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ultrasonics

(Encyclopedia)ultrasonics, study and application of the energy of sound waves vibrating at frequencies greater than 20,000 cycles per second, i.e., beyond the range of human hearing. The application of sound energy...

Wright brothers

(Encyclopedia)Wright brothers, American airplane inventors and aviation pioneers. Orville Wright 1871–1948, was born in Dayton, Ohio, and Wilbur Wright, 1867–1912, near New Castle, Ind. Their interest in aviati...

xenon

(Encyclopedia)xenon zēˈnŏn [key] [Gr.,=strange], gaseous chemical element; symbol Xe; at. no. 54; at. wt. 131.293; m.p. −111.9℃; b.p. −107.1℃; density 5.86 grams per liter at STP; valence usually 0. Xeno...

Roe v. Wade

(Encyclopedia)Roe v. Wade, case decided in 1973 by the U.S. Supreme Court. Along with Doe v. Bolton, this decision legalized abortion in the first trimester of ...

pile

(Encyclopedia)pile, post of timber, steel, or concrete used to support a structure. Vertical piles, or bearing piles, the most common form, are generally needed for the foundations of bridges, docks, piers, and bui...

reservoir

(Encyclopedia)reservoir rĕzˈəvôr, –vwär [key], storage tank or wholly or partly artificial lake for storing water. Building an embankment or dam to preserve a supply of water for irrigation is an ancient pra...

Sinclair, Upton

(Encyclopedia)Sinclair, Upton (Upton Beall Sinclair), 1878–1968, American novelist and socialist activist, b. Baltimore, grad. College of the City of New York, 1897. He was one of the muckrakers, and a dedication...

spinal cord

(Encyclopedia)spinal cord, the part of the nervous system occupying the hollow interior (vertebral canal) of the series of vertebrae that form the spinal column, technically known as the vertebral column. Extending...

ear

(Encyclopedia)CE5 Ear ear, organ of hearing and equilibrium. The human ear consists of outer, middle, and inner parts. The outer ear is the visible portion; it includes the skin-covered flap of cartilage known ...

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...