Columbia Encyclopedia

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smog

(Encyclopedia)smog smŏg [key] [smoke+fog], dense, visible air pollution. Smog is commonly of two types. The gray smog of older industrial cities like London and New York derives from the massive combustion of coal...

New Delhi

(Encyclopedia)New Delhi dĕlˈē [key], city (1991 pop. 294,149), capital of India and of the National Capital Territory of Delhi, N central India, on the right bank of the Yamuna River. Predominantly an administra...

acid rain

(Encyclopedia)acid rain or acid deposition, form of precipitation (rain, snow, sleet, or hail) containing high levels of sulfuric or nitric acids (pH below 5.5–5.6). Produced when sulfur dioxide and various nitro...

Windsor, cities, Canada

(Encyclopedia)Windsor wĭnˈzər [key]. 1 Town (1991 pop. 3,625), central N.S., Canada, at the mouth of the Avon River on an arm of Minas Basin. It is the center of a gypsum and limestone-quarrying area. Manufactur...

wheel and axle

(Encyclopedia)CE5 Wheel and axle wheel and axle, simple machine consisting of a wheel mounted rigidly upon an axle or drum of smaller diameter, the wheel and the axle having the same axis. It is fundamentally a...

Manhattan Project

(Encyclopedia)Manhattan Project, the wartime effort to design and build the first nuclear weapons (atomic bombs). With the discovery of fission in 1939, it became clear to scientists that certain radioactive materi...

Columbia, cities, United States

(Encyclopedia)Columbia kəlŭmˈbēə [key]. 1 City (2020 pop. 104,681), Howard co., central Md., between W...

asbestos, mineral

(Encyclopedia)asbestos, common name for any of a variety of silicate minerals within the amphibole and serpentine groups that are fibrous in structure and more or less resistant to acid and fire. Chrysotile asbesto...

amplifier

(Encyclopedia)amplifier, device that accepts a varying input signal and produces an output signal that varies in the same way as the input but has a larger amplitude. The input signal may be a current, a voltage, a...

inclined plane

(Encyclopedia)CE5 Inclined plane inclined plane, simple machine, consisting of a sloping surface, whose purpose is to reduce the force that must be applied to raise a load. To raise a body vertically a force mu...