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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...Urals
(Encyclopedia)Urals or Ural Mountains, E European Russia and NW Kazakhstan, forming, together with the Ural River, the traditional boundary between Europe and Asia and separating the Russian plain from the W Siberi...aviation
(Encyclopedia)aviation, operation of heavier-than-air aircraft and related activities. Aviation can be conveniently divided into military aviation, air transport, and general aviation. Military aviation includes al...mining
(Encyclopedia)mining, extraction of solid mineral resources from the earth. These resources include ores, which contain commercially valuable amounts of metals, such as iron and aluminum; precious stones, such as d...Saint Petersburg, city, Russia
(Encyclopedia)Saint Petersburg, formerly Leningrad, Rus. Sankt-Peterburg, city (1990 est. pop. 5,036,000), capital of the Leningrad region (although not administratively part of it) and the administrative center of...metal
(Encyclopedia)metal, chemical element displaying certain properties by which it is normally distinguished from a nonmetal, notably its metallic luster, the capacity to lose electrons and form a positive ion, and th...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...chemistry
(Encyclopedia)chemistry, branch of science concerned with the properties, composition, and structure of substances and the changes they undergo when they combine or react under specified conditions. Organic chemi...Uzbekistan
(Encyclopedia)CE5 Uzbekistan o͝ozbĕkĭstänˈ [key], Uzbek Ozbekiston, officially Republic of Uzbekistan, republic (2015 est. pop. 29,200,000), 173,552 sq mi (449,500 sq km), central Asia. The republic, which ...Armenia, country, Asia
(Encyclopedia)CE5 Armenia ärmēˈnēə [key], Armenian Hayastan, officially Republic of Armenia, republic (2020 est. pop. 2,963,000), 11,500 sq mi (29,785 sq km), in the S Caucasus....Browse by Subject
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