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carbon cycle

(Encyclopedia)CE5 Carbon cycle carbon cycle, in biology, the exchange of carbon between living organisms and the nonliving environment. Inorganic carbon dioxide in the atmosphere is converted by plants into sim...

physics

(Encyclopedia)physics, branch of science traditionally defined as the study of matter, energy, and the relation between them; it was called natural philosophy until the late 19th cent. and is still known by this na...

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...

lightning

(Encyclopedia)lightning, electrical discharge accompanied by thunder, commonly occurring during a thunderstorm. The discharge may take place between one part of a cloud and another part (intracloud), between one cl...

mineral

(Encyclopedia)mineral, inorganic substance occurring in nature, having a characteristic and homogeneous chemical composition, definite physical properties, and, usually, a definite crystalline form. A few of the mi...

kitchen

(Encyclopedia)kitchen, separate room or other space set aside for the cooking or preparation of meals. When cooking first moved indoors, it was performed, with other domestic labors, in the common room, where the f...

vanadium

(Encyclopedia)vanadium vənāˈdēəm [key], metallic chemical element; symbol V; at. no. 23; at. wt. 50.9415; m.p. about 1,890℃; b.p. 3,380℃; sp. gr. about 6 at 20℃; valence +2, +3, +4, or +5. Vanadium is a ...

Poitier, Sir Sidney

(Encyclopedia)Poitier, Sir Sidney, 1927–2022, Bahamian-American actor, b. Miami, raised in the Bahamas, returned to the United States at 14. Poitier served in the 1...

printer

(Encyclopedia)printer, device that reproduces text, images, or other data from a computer, digital camera, smartphone, or the like on paper or another medium. Impact printers, which mostly have been superseded by i...

fuel cell

(Encyclopedia)fuel cell, electric cell in which the chemical energy from the oxidation of a gas fuel is converted directly to electrical energy in a continuous process (see oxidation and reduction). The efficiency ...