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Spallanzani, Lazzaro

(Encyclopedia)Spallanzani, Lazzaro lädˈdzärō späl-läntsäˈnē [key], 1729–99, Italian naturalist. He was professor at the universities of Modena (1763–69) and Pavia (from 1769). Spallanzani studied regen...

Le Châtelier's principle

(Encyclopedia)Le Châtelier's principle, chemical principle that states that if a system in equilibrium is disturbed by changes in determining factors, such as temperature, pressure, and concentration of components...

flame

(Encyclopedia)flame, phenomenon associated with the chemical reaction of a gas that has been heated above its kindling temperature with some other gas, usually atmospheric oxygen (see combustion). The heat and ligh...

taxis

(Encyclopedia)taxis tăkˈsĭs [key], movement of animals either toward or away from a stimulus, such as light (phototaxis), heat (thermotaxis), chemicals (chemotaxis), gravity (geotaxis), and touch (thigmotaxis). ...

fog

(Encyclopedia)fog, aggregation of water droplets or ice crystals immediately above the surface of the earth (i.e., a cloud near the ground). A light or thin fog is usually called a mist. Fog may occur when the mois...

welding

(Encyclopedia)welding, process for joining separate pieces of metal in a continuous metallic bond. Cold-pressure welding is accomplished by the application of high pressure at room temperature; forge welding (forgi...

Wien, Wilhelm

(Encyclopedia)Wien, Wilhelm vĭlˈhĕlm vēn [key], 1864–1928, German physicist. He was professor at the universities of Giessen (1899), Würzburg (1900–1920), and Munich (from 1920). He received the 1911 Nobel...

engineering

(Encyclopedia)engineering, profession devoted to designing, constructing, and operating the structures, machines, and other devices of industry and everyday life. Until the Industrial Revolution there were only t...

states of matter

(Encyclopedia)states of matter, forms of matter differing in several properties because of differences in the motions and forces of the molecules (or atoms, ions, or elementary particles) of which they are composed...

linseed oil

(Encyclopedia)linseed oil, amber-colored, fatty oil extracted from the cotyledons and inner coats of the linseed. The raw oil extracted from the seeds by hydraulic pressure is pale in color and practically without ...