Columbia Encyclopedia

Search results

500 results found

paleomagnetism

(Encyclopedia)paleomagnetism, study of the intensity and orientation of the earth's magnetic field as preserved in the magnetic orientation of certain minerals found in rocks formed throughout geologic time. Paleom...

Hall effect

(Encyclopedia)Hall effect, experiment that shows the sign of the charge carriers in a conductor. In 1879 E. H. Hall discovered that when he placed a metal strip carrying a current in a magnetic field, a voltage dif...

Betzig, Robert Eric

(Encyclopedia)Betzig, Robert Eric, 1960–, American physicist, b. Ann Arbor, Mich., Ph.D. Cornell, 1988. Betzig worked at AT&T Bell Laboratories from 1988 to 1996, when he become vice president of research and...

videodisc

(Encyclopedia)videodisc or videodisk, disk used with a special player and television to reproduce both pictures and sound. A videodisc player cannot record television programs off the air for later playback, unlike...

Aub, Max

(Encyclopedia)Aub, Max mäks oup [key], 1903–72, Spanish author, b. Paris. He was educated in Spain where he lived until 1942, when he emigrated to Mexico. His style combines realism with fantasy. He used the Spa...

electromagnet

(Encyclopedia)CE5 Electromagnet electromagnet, device in which magnetism is produced by an electric current. Any electric current produces a magnetic field, but the field near an ordinary straight conductor is ...

induction, in electricity and magnetism

(Encyclopedia)induction, in electricity and magnetism, common name for three distinct phenomena. Electromagnetic induction is the production of an electromotive force (emf) in a conductor as a result of a changing ...

sound recording

(Encyclopedia)sound recording, process of converting the acoustic energy of sound into some form in which it can be permanently stored and reproduced at any time. In 1855 the inventor Leon Scott constructed a devic...

Carnegie Mellon University

(Encyclopedia)Carnegie Mellon University, at Pittsburgh, Pa.; est. 1967 through the merger of the Carnegie Institute of Technology (founded 1900, opened 1905) and the Mellon Institute of Industrial Research (founde...

magnetron

(Encyclopedia)magnetron măgˈnĭtrŏnˌ [key], vacuum tube oscillator (see electron tube) that generates high-power electromagnetic signals in the microwave frequency range. Its operation is based on the combined ...