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stellar evolution

(Encyclopedia)CE5 The above Hertzsprung-Russell (H-R) diagram shows the track of stellar evolution for a typical star. After spending much of its life evolving toward or along the main sequence, the star becomes...

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...

Al Aziziyah

(Encyclopedia)Al Aziziyah ăzĭzēˈä [key], town, NW Libya, near Tripoli. It is a major trade center of the Jifarah plain. Al Aziziyah was long considered to have recorded the highest shade temperature on earth, ...

deliquescence

(Encyclopedia)deliquescence dĕlˌəkwĕsˈəns [key], conversion of a solid substance into a liquid as a result of absorption of water vapor from the air. Since impurities in a solid lower its melting point, the a...

oxygen tent

(Encyclopedia)oxygen tent, device used to maintain a patient in an oxygen-rich environment. The oxygen tent is composed of a clear plastic sheet suspended over the bed and tucked beneath the mattress to provide an ...

Solvay process

(Encyclopedia)Solvay process [for Ernest Solvay], commercial process for the manufacture of sodium carbonate (washing soda). Ammonia and carbon dioxide are passed into a saturated sodium chloride solution to form s...

liquid air

(Encyclopedia)liquid air, ordinary air that has been liquefied by compression and cooling to extremely low temperatures (see liquefaction). Its commercial preparation involves purification by washing to remove solu...

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 ...

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...