Bow (music)

In music, a bow is a device pulled across the strings of a string instrument in order to make them vibrate and emit sound.

A bow typically consists of a length of wood with some other material stretched between its ends. Rosin which is sticky and made from tree sap needs to be regularly applied to the bow hair, so that the bow moving across the instrument's strings will cause the string to vibrate and produce a tone. Bows used in other cultures often stretch a single piece of string between the ends of the wood.

Fine modern bows used to play orchestral string instruments of the violin family(the violin, viola, cello and double bass) are usually made of Pernambuco wood from Brazil, and strung with horse-hair. Other parts of a fine modern bow are traditionally made with silver or gold, ebony wood from Africa, ivory, pearl shell, leather, and sometimes tortoise shell. Fine synthetic bows are also made of fiberglass and other man made materials. Cheaper bows can also be made of synthetic materials and less suitable types of wood. The correct number of horse hairs a bow maker or luthier uses to hair and rehair bows for violin family instruments is 150 hairs for each bow. Inexpensive bows often use nylon or synthetic hair.

The kind of bow in use today was brought into its modern form largely by the bow-maker François Tourte in 19th century France. Pernambuco wood which was imported into France to make textile dye, was found by the early french bow masters to have just the right combination of strength, resiliency, weight, and beauty. Even so, a violin or a bow maker must choose sound quality above all, when choosing wood to make bows and instruments. A common practice even today, is to reserve the best and most beautiful tone wood for bows and instruments for a makers most expensive works.In order to shape the curve or “cambre” of the bow stick, a maker must first carve and then gradually heat the stick. A metal or wooden template is used to get the exact models curve and shape while heating. The art of bow making has changed little since the 19th century.

Playing an instrument with the wood of the bow rather than the hair or string is known by the Italian phrase col legno. “Arco” in Italian is the indication to use the bow hair to create the sound. The characteristic long, sustained, and singing sound produced by the violin, viola, violoncello, and double bass is due to the drawing of the bow against their strings. This sustaining of musical sound with a bow is comparable to a singer using breath to sustain sounds and sing long, smooth, or “legato” melodies. Without the bow the violin family would have a more percussive, plucked, or “pizzicato” character, like the guitar.