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nucleus, in physics
(Encyclopedia)nucleus, in physics, the extremely dense central core of an atom. Following the discovery of radioactivity by A. H. Becquerel in 1896, Ernest Rutherford identified two types of radiation given off b...pyroclastic flow
(Encyclopedia)pyroclastic flow, turbulent, fluidized mixture of rock, volcanic ash, and hot gas that moves like an avalanche away from a volcanic eruption. A pyroclastic flow may contain a mix of rock fragments ran...precipitation, in chemistry
(Encyclopedia)precipitation, in chemistry, a process in which a solid is separated from a suspension, sol, or solution. In a suspension such as sand in water the solid spontaneously precipitates (settles out) on st...matter
(Encyclopedia)matter, anything that has mass and occupies space. Matter is sometimes called koinomatter (Gr. koinos=common) to distinguish it from antimatter, or matter composed of antiparticles. The atomic th...Duruy, Victor
(Encyclopedia)Duruy, Victor vēktôrˈ dürüēˈ [key], 1811–94, French historian. He was a professor at Reims and Paris, and as minister of public instruction (1863–69) under Napoleon III he encouraged the ad...Head Start
(Encyclopedia)Head Start, U.S. educational program for disadvantaged preschool children, established under the Economic Opportunity Act of 1964. Aimed initially only at poor children, its purpose was to organize pr...Forster, William Edward
(Encyclopedia)Forster, William Edward, 1818–86, British statesman. He entered Parliament as a Liberal in 1861. As vice president of the council in William Gladstone's first ministry (1868–74), he introduced the...Titchener, Edward Bradford
(Encyclopedia)Titchener, Edward Bradford tĭchˈənər [key], 1867–1927, American psychologist, b. Chichester, England, grad. Oxford, 1890. He studied in Leipzig (Ph.D. 1892) under Wundt (whose Principles of Phys...Roscoe, Sir Henry Enfield
(Encyclopedia)Roscoe, Sir Henry Enfield rŏsˈkō [key], 1833–1915, English chemist. He was professor (1857–87) at Owens College, Manchester. He is known for his work, with R. W. Bunsen, in photochemistry and f...public school
(Encyclopedia)public school, in the United States, a tax-supported elementary or high school open to anyone. In England the term was originally applied to grammar schools endowed for the use of the lay public; howe...Browse by Subject
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