Stringed instruments are instruments that create sound through resonating strings. When a string is plucked a wave is sent through it and sound resonates off the string dependent on the length and tension. The string family is very large and encompasses instruments ranging from the banjo to the violin to the string bass. The piano however, is not considered a string instrument despite how it is played this way. The large amount of stringed instruments are highlighted in the picture below.
A stringed instrument is played in one of three ways: plucking bowing or striking. The plucking technique is exactly what it sounds like. A player will pull and string and move it from its original position so that it tension will increase and will return to its original position producing a sound as a vibrates back and fourth. The bowing technique is very similar; the player will use a bow to utilize the slip-stick technique (Shown below) in which the string will vibrate at a sustained pitch and frequency dependent on the length of the string. Instruments like the Violin, Viola and Cello are instruments that are usually played with a bow however other techniques to vibrate the string can be used for a unique sound. The final technique that string players use the called the striking technique. It utilizes a small hit onto the string that will cause it to vibrate. The object used to hit may be something like a mallet or even the players hands. This allows the string to vibrate again differently to create a different sound.
Pitch of the string can be adjusted by length. A longer string will result in a lower pitch while a shorter one will result in a higher pitch. The frequency is therefore inversely proportional to the wavelength: f = 1/l. Therefore a string that is half as long will produce a sound that is one octave higher than the original pitch. The pitch of the string is also effected by the tension of the string. This means that if a string is more tense, the produced sound will be lower and if the string is more tense the produced sound will be higher. This is why players tune their instruments using the nobs at the top to adjust the tension.