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atomic weight
(Encyclopedia)atomic weight, mean (weighted average) of the masses of all the naturally occurring isotopes of a chemical element, as contrasted with atomic mass, which is the mass of any individual isotope. Althoug...blizzard
(Encyclopedia)blizzard, winter storm characterized by high winds, low temperatures, and driving snow; according to the official definition given in 1958 by the U.S. Weather Bureau, the winds must exceed 35 mi (56 k...Gulf Stream
(Encyclopedia)Gulf Stream, warm ocean current of the N Atlantic Ocean, off E North America. It was first described (1513) by Spanish explorer Ponce de León. The Gulf Stream originates in the Gulf of Mexico and, as...echo, in acoustics
(Encyclopedia)echo, reflection of a sound wave back to its source in sufficient strength and with a sufficient time lag to be separately distinguished. If a sound wave returns within 1⁄10 sec, the human ear is in...Brownian movement
(Encyclopedia)Brownian movement or motion, zigzag, irregular motion exhibited by minute particles of matter when suspended in a fluid. The effect has been observed in all types of colloidal suspensions (see colloid...phosphorescence
(Encyclopedia)phosphorescence fŏsˌfərĕsˈəns [key], luminescence produced by certain substances after absorbing radiant energy or other types of energy. Phosphorescence is distinguished from fluorescence in th...malleability
(Encyclopedia)malleability, property of a metal describing the ease with which it can be hammered, forged, pressed, or rolled into thin sheets. Metals vary in this respect; pure gold is the most malleable. Silver, ...McLennan, Sir John Cunningham
(Encyclopedia)McLennan, Sir John Cunningham, 1867–1935, Canadian physicist, grad. Univ. of Toronto (B.A., 1892; Ph.D., 1900). He taught at the Univ. of Toronto from 1892 to 1932, was professor of physics from 190...sintering
(Encyclopedia)sintering, process of forming objects from a metal powder by heating the powder at a temperature below its melting point. In the production of small metal objects it is often not practical to cast the...specific gravity
(Encyclopedia)specific gravity, ratio of the weight of a given volume of a substance to the weight of an equal volume of some reference substance, or, equivalently, the ratio of the masses of equal volumes of the t...Browse by Subject
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