Meet the Instruments--Strings

The string instruments are made of wood. They have four strings made of sheep gut, nylon, or wire. String instruments are tuned by turning pegs at the top. Sound is produced when the strings are stoked by bows made of horsehair, or when they are plucked by the player's fingers. To change notes, a player must press on the strings to change the string's length. 

Here are some examples of string instruments:
 
Violin  The violin is the smallest of the string instruments.  It's pitch is higher than other strings.  It has a warm, singing sound.  It is held under the player's chin.
 
Viola  The viola is slightly larger than the violin.  It has thicker strings and a lower, deeper pitch.  It is held under the player's chin.
 
Cello  The cello has rich, mellow tones that are thought to be closest to the sound of the human voice.  It is so large that the player needs to sit with the instrument tucked between her knees.
 
Bass  The bass has deep and powerful tones.  The player must stand or sit on a stool to play this tall instrument.  It is also called the double bass.