Columbia Encyclopedia

Search results

500 results found

free energy

(Encyclopedia)free energy or Gibbs free energy, quantity derived from the relationships between heat and work studied in thermodynamics and used as a measure of the relative stability of a physical or chemical syst...

Meiji restoration

(Encyclopedia)Meiji restoration, The term refers to both the events of 1868 that led to the “restoration” of power to the emperor and the entire period of revolutionary changes that coincided with the Meiji emp...

calorie

(Encyclopedia)calorie, abbr. cal, unit of heat energy in the metric system. The measurement of heat is called calorimetry. The calorie, or gram calorie, is the quantity of heat required to raise the temperature of ...

Safavid

(Encyclopedia)Safavid säfäˈwēd [key], Iranian dynasty (1499–1736), that established Shiite Islam in Iran as an official state religion. The Safavid state provided both the territorial and societal foundations...

solar wind

(Encyclopedia)solar wind, stream of ionized hydrogen—protons and electrons—with an 8% component of helium ions and trace amounts of heavier ions that radiates outward from the sun at high speeds. The continuous...

radiometer

(Encyclopedia)radiometer rāˌdēŏmˈətər [key], instrument for detection or measurement of electromagnetic radiation; the term is applied in particular to devices used to measure infrared radiation. One of the ...

rayon

(Encyclopedia)rayon, synthetic fibers made from cellulose or textiles woven from such fibers; more rayon is manufactured than any other synthetic fiber. The name was adopted (1924), in preference to “artificial s...

spectrum

(Encyclopedia)CE5 Dispersion of white light by a triangular prism spectrum, arrangement or display of light or other form of radiation separated according to wavelength, frequency, energy, or some other propert...

Girondists

(Encyclopedia)Girondists zhērôNdăNˈ [key], political group of moderate republicans in the French Revolution, so called because the central members were deputies of the Gironde dept. Girondist leaders advocated ...

noise pollution

(Encyclopedia)noise pollution, human-created noise harmful to health or welfare. Transportation vehicles are the worst offenders, with aircraft, railroad stock, trucks, buses, automobiles, and motorcycles all produ...