Columbia Encyclopedia

Search results

437 results found

Sahara

(Encyclopedia)Sahara səhârˈə [key] [Arab.,=desert], world's largest desert, c.3,500,000 sq mi (9,065,000 sq km), N Africa; the western part of a great arid zone that continues into SW Asia. Extending more than ...

pollution

(Encyclopedia)pollution, contamination of the environment as a result of human activities. The term pollution refers primarily to the fouling of air, water, and land by wastes (see air pollution; water pollution; s...

endocrine system

(Encyclopedia)endocrine system ĕnˈdəkrĭn [key], body control system composed of a group of glands that maintain a stable internal environment by producing chemical regulatory substances called hormones. The end...

iron

(Encyclopedia)iron, metallic chemical element; symbol Fe [Lat. ferrum]; at. no. 26; at. wt. 55.845; m.p. about 1,535℃; b.p. about 2,750℃; sp. gr. 7.87 at 20℃; valence +2, +3, +4, or +6. Iron is biologically s...

hydrogen

(Encyclopedia)hydrogen hīˈdrəjən [key] [Gr.,=water forming], gaseous chemical element; symbol H; at. no. 1; interval in which at. wt. ranges 1.00784–1.00811; m.p. −259.14℃; b.p. −252.87℃; density 0.08...

science

(Encyclopedia)science [Lat. scientia=knowledge]. For many the term science refers to the organized body of knowledge concerning the physical world, both animate and inanimate, but a proper definition would also hav...

hurricane

(Encyclopedia)CE5 View into the eye of a hurricane showing the structure of the surrounding cloud wall hurricane, tropical cyclone in which winds attain speeds greater than 74 mi (119 km) per hr. Wind speeds gu...

pottery

(Encyclopedia)pottery, the baked-clay wares of the entire ceramics field. For a description of the nature of the material, see clay. American art pottery flourished in the first half of the 20th cent., with wor...

nuclear energy

(Encyclopedia)CE5 Graph of binding energy per nucleon as a function of mass number nuclear energy, the energy stored in the nucleus of an atom and released through fission, fusion, or radioactivity. In these pr...

Bonaparte

(Encyclopedia)Bonaparte bwōnäpärˈtā [key], family name of Napoleon I, emperor of the French. Of the second generation of the family the most important was Louis Bonaparte's son, Louis Napoleon, who became e...