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Hassel, Odd
(Encyclopedia)Hassel, Odd ôd häsˈəl [key], 1897–1981, Norwegian chemist, b. Christiania (now Oslo), grad. Oslo Univ. (1920), Ph.D. Univ. of Berlin (1924). After pursuing X-ray crystallographic studies in Germ...pipe smoking
(Encyclopedia)pipe smoking. The habit of smoking various substances probably arose independently in different parts of the world. Herodotus in the 5th cent. b.c. describes the Scythians as inhaling the fumes of bur...phonetics
(Encyclopedia)phonetics fōnĕtˈĭks, fə– [key], study of the sounds of languages from three basic points of view. Phonetics studies speech sounds according to their production in the vocal organs (articulatory...zoology
(Encyclopedia)zoology, branch of biology concerned with the study of animal life. From earliest times animals have been vitally important to man; cave art demonstrates the practical and mystical significance animal...radiochemistry
(Encyclopedia)radiochemistry, chemistry of radioactive substances (see radioactivity). Radioactive isotopes are very useful as tracers to study the mechanisms of complex organic reactions, since even minute amounts...medicinal plants
(Encyclopedia)medicinal plants, plants used as natural medicines. This practice has existed since prehistoric times. There are three ways in which plants have been found useful in medicine. First, they may be used ...Jaspers, Karl
(Encyclopedia)Jaspers, Karl kärl yäsˈpərs [key], 1883–1969, German philosopher and psychopathologist, b. Oldenburg. After receiving his medical degree (1909) he became (1914) lecturer in psychology and in 192...color
(Encyclopedia)color, effect produced on the eye and its associated nerves by light waves of different wavelength or frequency. Light transmitted from an object to the eye stimulates the different color cones of the...gum, colloidal plant substance
(Encyclopedia)gum, term commonly applied to any of a wide variety of colloidal substances somewhat similar in appearance and general characteristics, exuded by or extracted from plants. In this classification, howe...halogen
(Encyclopedia)halogen hălˈəjĕn [key] [Gr.,=salt-bearing], any of the chemically active elements found in Group 17 of the periodic table; the name applies especially to fluorine (symbol F), chlorine (Cl), bromin...Browse by Subject
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