Object, Instrument, Technology

See also Tuning fork

Picture: Max Planck Institute for the History of Science

Image
“Tuning Fork Collection Ii, Detail 1”. n.d. Berlin.
Object, Instrument, Technology

Picture: Max Planck Institute for the History of Science

Object, Instrument, Technology

Wooden sticks, when dropped on the floor, sound a variety of tones. While the bars of a xylophone are varied in tone by changing their length, these “tone bars” are all of the same length and width, but have different thicknesses and different densities and elastic properties.

Object, Instrument, Technology

The Case Collection of Physics Instruments (CCPI) has several dozen forks mounted on resonance boxes (see Fig. 1).

Object, Instrument, Technology

A tonometer consists of a series of steel cylinders that resonate at specific frequencies upon being struck with a metal hammer. They are used as standards for high frequencies, in the same manner as tuning forks. The transverse vibrational frequencies (i.e. fundamental and harmonics) of a given cylinder depend on the length, elastic modulus, and linear density of the metal.

Object, Instrument, Technology

William Stern invented the tone variator in 1897 to study human sensitivity to changes in pitch, going beyond the traditional psychological research of studying the sensitivity to differences in discrete tones. The instrument consists of an adjustable brass resonator (see Helmholtz resonator for more information), which is supplied with a constant flow of air across an opening at the top.

Image
“Tuning Fork Collection Ii, Detail 6”. n.d. Berlin.
Object, Instrument, Technology

See also Tuning fork

Picture: Max Planck Institute for the History of Science

Object, Instrument, Technology

Helmholtz described in his 1862 [sic] book, On the Sensations of Tone, an apparatus able to pick out specific frequencies from a sound. The Helmholtz resonator, as it is now called, consists of a rigid container of a known volume, nearly spherical in shape, with a small neck and hole in one end and a larger hole in the other end to admit the sound.