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growing season

(Encyclopedia)growing season, period during which plant growth takes place. In temperate climates the growing season is limited by seasonal changes in temperature and is defined as the period between the last killi...

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...

tundra

(Encyclopedia)tundra tŭnˈdrə [key], treeless plains of N North America and N Eurasia, lying principally along the Arctic Circle, on the coasts and islands of the Arctic Ocean, and to the north of the coniferous ...

thermometer

(Encyclopedia)thermometer, instrument for measuring temperature. Galileo and Sanctorius devised thermometers consisting essentially of a bulb with a tubular projection, the open end of which was immersed in a liqui...

rhodium

(Encyclopedia)rhodium rōˈdēəm [key], metallic chemical element; symbol Rh; at. no. 45; at. wt. 102.90550; m.p. about 1,966℃; b.p. 3,727±100℃; sp. gr. 12.41 at 20℃; valence +2, +3, +4, +5, or +6. Rhodium ...

Hertzsprung-Russell diagram

(Encyclopedia)CE5 The Hertzsprung-Russell diagram shows the relation between the luminosity and surface temperature (which is related to spectral class, or color) of the stars in the Milky Way. Most stars fall a...

climate

(Encyclopedia)climate, average condition of the atmosphere near the earth's surface over a long period of time, taking into account temperature, precipitation (see rain), humidity, wind, barometric pressure, and ot...

Geysir

(Encyclopedia)Geysir gāˈsĭr [key], hot spring, SW Iceland, c.75 mi (120 km) W of Reykjavík. Although in medieval times it erupted three times daily, weeks now elapse between eruptions. The height and temperatur...

chinook, warm, dry air mass

(Encyclopedia)chinook, warm, dry air mass that descends the eastern slopes of the U.S. and Canadian Rocky Mts. after having lost moisture by condensation over the western slopes. Chinooks occur mainly in winter. Th...

cline

(Encyclopedia)cline, in biology, any gradual change in a particular characteristic of a population of organisms from one end of the geographical range of the population to the other. Gradients of characteristics us...