Music is an art form and cultural activity whose medium is sound organized in time. The common elements of music are pitch (which governs melody and harmony), rhythm (and its associated concepts tempo, meter, and articulation), dynamics (loudness and softness), and the sonic qualities of timbre and texture (which are sometimes termed the "color" of a musical sound). Different styles or types of music may emphasize, de-emphasize or omit some of these elements. Music is performed with a vast range of instruments and vocal techniques ranging from singing to rapping; there are solely instrumental pieces, solely vocal pieces (such as songs without instrumental accompaniment) and pieces that combine singing and instruments. The word derives from Greek μουσική (mousike; "art of the Muses"). See glossary of musical terminology.
In physics, sound is a vibration that typically propagates as an audible wave of pressure, through a transmission medium such as a gas, liquid or solid.
A thousand trills and quivering sounds In airy circles o'er us fly, Till, wafted by a gentle breeze, They faint and languish by degrees, And at a distance die.
Sonorous metal blowing martial sounds, At which the universal host up sent A shout that tore hell's concave, and beyond Frighted the reign of Chaos and old Night.
John Milton, Paradise Lost (1667; 1674), Book I, line 540.
EU-funded scientists successfully developed a system that generates electricity from low-temperature waste heat ranging from 60 to 120 °C. Harnessing low-grade heat should help to significantly mitigate the negative environmental impact of industrial plants.