• String instruments share a distinct shape, a wooden body and extended fretboard.string musical instruments illustration image by Slobodan Djajic from Fotolia.com
  
  Some musical instruments have pedals and keys, like the piano. Others require the user to blow into it to create a sound, like the clarinet or flute. Some instruments contain strings which produce a variety of sounds, when plucked or strummed by the human hand, or vibrated with a bow.
  
  

Acoustic Guitar

• The round hole in the acoustic guitar body.acoustic guitar 1 image by Trevor Allen from Fotolia.com
  
  Guitars can be acoustic or electric. Acoustic guitars consist of hollow bodies that do not rely on an electrical charge to emit a sound. The body contains a round hole behind six strings, which are either steel or nylon. The hole ranges from 3 1/4 to 3 1/2 inches in diameter, depending on the size of the instrument, and adds strength to the guitar's sound. The fret board reaches out of the hollow body's side, comprised of frets arranged one semitone apart. The guitar's body is made of either spruce or cedar. Spruce usually indicates folk acoustics, while cedar indicates classical acoustics.
  
  

Electric Guitar

• Electric guitars require electromagnetic energy to create sound.electric guitar image by Blue Moon from Fotolia.com
  
  While the acoustic guitar depends on its hollow body to create resounding music, the electric guitar requires an electromagnetic pickups and amplifiers to create sound. Pickups can be treble or bass. Treble pickups occur at the bridge, while bass pickups occur at the guitar's center and near its neck.
  
  

Violin

• Violins are associated with classical music and string quartets.violin image by Mateusz Papiernik from Fotolia.com
  
  Mainly associated with classical music, the violin is the most commonly-used string instrument. With four strings, the violin has the highest sound of all string instruments. The strings stretch across the instrument's bridge which restricts the user to play a maximum of two strings, and three or four chords at a time. Violins average 23 1/2 inches in length, while strings are an average 12 3/4 inches from the bridge to the end of the fingerboard. Users must always hold the violin on the left side of their body with the right hand gliding the bow across the strings. This causes a vibration in the strings which results in the violin's versatile sound and range, from dark and moody to harmonic and mellow.
  
  

Cello

• The cello's large size requires the celloist to remain seated while playing.Playing cello image by TekinT from Fotolia.com
  
  The 'cello, short for violincello, can play the melody or bass line in the orchestra. The 'cello's body averages 30 inches long, requiring the cellist to play the instrument sitting down. While the top plate consists of either spruce or pine, the sides and back of the instrument are maple, with an ebony fingerboard and indented piece to hold the strings in position. The cellist plays one string at a time and produces a deeply resonating sound, vibrating the strings with his bow.
  
  

Double Bass

• The double bass or contrabass.d??tail d"une contrebasse image by S??bastien Maurer from Fotolia.com
  
  Also known as the contrabass, the double bass has sloped shoulders and high ribs that create a box-like shape, and give the instrument its resonant sound. The double bass averages from 70 to 78 inches long. The bow is shorter and thicker than the 'cello bow, and made of coarser horsehair. The maple instrument also has an bony fretboard extending from the body.