Columbia Encyclopedia

Search results

500 results found

tungsten

(Encyclopedia)tungsten tŭngˈstən [key] [Swed.,=heavy stone], metallic chemical element; symbol W; at. no. 74; at. wt. 183.84; m.p. about 3,410℃; b.p. 5,660℃; sp. gr. 19.3 at 20℃; valence +2, +3, +4, +5, or...

spear

(Encyclopedia)spear, primitive weapon consisting of a wooden shaft tipped with a sharp point, usually 8 to 9 ft (2.4–2.7 m) in length. The point may be carved from the shaft and hardened in a fire, or made from a...

freezing

(Encyclopedia)freezing, change of a substance from the liquid to the solid state. The temperature at which freezing occurs for a pure crystalline solid is called the freezing point and is a characteristic of the pa...

vaporization

(Encyclopedia)vaporization, change of a liquid or solid substance to a gas or vapor. There is fundamentally no difference between the terms gas and vapor, but gas is used commonly to describe a substance that appea...

tide

(Encyclopedia)tide, alternate and regular rise and fall of sea level in oceans and other large bodies of water. These changes are caused by the gravitational attraction of the moon and, to a lesser extent, of the s...

diminishing returns, law of

(Encyclopedia)diminishing returns, law of, in economics, law stating that if one factor of production is increased while the others remain constant, the overall returns will relatively decrease after a certain poin...

equatorial coordinate system

(Encyclopedia)CE5 Equatorial coordinate system equatorial coordinate system, the most commonly used astronomical coordinate system for indicating the positions of stars or other celestial objects on the celesti...

Death Valley

(Encyclopedia)Death Valley, SE Calif. and SW Nev., a deep, arid basin, 140 mi (225 km) long, bordered on the W by the Panamint Range and on the E by the Amargosa Range. In summer the valley has recorded some of the...

hafnium

(Encyclopedia)hafnium hăfˈnēəm [key], metallic chemical element; symbol Hf; at. no. 72; at. wt. 178.49; m.p. about 2,227℃; b.p. 4,602℃; sp. gr. 13.31 at 20℃; valence +4. Hafnium is a lustrous, ductile, si...

tantalum

(Encyclopedia)tantalum tănˈtələm [key] [from Tantalus], metallic chemical element; symbol Ta; at. no. 73; at. wt. 180.94788; m.p. 2,996℃; b.p. 5,400±100℃; sp. gr. 16.65 at 20℃; valence +2, +3, +4, or +5....