Like brass instruments, woodwind instruments are essentially lengths of air in a container. As the name suggests, the container in this case is traditionally made of wood-though modern flutes are made of metal. Originally these wooden pipes were drilled with holes, over which players could place their fingers to change the length of vibrating air and so change the note. Recorders still work this way. Other woodwind instruments, though, nowadays have keys over the holes, which the musician can press to lift.

The flute is the simplest kind of woodwind instrument in regular use. The player blows across a hole on the side of the instrument, as you might blow across the neck of a bottle, and the air inside vibrates.

With other woodwind instruments the air inside is made to vibrate by a vibrating reed. In the case of the oboe-and the bassoon, its lower relative-the reed is placed directly in the player's mouth. In the clarinet it is held in the instrument's mouthpiece.

The flute, the oboe and the clarinet all have a relatively high range, like the violin. They differ in sound because of their different construction. Flutes are among the most ancient instruments, and are found in many parts of the world. Oboes, too, go back a long way. The clarinet, much more recent, was invented in the early eighteenth century.