From Academic Kids
A wind instrument is a member of a family of musical instruments. Wind instruments consist of a tube containing a column of air which is set into vibration by the player blowing into (or over) a mouthpiece set into the end of the tube. The pitch is determined by the length of the tube and hence the length of the vibrating column of air.
A range of notes is obtained by:
- adjusting the effective length of the tube by one of
- opening holes in the side of the tube, or
- valves adding extra lengths of tubing in the middle, or
- lengthening the tube by a sliding mechanism
- getting the column of air to vibrate at different harmonics (see harmonic series).
Wind instruments fall into one of the following categories:
Although brass instruments were originally made of brass and woodwind instruments have traditionally been made of wood, the material used to make the body of the instrument is not always a reliable guide to its family. For example, the saxophone is typically made of brass but is classified as a woodwind instrument due to the fact that it has a reed, while the cornett and serpent, although made of wood (or PVC pipe in the case of modern serpents), are in the family of brass instruments because there is no reed in the instrument; that function is formed by the lips of the person playing it.
A more accurate way to determine whether an instrument is brass or woodwind is to examine how the player produces sound. In brass instruments, the player's lips vibrate, and that causes the air enclosed within the instrument to vibrate. In woodwind instruments, however, the player either causes a reed to vibrate which then agitates the column of air (as in a clarinet or oboe), blows against an edge or fipple (as in a recorder), or blows across an open hole (as in a flute).