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diffusion

(Encyclopedia)diffusion, in chemistry, the spontaneous migration of substances from regions where their concentration is high to regions where their concentration is low. Diffusion is important in many life process...

exobiology

(Encyclopedia)exobiology or astrobiology, search for extraterrestrial life within the solar system and throughout the universe. Philosophical speculation that there might be other worlds similar to ours dates back ...

silver

(Encyclopedia)silver, metallic chemical element; symbol Ag [Lat. argentum]; at. no. 47; at. wt. 107.8682; m.p. 961.93℃; b.p. 2,212℃; sp. gr. 10.5 at 20℃; valence +1 or +2. Pure silver is nearly white, lustrou...

star

(Encyclopedia)star, hot incandescent sphere of gas, held together by its own gravitation, and emitting light and other forms of electromagnetic radiation whose ultimate source is nuclear energy. The universe co...

cresol

(Encyclopedia)cresol krēˈsōl [key], CH3C6H4OH, any one of three aromatic alcohols present in coal tar. The three compounds are structural isomers; they may be thought of as hydroxy derivatives of toluene or as m...

tellurium

(Encyclopedia)tellurium tĕlo͝orˈēəm [key] [Lat.,=earth], semimetallic chemical element; symbol Te; at. no. 52; at. wt. 127.60; m.p. 450℃; b.p. 990℃; sp. gr. 6.24 at 20℃; valence −2, +4, or +6. Telluriu...

xylene

(Encyclopedia)xylene dīˌmĕthəlbĕnˈzēn [key], C6H4(CH3)2, colorless, oily, liquid aromatic hydrocarbon, used extensively as a solvent, obtained from coal tar, wood tar, and sometimes from petroleum. It is a m...

Fermi, Enrico

(Encyclopedia)Fermi, Enrico ĕnrēˈkō fĕrˈmē [key], 1901–54, American physicist, b. Italy. He studied at Pisa, Göttingen, and Leiden, and taught physics at the universities of Florence and Rome. He contribu...

glycine

(Encyclopedia)CE5 glycine glīˈsēn [key], organic compound, one of the 20 amino acids commonly found in animal proteins. Glycine is the only one of these amino acids that is not optically active, i.e., it does...

Alvarez, Luis Walter

(Encyclopedia)Alvarez, Luis Walter, 1911–88, American physicist, b. San Francisco, grad. Univ. of Chicago, 1932, Ph.D. 1936. He was awarded the 1968 Nobel Prize in Physics for his discovery of a large number of r...