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drum, in music

(Encyclopedia)CE5 Drums drum, in music, percussion instrument, known in various forms and played throughout the world and throughout history. Essentially a drum is a frame over which one or more membranes or sk...

gyroscope

(Encyclopedia)CE5 Three-frame gyroscope gyroscope jīˈrəskōpˌ [key], symmetrical mass, usually a wheel, mounted so that it can spin about an axis in any direction. When spinning, the gyroscope has special p...

spectral class

(Encyclopedia)CE5 spectral class, in astronomy, a classification of the stars by their spectrum and luminosity. In 1885, E. C. Pickering began the first extensive attempt to classify the stars spectroscopically....

birch

(Encyclopedia)CE5 White birch, Betula papyrifera birch, common name for some members of the Betulaceae, a family of deciduous trees or shrubs bearing male and female flowers on separate plants, widely distribut...

blackbody

(Encyclopedia)blackbody, in physics, an ideal black substance that absorbs all and reflects none of the radiant energy falling on it. Lampblack, or powdered carbon, which reflects less than 2% of the radiation fall...

cephalopod

(Encyclopedia)CE5 Internal anatomy of a squid, Loligo, representative mollusk of the class Cephalopoda cephalopod sĕfˈələpŏdˌ [key], member of the class Cephalopoda, the most highly organized group of mol...

model and modeling

(Encyclopedia)model and modeling, in painting, the use of light and shade to simulate volume in the representation of solids. In sculpture the terms denote a technique involving the use of a pliable material such a...

shock wave

(Encyclopedia)shock wave, wave formed of a zone of extremely high pressure within a fluid, especially the atmosphere, that propagates through the fluid at a speed in excess of the speed of sound. A shock wave is ca...

color index

(Encyclopedia)color index, in astronomy, difference in an object's brightness as recorded between any two well-defined bands of the electromagnetic spectrum by using optical filters of different colors. If blue and...

croup

(Encyclopedia)croup kro͞op [key], acute obstructive laryngitis in young children, usually between the ages of three and six. The manifestations are a high-pitched cough and difficulty in breathing, owing to a spas...