What is Tuning fork?
[[File:Tuning fork on resonator.jpg|thumb|right|250px|Tuning fork on resonance box, by Max Kohl, Chemnitz, Germany]] A '''tuning fork''' is a sound [[resonator]] which is a two-pronged [[fork]]. The prongs, called [[tine]]s, are made from a U-shaped bar of metal (usually steel). This bar of metal can move freely. It [[resonance|resonates]] at a specific constant [[pitch (music)|pitch]] when set [[vibrate|vibrating]] by striking it against an object. It sounds a pure musical tone after waiting a moment to allow some high [[overtone]] sounds to die out. The pitch depends on the length of the two prongs. Its main use is as a standard of pitch to tune other [[musical instrument]]s, and in some tests of hearing. ==Description== [[File:TuningFork659Hz.jpg|thumb|Tuning fork by John Walker stamped with note (E) and frequency in hertz (659)]] The tuning fork was invented in 1711 by British musician [[John Shore]]. He was the Sergeant Trumpeter to the court, who had musical parts written for him by the composers [[George Frideric Handel]] and [[Henry Purcell]]. The fork shape produces a very [[pure tone]]. Most of the vibrational energy is at the [[fundamental frequency]], with very few [[overtone]]s ([[harmonic]]s). This is not the case with other resonators. The reason for this is that the frequency of the first overtone is about 5<sup>2</sup>/2<sup>2</sup> = 25/4 = 6¼ times the fundamental (about 2½ octaves above it).<ref>{{cite book | last = Tyndall | first = John | title = Sound | publisher = D. Appleton & Co. | year = 1915 | location = New York | page = 156 | url = https://books.google.com/books?id=hCgZAAAAYAAJ&pg=PA156 }}</ref> By comparison, the first overtone of a vibrating string is only one octave above the fundamental. So when the fork is struck, little of the energy goes into the overtone modes; they also die out correspondingly faster, leaving the fundamental. It is easier to tune other instruments with this pure tone, when listening to compare with the tone of each other instrument. Another reason for u