Subject
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