String, percussion and wind

Musical instruments fall into three main groups, by the part that vibrates.

String instruments

The violin, sitar, guitar, banjo and cello make their sound when taut strings vibrate.

Percussion instruments

Stretched skins, bars or plates vibrate when struck. The tabla, drum, dholak, rabana, davula, udekkiya and thammattama have skins; the xylophone has bars; cymbals and bells have plates.

Wind instruments

The horanewa, flute, conch, saxophone, trumpet and clarinet make their sound when a column of air vibrates.

Figure to be added

Figures 4.41–4.43 — a sitar, a violin and a guitar; a set of percussion instruments including tabla, drums, a tambourine, a xylophone and cymbals; and wind instruments including a horanewa, a flute, a conch, a saxophone, a horn and a trumpet.

What decides the pitch

Group	The frequency depends on
String	the length of the vibrating string; how tightly it is stretched (its tension); its mass per unit length
Percussion	the area of the skin; its tension
Wind	the length of the air column

Shorter or tighter means higher

Just like the hacksaw blade in Activity 4.4: a shorter string, a tighter string or a shorter air column vibrates at a higher frequency, and so gives a higher pitch.