The speed of sound is the distance travelled per unit time by a sound wave as it propagates through an elastic medium. In dry air at 20 Â°C (68 Â°F), the speed of sound is 343.2 metres per second (1,126 ft/s; 1,236 km/h; 768 mph; 667 kn), or a kilometre in 2.914 s or a mile in 4.689 s. The speed of sound in an ideal gas depends only on its temperature and composition. The speed has a weak dependence on frequency and pressure in ordinary air, deviating slightly from ideal behavior.
A flute is a musical instrument that produces sound when a stream of air is directed against the edge of a hole, causing the air within the body of the instrument to vibrate. Most flutes are tubular, but some are globular or other shapes.
The first known use of the word flute was in the 14th century. According to the Oxford English Dictionary, this was in Geoffrey Chaucer's The Hous of Fame, c.1380.