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convection

(Encyclopedia)convection, mode of heat transfer in fluids (liquids and gases). Convection depends on the fact that, in general, fluids expand when heated and thus undergo a decrease in density (since a given volume...

altitude

(Encyclopedia)altitude, vertical distance of an object above some datum plane, such as mean sea level or a reference point on the earth's surface. It is usually measured by the reduction in atmospheric pressure wit...

ionosphere

(Encyclopedia)ionosphere īŏnˈəsfēr [key], series of concentric ionized layers forming part of the upper atmosphere of the earth from around 30 to 50 mi (50 to 80 km) to 250 to 370 mi (400 to 600 km) where it m...

hydrology

(Encyclopedia)hydrology, study of water and its properties, including its distribution and movement in and through the land areas of the earth. The hydrologic cycle consists of the passage of water from the oceans ...

Gay-Lussac, Joseph Louis

(Encyclopedia)Gay-Lussac, Joseph Louis zhôzĕfˈ lwē gā-lüsäkˈ [key], 1778–1850, French chemist and physicist. He was professor in Paris at the Sorbonne, at the Polytechnic School, and at the Jardin des Pla...

phase diagram

(Encyclopedia)CE5 Phase diagram for a substance, like water, which expands on freezing phase diagram, graph that shows the relation between the solid, liquid, and gaseous states of a substance (see states of ma...

snowball earth

(Encyclopedia)snowball earth, hypothesized condition in which the earth was covered completely by ice during several periods in the Proterozoic. The hypothesis was originally developed to explain evidence of the co...

rainmaking

(Encyclopedia)rainmaking, production of rain by artificial means now generally disregarded, though it is probable that rainmaking hastens or increases rainfall from clouds suitable for natural rainfall. Interest in...

El Niño–Southern Oscillation

(Encyclopedia)El Niño–Southern Oscillation (ENSO) ĕl nēnˈyō [key], large-scale climatic fluctuation of the tropical Pacific Ocean and the overlying atmosphere. The El Niño [Span.,=the child] is the South Am...

Mars, in astronomy

(Encyclopedia)Mars, in astronomy, 4th planet from the sun, with an orbit next in order beyond that of the earth. Mars has two natural satellites, discovered by Asaph Hall in 1877. The innermost of these, Phobos...