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harmonic

(Encyclopedia)harmonic. 1 Physical term describing the vibration in segments of a sound-producing body (see sound). A string vibrates simultaneously in its whole length and in segments of halves, thirds, fourths, e...

Moseley, Henry Gwyn Jeffreys

(Encyclopedia)Moseley, Henry Gwyn Jeffreys mōzˈlē [key], 1887–1915, English physicist, grad. Trinity College, Oxford, 1910. He began his research under Ernest Rutherford while serving as lecturer at the Univ. ...

multiple sclerosis

(Encyclopedia)multiple sclerosis (MS), chronic, slowly progressive autoimmune disease in which the body's immune system attacks the protective myelin sheaths that surround the nerve cells of the brain and spinal co...

oilbird

(Encyclopedia)oilbird, common name for an owllike, cave-dwelling bird, Steatornis caripensis, belonging to the family Steatornithidae. It spends its days in dark caves, maneuvering by means of a batlike sonar devic...

United States Naval Observatory

(Encyclopedia)United States Naval Observatory, a federal astronomical observatory, located in Washington, D. C. It evolved from the Navy's oldest scientific institution, the Depot of Charts and Instruments, founded...

photon

(Encyclopedia)photon fōˈtŏn [key], the particle composing light and other forms of electromagnetic radiation, sometimes called light quantum. The photon has no charge and no mass. About the beginning of the 20th...

electricity

(Encyclopedia)CE5 Electrical and radio symbols electricity, class of phenomena arising from the existence of charge. The basic unit of charge is that on the proton or electron—the proton's charge is designate...

modem

(Encyclopedia)modem [modulator/demodulator], an external device or internal electronic circuitry used to transmit and receive digital data over a communications line normally used for analog signals. A modem attach...

Tavener, Sir John Kenneth

(Encyclopedia)Tavener, Sir John Kenneth tăvˈənər, –nə [key], 1944–2013, English composer, b. London; studied Royal Academy of Music. Tavener, whose work shows a consistent but evolving tonal or modal style...

interference

(Encyclopedia)CE5 Constructive interference: Two crests or two troughs meet and combine (A, B, C). Destructive interference: A crest and a trough meet and cancel each other (D, E, F). interference, in physics, ...