A guitar string has a number of frequencies at which it will naturally vibrate. These natural frequencies are known as harmonics. The frequency at which an object vibrates at depends upon the tension of the string, the linear density of the string and the length of the string. Each of these natural frequencies or harmonics is associated with a standing wave pattern. Also, the length of strong required to produce a natural frequency could be predicted by using the wave equation (v= frquency x wavelength).