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laser

(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...

mass, in physics

(Encyclopedia)mass, in physics, the quantity of matter in a body regardless of its volume or of any forces acting on it. The term should not be confused with weight, which is the measure of the force of gravity (se...

Oppenheimer, J. Robert

(Encyclopedia)Oppenheimer, J. Robert ŏpˈənhīˌmər [key], 1904–67, American physicist, b. New York City, grad. Harvard (B.A., 1925), Ph.D. Univ. of Göttingen, 1927. He taught at the Univ. of California and t...

sonar

(Encyclopedia)sonar sōˈnär [key], device used underwater for locating submerged objects and for submarine communication by means of sound waves. The term sonar is an acronym for sound navigation ranging. The mai...

Zeeman effect

(Encyclopedia)Zeeman effect, splitting of a single spectral line (see spectrum) into a group of closely spaced lines when the substance producing the single line is subjected to a uniform magnetic field. The effect...

Bernoulli's principle

(Encyclopedia)CE5 Bernoulli's principle Bernoulli's principle, physical principle formulated by Daniel Bernoulli that states that as the speed of a moving fluid (liquid or gas) increases, the pressure within th...

Chu, Steven

(Encyclopedia)Chu, Steven, 1948–, U.S. physicist and government official, b. St. Louis, Mo., grad. Univ. of Rochester (B.S., A.B. 1970), Univ. of California, Berkeley (Ph.D. 1976). He worked from 1978 at Bell Lab...

catabolism

(Encyclopedia)catabolism kətăbˈəlĭzˌəm [key], subdivision of metabolism involving all degradative chemical reactions in the living cell. Large polymeric molecules such as polysaccharides, nucleic acids, and ...

midsummer day and midsummer night

(Encyclopedia)midsummer day and midsummer night, names given to the feast of the nativity of St. John the Baptist (June 24) and the preceding night (St. John's Eve, June 23). Because midsummer is about the time of ...

planetary science

(Encyclopedia)planetary science or planetology, study of planets and planetary systems as a whole. Planetary science applies the theories and methods of traditional disciplines such as astronomy, geology, physics, ...