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blue shift
(Encyclopedia)blue shift or blueshift, in astronomy, the systematic displacement of individual lines in the spectrum of a celestial object toward the blue, or shorter wavelength, end of the visible spectrum. The am...fish curing
(Encyclopedia)fish curing. Methods of curing fish by drying, salting, smoking, and pickling, or by combinations of these processes have been employed since ancient times. On sailing vessels fish were usually salted...sound
(Encyclopedia) CE5 Sound waves: An air pressure wave radiating outward from a loudspeaker is perceived as sound. sound, any disturbance that travels through an elastic medium such as air, ground, or water to be ...relativity
(Encyclopedia)relativity, physical theory, introduced by Albert Einstein, that discards the concept of absolute motion and instead treats only relative motion between two systems or frames of reference. One consequ...aberration of starlight
(Encyclopedia)aberration of starlight, displacement of the apparent path of light from a star, resulting in a displacement of the apparent position of the star from its true position; discovered by the English astr...prospecting
(Encyclopedia)prospecting, search for mineral deposits suitable for mining. Modern prospecting has replaced earlier methods based on chance or superstition (e.g., use of the divining rod) with others based on a sci...echo, in acoustics
(Encyclopedia)echo, reflection of a sound wave back to its source in sufficient strength and with a sufficient time lag to be separately distinguished. If a sound wave returns within 1⁄10 sec, the human ear is in...Brownian movement
(Encyclopedia)Brownian movement or motion, zigzag, irregular motion exhibited by minute particles of matter when suspended in a fluid. The effect has been observed in all types of colloidal suspensions (see colloid...dark matter
(Encyclopedia)dark matter, material that is believed to make up nearly 27% of the mass of the universe but is not readily visible because it neither emits nor reflects electromagnetic radiation, such as light or ra...microphone
(Encyclopedia)microphone, device for converting sound into electrical energy, used in radio broadcasting, recording, and sound amplifying systems. Its basic component is a diaphragm that responds to the pressure or...Browse by Subject
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