Columbia Encyclopedia

Search results

168 results found

chain reaction

(Encyclopedia)CE5 Chain reaction: A neutron (n) strikes the uranium nucleus (U-235), causing it to split into fission products A and B and release two neutrons. These neutrons can in turn cause further fissions....

mountain

(Encyclopedia)mountain, high land mass projecting conspicuously above its surroundings and usually of limited width at its summit. Although isolated mountains are not unusual, mountains commonly form ranges, compri...

woodcut and wood engraving

(Encyclopedia)woodcut and wood engraving, prints made from designs cut in relief on wood, in contrast to copper or steel engraving and etching (which are intaglio). The term woodcutting is loosely included within t...

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...

antiviral drug

(Encyclopedia)antiviral drug, any of several drugs used to treat viral infections. The drugs act by interfering with a virus's ability to enter a host cell and replicate itself with the host cell's DNA. Some drugs ...

Bernini, Giovanni Lorenzo

(Encyclopedia)Bernini, Giovanni Lorenzo or Gianlorenzo jōvänˈnē lōrĕnˈtsō, jänlōrĕnˈtsō bĕrnēˈnē [key], 1598–1680, Italian sculptor and architect, b. Naples. He was the dominant figure of the Ita...

arch

(Encyclopedia)CE5 Arches arch, the spanning of a wall opening by means of separate units (such as bricks or stone blocks) assembled into an upward curve that maintains its shape and stability through the mutual...

drug resistance

(Encyclopedia)drug resistance, condition in which infecting bacteria can resist the destructive effects of drugs such as antibiotics and sulfa drugs. Drug resistance has become a serious public health problem, sinc...

Minneapolis

(Encyclopedia)Minneapolis mĭnˌēăpˈəlĭs [key], city (2020 pop. 429,606), seat of Hennepin co., E Minn., at the ...

photosynthesis

(Encyclopedia)photosynthesis fōˌtōsĭnˈthəsĭs [key], process in which green plants, algae, and cyanobacteria utilize the energy of sunlight to manufacture carbohydrates from carbon dioxide and water in the pr...