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Heisenberg, Werner

(Encyclopedia)Heisenberg, Werner vĕrˈnər hīˈzənbĕrk [key], 1901–76, German physicist. One of the founders of the quantum theory, he is best known for his uncertainty principle, or indeterminacy principle, ...

rocket, in aeronautics

(Encyclopedia)CE5 Relative positions of the components of the Saturn V rocket, the U.S. space vehicle used in the moon missions rocket, any vehicle propelled by ejection of the gases produced by combustion of s...

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...

electroencephalography

(Encyclopedia)electroencephalography əlĕkˌtrōĕnsĕfˌəlŏgˈrafē [key], science of recording and analyzing the electrical activity of the brain. Electrodes, placed on or just under the scalp, are linked to a...

Euphrates

(Encyclopedia)Euphrates yo͞ofrāˈtēz [key], Turkish Frat, Arabic Al Furat, river of SW Asia, c.1,700 mi (2,740 km) long, formed by the confluence of the Kara and the Murad rivers, E central Turkey, and flowing g...

ventilation

(Encyclopedia)ventilation, process of supplying fresh air to an enclosed space and removing from it air contaminated by odors, gases, or smoke. Proper ventilation requires also that there be a movement or circulati...

star

(Encyclopedia)star, hot incandescent sphere of gas, held together by its own gravitation, and emitting light and other forms of electromagnetic radiation whose ultimate source is nuclear energy. The universe co...

Great Plains

(Encyclopedia)Great Plains, extensive grassland region on the continental slope of central North America. They extend from the Canadian provinces of Alberta, Saskatchewan, and Manitoba south through W central Unite...

radioactivity

(Encyclopedia)CE5 Effects of a magnetic field on the products of radioactivity CE5 Disintegration series: Radioactive decay of radium-226 into lead-206 radioactivity, spontaneous disintegration or decay of t...

aerodynamics

(Encyclopedia)aerodynamics, study of gases in motion. As the principal application of aerodynamics is the design of aircraft, air is the gas with which the science is most concerned. Although aerodynamics is primar...

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