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combining weight

(Encyclopedia)combining weight, the proportion (by weight) in which a chemical element combines with other elements to form compounds. The determination of combining weights was a very important part of early chemi...

Hofstadter, Robert

(Encyclopedia)Hofstadter, Robert, 1915–90, American physicist, b. New York City, Ph.D. Princeton, 1938. He taught at Princeton from 1938 to 1950 and also worked at the National Bureau of Standards during World Wa...

formula weight

(Encyclopedia)formula weight, in chemistry, a quantity computed by multiplying the atomic weight (in atomic mass units) of each element in a formula by the number of atoms of that element present in the formula, an...

thermodynamics

(Encyclopedia)thermodynamics, branch of science concerned with the nature of heat and its conversion to mechanical, electric, and chemical energy. Historically, it grew out of efforts to construct more efficient he...

libido

(Encyclopedia)libido lĭbēˈdō, –bīˈ– [key] [Lat.,=lust], psychoanalytic term used by Sigmund Freud to identify instinctive energy with the sex instinct. For Freud, libido is the generalized sexual energy o...

Compton effect

(Encyclopedia)Compton effect [for A. H. Compton], increase in the wavelengths of X rays and gamma rays when they collide with and are scattered from loosely bound electrons in matter. This effect provides strong ve...

Carnot, Nicolas Léonard Sadi

(Encyclopedia)Carnot, Nicolas Léonard Sadi kärnōˈ [key], 1796–1832, French physicist, a founder of modern thermodynamics; son of Lazare N. M. Carnot. His famous work on the motive power of heat (Réflexions ...

Enewetak

(Encyclopedia)Enewetak, Enewetok, or Eniwetok ĕnĭwēˈtŏk, ĕnēˈwĕtôk [key], circular atoll, central Pacific, one of the Ralik Chain in the Marshall Islands. Enewetak is c.50 mi (80 km) in circumference and...

Bloch, Felix

(Encyclopedia)Bloch, Felix, 1905–83, American physicist, b. Zürich, Switzerland, Ph.D. Univ. of Leipzig, Germany, 1928. He was a professor at Stanford from 1934 until his retirement in 1971. Bloch and Edward Pur...

joule

(Encyclopedia)joule jo͞ol, joul [key], abbr. J, unit of work or energy in the mks system of units, which is based on the metric system; it is the work done or energy expended by a force of 1 newton acting through ...