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cloud

(Encyclopedia)CE5 Approximate heights of some types of clouds cloud, aggregation of minute particles of water or ice suspended in the air. Cloudiness (or proportion of the sky covered by any form of cloud),...

explosive

(Encyclopedia)explosive, substance that undergoes decomposition or combustion with great rapidity, evolving much heat and producing a large volume of gas. The reaction products fill a much greater volume than that ...

gold

(Encyclopedia)gold, metallic chemical element; symbol Au [Lat. aurum=shining dawn]; at. no. 79; at. wt. 196.96657; m.p. 1,064.43℃; b.p. 2,808℃; sp. gr. 19.32 at 20℃; valence +1 or +3. Gold is very ductile and...

atomic bomb

(Encyclopedia)atomic bomb or A-bomb, weapon deriving its explosive force from the release of nuclear energy through the fission (splitting) of heavy atomic nuclei. The first atomic bomb was produced at the Los Alam...

balance

(Encyclopedia)balance, instrument used in laboratories and pharmacies to measure the mass or weight of a body. A balance functions by measuring the force of gravity that the earth exerts on an object, i.e., its wei...

diseases of plants

(Encyclopedia)diseases of plants. Most plant diseases are caused by fungi, bacteria, and viruses. Although the term disease is usually used only for the destruction of live plants, the action of dry rot and the rot...

meteorite

(Encyclopedia)meteorite, meteor that survives the intense heat of atmospheric friction and reaches the earth's surface. Because of the destructive effects of this friction, only the very largest meteors become mete...

air pollution

(Encyclopedia)air pollution, contamination of the air by noxious gases and minute particles of solid and liquid matter (particulates) in concentrations that endanger health. The major sources of air pollution are t...

eclipse

(Encyclopedia)CE5 A. Lunar eclipse B. Solar eclipse eclipse ēklĭpsˈ, ĭ– [key] [Gr.,=failing], in astronomy, partial or total obscuring of one celestial body by the shadow of another. Best known are the lu...

mass extinction

(Encyclopedia)mass extinction, the extinction of a large percentage of the earth's species, opening ecological niches for other species to fill. There have been at least ten such events. The five greatest were thos...