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hygrometer

(Encyclopedia)hygrometer hīgrŏmˈətər [key], instrument used to measure the moisture content of a gas, as in determining the relative humidity of air. The temperature at which dew or frost forms is a measure of...

gluon

(Encyclopedia)gluon, an elementary particle that mediates, or carries, the strong, or nuclear, force. In quantum chromodynamics (QCD), the quantum field theory of strong interactions, the interaction of quarks (to ...

cesium

(Encyclopedia)cesium sēˈzēəm [key] [Lat.,=bluish gray], a metallic chemical element; symbol Cs; at. no. 55; at. wt. 132.90545; m.p. 28.4℃; b.p. 669.3℃; sp. gr. 1.873 at 20℃; valence +1. Cesium is a ductil...

Tahiti

(Encyclopedia)Tahiti tähēˈtē [key], island (2002 pop. 169.674), South Pacific, in the Windward group of the Society Islands, French Polynesia. The capital is Papeete. Tahiti is the largest (402 sq mi/1,041 sq k...

technetium

(Encyclopedia)technetium tĕknēˈshēəm [key] [Gr. technetos=artificial], artificially produced radioactive chemical element; symbol Tc; at. no. 43; mass no. of most stable isotope 98; m.p. 2,200℃; b.p. 4,877�...

pump

(Encyclopedia)pump, device to lift, transfer, or increase the pressure of a fluid (gas or liquid) or to create a vacuum in an enclosed space by the removal of a gas (see vacuum pumps under vacuum). The centrifugal ...

Rajasthan

(Encyclopedia)Rajasthan räˈjəstän [key], state (2001 provisional pop. 56,473,122), 132,150 sq mi (342,269 sq km), NW India, bordered on the west by Pakistan. The capital is Jaipur; other large cities are Ajmer,...

seaborgium

(Encyclopedia)seaborgium sēbôrˈgēəm [key], artificially produced radioactive chemical element; symbol Sg; at. no. 106; mass number of most stable isotope 271; m.p., b.p., sp. gr., and valence unknown. Situated...

stellar populations

(Encyclopedia)stellar populations, two broadly contrasting distributions of star types that are characteristic of different parts of a galaxy. Population I stars are young, recently formed stars, whereas population...

Chlorophyta

(Encyclopedia)Chlorophyta klōrŏfˈətə [key], phylum (division) of the kingdom Protista consisting of the photosynthetic organisms commonly known as green algae. The organisms are largely aquatic or marine. The ...