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melting point

(Encyclopedia)melting point, temperature at which a substance changes its state from solid to liquid. Under standard atmospheric pressure different pure crystalline solids will each melt at a different specific tem...

de Gennes, Pierre-Gilles

(Encyclopedia)de Gennes, Pierre-Gilles, 1932–2007, French physicist, Ph.D. Center for Nuclear Studies at Saclay, France, 1958. He was a professor at the Univ. of Paris, Orsay, from 1961 to 1971, when he joined th...

gallium

(Encyclopedia)gallium gălˈēəm [key], metallic chemical element; symbol Ga; at. no. 31; at. wt. 69.723; m.p. 29.78℃; b.p. 2,403℃; sp. gr. 5.904 at 29.6℃ (solid), 6.095 at 29.8℃ (liquid); valence +2 or +3...

freezing

(Encyclopedia)freezing, change of a substance from the liquid to the solid state. The temperature at which freezing occurs for a pure crystalline solid is called the freezing point and is a characteristic of the pa...

naphtha

(Encyclopedia)naphtha năpˈthə, năfˈ– [key], term usually restricted to a class of colorless, volatile, flammable liquid hydrocarbon mixtures. Obtained as one of the more volatile fractions in the fractional ...

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...

latent heat

(Encyclopedia)latent heat, heat change associated with a change of state or phase (see states of matter). Latent heat, also called heat of transformation, is the heat given up or absorbed by a unit mass of a substa...

tear gas

(Encyclopedia)tear gas, gas that causes temporary blindness through the excessive flow of tears resulting from irritation of the eyes. The gas is used in chemical warfare and as a means for dispersing mobs. Compoun...

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 ...

Stevin, Simon

(Encyclopedia)Stevin, Simon sēˈmôn stəvīnˈ [key], 1548–1620, Dutch engineer and mathematician. His experiments in hydrostatics showed that the pressure exerted by a liquid is dependent only on its vertical ...