Explain the Resonance of Sound in Strings

Strings on musical instruments, like harps, are held still at both ends, that is why the standing waves have nodes at every end of the string. The lowest natural frequency of the string's sound is known as the fundamental frequency. The wavelength of the primary frequency is equal to two times the length of the string.

While playing guitars and violins, the length of the vibrating part of the string can be altered with finger placement. Several frequencies of sound - that is, several notes - can be acquired as you change the length of the vibrating part of the string.