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laser

(Encyclopedia)CE5 Ordinary light sources produce incoherent light, while a laser produces a beam of coherent light. laser [acronym for light amplification by stimulated emission of radiation], device for the cr...

bee

(Encyclopedia)bee, name for flying insects of the superfamily Apoidea, in the same order as the ants and the wasps. Bees are characterized by their enlarged hind feet, typically equipped with pollen baskets of stif...

acids and bases

(Encyclopedia)acids and bases, two related classes of chemicals; the members of each class have a number of common properties when dissolved in a solvent, usually water. Another theory that provides a very broad ...

fire fighting

(Encyclopedia)fire fighting, the use of strategy, personnel, and apparatus to extinguish, to confine, or to escape from fire. Ancient Rome is known to have had a fire department consisting by the 1st cent. of app...

isomer

(Encyclopedia)isomer īˈsəmər [key], in chemistry, one of two or more compounds having the same molecular formula but different structures (arrangements of atoms in the molecule). Isomerism is the occurrence of ...

embryo

(Encyclopedia)CE5 Development of the human embryo embryo ĕmˈbrēō [key], name for the developing young of an animal or plant. In its widest definition, the embryo is the young from the moment of fertilizatio...

sulfuric acid

(Encyclopedia)sulfuric acid, chemical compound, H2SO4, colorless, odorless, extremely corrosive, oily liquid. It is sometimes called oil of vitriol. Although sulfuric acid is now one of the most widely used c...

airplane

(Encyclopedia)CE5 A. Side view of jet-propelled airplane B. Top view airplane, aeroplane, or aircraft, heavier-than-air vehicle, mechanically driven and fitted with fixed wings that support it in flight thro...

earth, in geology and astronomy

(Encyclopedia)CE5 A. Cross section of the earth, showing its shells B. Detailed cross section of the crust and upper mantle: The lithosphere consists of the hard rock in the crust and upper mantle, lying above t...

nutrition

(Encyclopedia)nutrition, study of the materials that nourish an organism and of the manner in which the separate components are used for maintenance, repair, growth, and reproduction. Nutrition is achieved in vario...