STRINGS - The four major instruments in the string family, the violin, the viola, the cello and the double bass, are built the same way. The instruments are made of many pieces of wood which are glued - never nailed - together. The body of the instrument is hollow, thus becoming a resonating box for the sound. Four strings (sometimes five on the double-bass) made of animal gut, nylon, or steel are wrapped around pegs at one end of the instrument and attached to a tailpiece at the other. They are stretched tightly across a bridge to produce their assigned pitches.
WOODWINDS - When these instruments were first made they were made out of wood, which is why it is called the Woodwind Family. Today, a combination of materials is used including wood, metal, and plastic. They share the common shape of narrow cylinders or pipes with a mouthpiece at the top and an opening at the bottom end. Sound is made by blowing air through the mouthpiece and you change the pitch by opening or closing the holes using your fingers. Besides the flute, the holes of most woodwind instruments are covered by keys.
BRASS Family instruments produce their unique sound by the player buzzing his/her lips while blowing air through a cup or funnel shaped mouthpiece. To produce higher or lower pitches, the player adjusts the opening between his/her lips. The brass family can trace its ancestry back to herald French horns, hunting horns, and military bugles. The main instruments of the brass family include the trumpet, trombone, French horn, and tuba. As with other instrument families, the shorter the tubing length, the higher the sound and the longer the tubing length, the lower the sound.
PERCUSSION - With a name that means, "the hitting of one body against another," instruments in the percussion family are played by being struck, shaken, or scraped. In the orchestra, the percussion section provides a variety of rhythms, textures and tone colors. Percussion instruments are classified as tuned or untuned. Tuned instruments play specific pitches or notes, just like the woodwind, brass and string instruments. Untuned instruments produce a sound with an indefinite pitch, like the sound of a hand knocking on a door. The percussion instruments are an international family, with ancestors from the Middle East, Asia, Africa, the Americas and Europe representing musical styles from many different cultures.
KEYBOARD instruments are often classified as percussion instruments because they play a rhythmic role in some music. However, most keyboard instruments are not true members of the percussion family because their sound is not produced by the vibration of a membrane or solid material.