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drugs

(Encyclopedia)drugs, substances used in medicine either externally or internally for curing, alleviating, or preventing a disease or deficiency. At the turn of the century only a few medically effective substances ...

water

(Encyclopedia)CE5 A. Water molecule (black circles represent valence-shell electrons) B. Structure of ice: Each oxygen atom (white circles) is bonded to four other oxygen atoms by hydrogen bonds, the hydrogen at...

carbon

(Encyclopedia)CE5 The three solid forms of pure carbon: In the diamond crystal each carbon atom is surrounded symmetrically by four other carbons (at each of the four corners of a tetrahedron). In the graphite c...

Africa

(Encyclopedia)CE5 Africa ăfˈrĭkə [key], second largest continent (2015 est. pop. 1,194,370,000), c.11,677,240 sq mi (30,244,050 sq km) including adjacent islands. Broad to the north (c.4,600 mi/7,400 km wide...

fire fighting

(Encyclopedia)fire fighting, the use of strategy, personnel, and apparatus to extinguish, to confine, or to escape from fire. Ancient Rome is known to have had a fire department consisting by the 1st cent. of app...

Oman

(Encyclopedia)CE5 Oman ōmänˈ [key], officially Sultanate of Oman, independent sultanate (2015 est. pop. 3,287,000), c.82,000 sq mi (212,380 sq km), SE Arabian peninsula, on the Gulf of Oman and the Arabian Se...

Industrial Revolution

(Encyclopedia)Industrial Revolution, term usually applied to the social and economic changes that mark the transition from a stable agricultural and commercial society to a modern industrial society relying on comp...

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...

piracy

(Encyclopedia)piracy, robbery committed or attempted on the high seas. It is distinguished from privateering in that the pirate holds no commission from and receives the protection of no nation but usually attacks ...

nutrition

(Encyclopedia)nutrition, study of the materials that nourish an organism and of the manner in which the separate components are used for maintenance, repair, growth, and reproduction. Nutrition is achieved in vario...