tuning fork

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tuning fork,

steel instrument in the shape of a U with a short handle. When struck it produces an almost pure tone, retaining its pitch over a long period of time; thus it is a valuable aid in tuning musical instruments. It was invented in 1711 by John Shore, who jokingly called it a pitchfork.
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Tuning fork

A steel instrument consisting of two prongs and a handle which, when struck, emits a tone of fixed pitch. Because of their simple mechanical structure, purity of tone, and constant frequency, tuning forks are widely used as standards of frequency in musical acoustics. In its electrically driven form, a tuning fork serves to control electric circuits by producing frequency standards of high accuracy and stability. A tuning fork is essentially a transverse vibrator (see illustration). See Vibration

A tuning fork vibrating at its fundamental frequencyenlarge picture
A tuning fork vibrating at its fundamental frequency
McGraw-Hill Concise Encyclopedia of Physics. © 2002 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Tuning Fork


a source of sound, consisting of a metal rod that is bent and fixed in the center. The ends of the rod can vibrate freely. During the tuning of musical instruments, the tuning fork serves as the standard pitch of a tone; it is also used to give the pitch in singing. Forks that produce the tone A’ (A of the first octave) are usually used. Singers and choral conductors also use forks producing the tone C”. There are chromatic tuning forks, with prongs that have movable little weights. Depending on the position of these weights, the prongs vibrate at different frequencies.

The tuning fork was invented by the English musician J. Shore in 1711. At that time the standard frequency of vibrations for the tone A’ was 419.9 hertz (Hz). In the late 18th century the composer and conductor G. Sarti, who was working in St. Petersburg, introduced the “St. Petersburg tuning fork,” with an A’ = 436 Hz. In 1858 the Paris Academy of Sciences proposed a standard pitch tuning fork with A’ = 435 Hz. In 1885 at an international conference in Vienna this frequency was adopted as the international standard pitch for the tone A’; the frequency was called the standard musical pitch. Since Jan. 1, 1936, an all-Union standard pitch of A’ = 440 Hz has been in effect in the USSR.


MuzykaVnaia akustika. Edited by N. A. Garbuzov. Moscow-Leningrad, 1940.
The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.

tuning fork

[′tün·iŋ ‚fȯrk]
A U-shaped bar for hard steel, fused quartz, or other elastic material that vibrates at a definite natural frequency when struck or when set in motion by electromagnetic means; used as a frequency standard.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

tuning fork

a two-pronged metal fork that when struck produces a pure note of constant specified pitch. It is used to tune musical instruments and in acoustics
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
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The experimental results suggest that tuning fork sensor with long long tip would be a promising set-up for the measurements and imaging in liquid.
The torquer exerts the drive signal on the drive electrodes to stimulate the tuning fork resonator in the harmonic frequency.
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In the experiment, Jin measured the temperature change in both arms of the tuning fork and subtracted one from the other, both with and without a 7-tesla magnetic field turned on.
The sound of the tuning fork cannot be heard more than 100cms distance from the ear, and the patients were asked to look at the ceiling to make visual bias impossible.
Distance control for a near-field scanning microwave microscope in liquid using a quartz tuning fork. Appl.
In patients with a DNS score of zero, 91.1 per cent had a VPT score of < 25 mV and monofilament sensation, tuning fork sensation and ankle reflex were preserved in 895 (85.7%), 909 (87.1%) and 765 (73.3%) patients respectively.
Hold the tuning fork upside down between your thumb and index finger, with the prongs pointing downward.
No more than a lightbulb whose long electrical cord has been sliced open to allow the copper wiring to be soldered to the ends of a tuning fork, the sculpture prompts koanlike questions such as, What is the sound of light?
ATLANTA -- The clanging tuning fork test is far more accurate and sensitive than is the 10-g monofilament in screening diabetes patients for peripheral neuropathy, results from two studies suggest.
There are four primary tools that are used in DTR radar calibration methods: a tuning fork, a speed simulator based on amplitude modulation (AM) of the reflected radar signal, the vehicle's speedometer, and a fifth-wheel.