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uranium

(Encyclopedia)uranium yo͞orāˈnēəm [key], radioactive metallic chemical element; symbol U; at. no. 92; mass number of most stable isotope 238; m.p. 1,132℃; b.p. 3,818℃; sp. gr. 19.1 at 25℃; valence +3, +4...

electricity

(Encyclopedia)CE5 Electrical and radio symbols electricity, class of phenomena arising from the existence of charge. The basic unit of charge is that on the proton or electron—the proton's charge is designate...

lava

(Encyclopedia)lava läˈvə [key], molten rock that erupts on the earth's surface, either on land or under the ocean, by a volcano or through a fissure. It solidifies into igneous rock that is also called lava. Bef...

silicon

(Encyclopedia)silicon, nonmetallic chemical element; symbol Si; at. no. 14; interval in which at. wt. ranges 28.084–28.086; m.p. 1,410℃; b.p. 2,355℃; sp. gr. 2.33 at 25℃; valence usually +4. Silicon is the ...

sodium chloride

(Encyclopedia)sodium chloride, NaCl, common salt. Salt is important in many ways. It is an essential part of the diet of both humans and animals and is a part of most animal fluids, such as blood, sweat, and te...

water supply

(Encyclopedia)water supply, process or activity by which water is provided for some use, e.g., to a home, factory, or business. The term may also refer to the supply of water provided in this way. In the United Sta...

Neptune, in astronomy

(Encyclopedia)Neptune, in astronomy, 8th planet from the sun at a mean distance of about 2.8 billion mi (4.5 billion km) with an orbit lying between those of Uranus and the dwarf planet Pluto; its period of revolut...

arsenic

(Encyclopedia)arsenic ärˈsənĭk [key], a semimetallic chemical element; symbol As; at. no. 33; at. wt. 74.92160; m.p. 817℃ (at 28 atmospheres pressure); sublimation point 613℃; sp. gr. (stable form) 5.73; va...

molybdenum

(Encyclopedia)molybdenum məlĭbˈdənəm [key] [Gr.,=leadlike], metallic chemical element; symbol Mo; at. no. 42; at. wt. 95.96; m.p. about 2,617℃; b.p. about 4,612℃; sp. gr. 10.22 at 20℃; valence +2, +3, +4...

cosmic rays

(Encyclopedia)cosmic rays, charged particles moving at nearly the speed of light reaching the earth from outer space. Primary cosmic rays consist mostly of protons (nuclei of hydrogen atoms), some alpha particles (...