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.
In orchestral and wind band scoring, the flute is placed on the top stave of the score, except in the presence of a piccolo part which would be placed above it. The flutes have several auxiliary instruments, most notably the piccolo. Players of lower chair will usually play auxiliary parts while the principal flutist remains on the standard orchestral C flute, where their expertise is most needed. In a standard modern orchestra, three C flutes are used, with the third flutist playing the piccolo. In the wind ensemble or concert band, however, there may be many flutists on each part. In band music it is common for the flutes to be divided into up to two or three parts, in addition to a separate piccolo part.