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expansion

(Encyclopedia)expansion, in physics, increase in volume resulting from an increase in temperature. Contraction is the reverse process. When heat is applied to a body, the rate of vibration and the distances between...

Van Allen radiation belts

(Encyclopedia)CE5 Van Allen radiation belts: The solar wind, a stream of protons, electrons, and ions coming from the sun, gives the belts their asymmetrical shape. Van Allen radiation belts, belts of radiation...

Ottawa, city, Canada

(Encyclopedia)Ottawa ŏtˈəwə [key], city (1991 pop. 313,987), capital of Canada, SE Ont., at the confluence of the Ottawa and Rideau rivers and across the Ottawa from Gatineau, Que. The Rideau Canal separates th...

Heisenberg, Werner

(Encyclopedia)Heisenberg, Werner vĕrˈnər hīˈzənbĕrk [key], 1901–76, German physicist. One of the founders of the quantum theory, he is best known for his uncertainty principle, or indeterminacy principle, ...

Bruno, Giordano

(Encyclopedia)Bruno, Giordano jōrdäˈnō bro͞oˈnō [key], 1548–1600, Italian philosopher, b. Nola. The son of a professional soldier, he entered the Dominican order early in his youth and was ordained a pries...

photocopying

(Encyclopedia)photocopying, process whereby written or printed matter is directly copied by photographic techniques. Generally, photocopying is practical when just a few copies of an original are needed. When many ...

mosque

(Encyclopedia)mosque mŏsk [key], building for worship used by members of the Islamic faith. Muhammad's house in Medina (a.d. 622), with its surrounding courtyard and hall with columns, became the prototype for the...

Florida, state, United States

(Encyclopedia) CE5 Florida ...

silk

(Encyclopedia)silk, fine, horny, translucent, yellowish fiber produced by the silkworm in making its cocoon and covered with sericin, a protein. Many varieties of silk-spinning worms and insects are known, but the ...

nebula

(Encyclopedia)nebula nĕbˈyo͝olə [key] [Lat.,=mist], in astronomy, observed manifestation of a collection of highly rarefied gas and dust in interstellar space. Prior to the 1960s this term was also applied to b...