Columbia Encyclopedia

(Encyclopedia) tire, device made of rubber and fabric and attached to the outer rim of a vehicle wheel. Solid rubber tires were in limited use before 1850; they are still used in some special applications, e.g., for...

(Encyclopedia) rapid transit, transportation system designed to allow passenger travel within or throughout an urban area, usually employing surface, elevated, or underground railway systems or some combination of t...

(Encyclopedia) pregnancy, period of time between fertilization of the ovum (conception) and birth, during which mammals carry their developing young in the uterus (see embryo). The average duration of pregnancy in h...

(Encyclopedia)  CE5 Digestive system digestive system, in the animal kingdom, a group of organs functioning in digestion and assimilation of food and elimination of wastes. Virtually all animals have a digestive ...

(Encyclopedia)  CE5 A. AM transmitter B. AM receiver radio, transmission or reception of electromagnetic radiation in the radio frequency range. The term is commonly applied also to the equipment used, especially...

(Encyclopedia) chromatography krōˌmətŏgˈrəfē [key], resolution of a chemical mixture into its component compounds by passing it through a system that retards each compound to a varying degree; a system capabl...

(Encyclopedia)  CE5 A. Canal systems of the three morphological types of sponges B. Internal anatomy of an asconoid sponge, representative of the phylum Porifera Porifera pōrĭfˈərə [key] [Lat.,=pore bearer],...

(Encyclopedia) submarine, naval craft capable of operating for an extended period of time underwater. Submarines are almost always warships, although a few are used for scientific, business, or other purposes (see a...

(Encyclopedia) tunnel, underground passage usually made without removing the overlying rock or soil. Although tunnels are approximately horizontal, they must be built with sufficient gradient for proper drainage. Tu...

(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...