All sound comes from vibrations. A string instrument is made of wood, and its strings shake to make the sound. Its hollow body makes the sound louder. A violin is played with a bow, which is a stick with a ribbon of horsehair. You pluck a harp with your fingers.

Most woodwinds have a reed, which is a small piece of cane or wood. A reed shakes when air goes across it. A clarinet has a single reed made from the cane of a type of grass. Air makes the reed shake, and that makes the sound.

A flute has no reed. Its sound comes from air that hits an edge. A player changes the note by opening and closing finger holes. That changes the length of the column of air. The air in the tube shakes.

Brass players buzz their lips into a metal mouthpiece to start the sound. In a wind instrument, a longer tube of air makes a lower note. A tuba has a tube so long that it is curled into loops.

An orchestra has four groups of instruments. The groups are strings, woodwinds, brass and percussion. Drums make sound when they are hit. Other things make sound when they are shaken or scraped. A piano makes sound when felt hammers hit its metal strings. A piano is counted with the percussion family, because of those hammers.

Some flutes were made from bone and ivory. They were found in caves in Germany and are about 40,000 years old. In China, bone flutes were found that are 7,000 to 9,000 years old. They were made from the wing bones of birds.

Words to know

• reed: thin cane
• flute: a wind instrument
• flutes: wind instruments
• percussion: hit instruments
• clarinet: a reed instrument
• woodwinds: a group