Columbia Encyclopedia

Search results

500 results found

chemosynthesis

(Encyclopedia)chemosynthesis, process in which carbohydrates are manufactured from carbon dioxide and water using chemical nutrients as the energy source, rather than the sunlight used for energy in photosynthesis....

fuel

(Encyclopedia)fuel, material that can be burned or otherwise consumed to produce heat. The common fuels used in industry, transportation, and the home are burned in air. The carbon and hydrogen in fuel rapidly comb...

wave, in physics

(Encyclopedia)wave, in physics, the transfer of energy by the regular vibration, or oscillatory motion, either of some material medium or by the variation in magnitude of the field vectors of an electromagnetic fie...

transactinide elements

(Encyclopedia)transactinide elements trănsˌăkˈtənīdˌ [key], in chemistry, elements with atomic numbers greater than that of lawrencium (at. no. 103), the last member of the actinide series. See transuranium ...

Broglie, Maurice, duc de

(Encyclopedia)Broglie, Maurice, duc de, 1875–1960, French physicist; brother of Louis Victor, duc de Broglie. His contributions include notable work on X rays and in atomic physics, radioactivity, and electricity...

fallout

(Encyclopedia)fallout, minute particles of radioactive material produced by nuclear explosions (see atomic bomb; hydrogen bomb; Chernobyl) or by discharge from nuclear-power or atomic installations and scattered th...

transition elements

(Encyclopedia)transition elements or transition metals, in chemistry, group of elements characterized by the filling of an inner d electron orbital as atomic number increases. This includes the elements from titani...

Frascati

(Encyclopedia)Frascati fräskäˈtē [key], town, in Latium, central Italy. Beautifully situated in the Alban ...

Spemann, Hans

(Encyclopedia)Spemann, Hans häns shpāˈmän [key], 1869–1941, German embryologist. He was professor of zoology (1919–35) at the Univ. of Freiburg. By transplanting embryonic tissue to a new location or to ano...

Food and Drug Administration

(Encyclopedia)Food and Drug Administration (FDA), agency of the Public Health Service division of the U.S. Department of Health and Human Services. It is charged with protecting public health by ensuring that foods...