Columbia Encyclopedia

Search results

500 results found

photoelectric cell

(Encyclopedia)CE5 Photoelectric cell: Light causes a photosensitive surface to emit electrons, which flow as current to the positive terminal. A galvanometer measures the current and thus indicates light intensi...

air conditioning

(Encyclopedia)CE5 Cross section of air conditioning unit. air conditioning, mechanical process for controlling the humidity, temperature, cleanliness, and circulation of air in buildings and rooms. Indoor air i...

bicameral system

(Encyclopedia)bicameral system bīkămˈərəl [key], governmental system dividing the legislative function between two chambers, an “upper,” such as the U.S. Senate and the British House of Lords, and a “low...

magic, in entertainment

(Encyclopedia)magic, in entertainment, the seeming manipulation and supernatural control of the natural world for the amusement and amazement of an audience. Entertainment magic can be divided into four main catego...

interference

(Encyclopedia)CE5 Constructive interference: Two crests or two troughs meet and combine (A, B, C). Destructive interference: A crest and a trough meet and cancel each other (D, E, F). interference, in physics, ...

Wagner, Richard

(Encyclopedia)Wagner, Richard vägˈnər [key], 1813–83, German composer, b. Leipzig. Wagner's second wife, Cosima Wagner, 1837–1930, was the daughter of Liszt and the comtesse d'Agoult. From 1857 to 1870 sh...

mercantilism

(Encyclopedia)mercantilism mûrˈkəntĭlĭzəm [key], economic system of the major trading nations during the 16th, 17th, and 18th cent., based on the premise that national wealth and power were best served by inc...

recognition

(Encyclopedia)recognition, acknowledgment of the admission of new states into the international community by political action of states that are already members. Its derivation is found in the policy of the older E...

naturalization

(Encyclopedia)naturalization, official act by which a person is made a national of a country other than his or her native one. In some countries naturalized persons do not necessarily become citizens but may merely...

amyotrophic lateral sclerosis

(Encyclopedia)amyotrophic lateral sclerosis (ALS) āˌmīətrōfˈik, sklĭrōˈsĭs [key] or motor neuron disease, sometimes called Lou Gehrig's disease, degenerative disease that affects motor neurons in the brai...