Whistle: Difference between revisions
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[[Image:Police whistles.jpg|right|250 px|Examples of police whistles]] | [[Image:Police whistles.jpg|right|250 px|Examples of police whistles]] | ||
The term '''whistle''' usually refers to a one-note [[woodwind]] instrument which produces [[sound]] from a stream of forced air. (For the sound produced with the mouth, see [[whistling]] and [[whistled language]].) | The term '''whistle''' usually refers to a one-note [[woodwind]] instrument which produces [[sound]] from a stream of forced air. (For the sound produced with the mouth, see [[whistling]] and [[whistled language]].) | ||
Many types exist, from small police whistles (also called [[pea whistles]]), to much larger steam whistles used on [[locomotive]]s and [[ship]]s. They are not usually considered 'musical' as such, but musical versions that work on the same principle exist, including any of several 2-[[octave]] musical instruments known as [[tin whistle]]s (sometimes known as pennywhistles or low whistles), [[Organ (music)|organ]] pipes and the [[recorder]]. | Many types exist, from small police whistles (also called [[pea whistles]]), to much larger steam whistles used on [[locomotive]]s and [[ship]]s. They are not usually considered 'musical' as such, but musical versions that work on the same principle exist, including any of several 2-[[octave]] musical instruments known as [[tin whistle]]s (sometimes known as pennywhistles or low whistles), [[Organ (music)|organ]] pipes and the [[recorder]]. | ||
The whistle works by causing the smooth flow of air to be split by a narrow blade, sometimes called a | The whistle works by causing the smooth flow of air to be split by a narrow blade, sometimes called a [[fipple]], creating a [[turbulence|turbulent]] [[vortex]] which causes the air to vibrate. By attaching a [[resonance|resonant]] chamber to the basic whistle, it may be tuned to a particular note and made louder. The length of the chamber typically defines the resonant [[frequency]]. A whistle may also contain a small light ball, usually called the ''[[pea]]'', which rattles around inside, creating a [[chaos|chaotic]] [[vibrato]] effect that intensifies the sound. | ||
A steam whistle works the same way, but using steam as a source of pressure: such whistles may produce extremely high sound intensities. | A steam whistle works the same way, but using steam as a source of pressure: such whistles may produce extremely high sound intensities. | ||
Sometimes, unintentional whistles can be set up. A common one is the opened [[sunroof]] of a [[Automobile|car]]: air passing over the top of the vehicle can, at certain speeds, strike the back edge of the sunroof, creating a very low frequency whistle which is resonated by the closed interior of the car. Since the sound frequency is [[infrasonic]], around 4 [[Hz]], the effect is very uncomfortable for occupants, who feel the vibration rather than hear it. Such low frequencies can induce [[nausea]], [[headache]], [[delirium|disorientation]] and [[dizziness]]. The effect can be prevented by opening a side window a few inches. | Sometimes, unintentional whistles can be set up. A common one is the opened [[sunroof]] of a [[Automobile|car]]: air passing over the top of the vehicle can, at certain speeds, strike the back edge of the sunroof, creating a very low frequency whistle which is resonated by the closed interior of the car. Since the sound frequency is [[infrasonic]], around 4 [[Hz]], the effect is very uncomfortable for occupants, who feel the vibration rather than hear it. Such low frequencies can induce [[nausea]], [[headache]], [[delirium|disorientation]] and [[dizziness]]. The effect can be prevented by opening a side window a few inches. | ||
==Industrial whistles== | |||
Industrial whistles are used for [[signal]]ling and [[time|timekeeping]] both on [[railroad]] and [[ship]]s, and in [[factory|factories]]. Most of these whistles were [[steam power]]ed and not standardized. Individual [[locomotive]]s could be identified by their whistles. At noontime in industrial areas up into the [[1950s]] whistles of every pitch could be heard, as each factory had a boiler and a whistle, if not full steam power. | |||
Railroads in particular used elaborate whistle codes for communication both within the [[train]] and with other trains. These methods are maintained today with motor-powered [[air horn]]s. | |||
Whistles are often used as warning devices or as safety devices serving to attract attention to the user. Some [[cyclist]]s use a whistle as a substitute for a [[bell]] or [[horn]]. It should be noted, however, that many jurisdictions require that the warning device be permanently attached to the [[bicycle]]. | Whistles are often used as warning devices or as safety devices serving to attract attention to the user. Some [[cyclist]]s use a whistle as a substitute for a [[bell]] or [[horn]]. It should be noted, however, that many jurisdictions require that the warning device be permanently attached to the [[bicycle]]. | ||
[[Category:Woodwind instruments]] | [[Category:Woodwind instruments]] | ||
[[ja:ホイッスル]] | [[ja:ホイッスル]] | ||
Revision as of 05:44, 15 November 2004
Whistle! is a manga by Daisuke Higuchi.
The term whistle usually refers to a one-note woodwind instrument which produces sound from a stream of forced air. (For the sound produced with the mouth, see whistling and whistled language.)
Many types exist, from small police whistles (also called pea whistles), to much larger steam whistles used on locomotives and ships. They are not usually considered 'musical' as such, but musical versions that work on the same principle exist, including any of several 2-octave musical instruments known as tin whistles (sometimes known as pennywhistles or low whistles), organ pipes and the recorder.
The whistle works by causing the smooth flow of air to be split by a narrow blade, sometimes called a fipple, creating a turbulent vortex which causes the air to vibrate. By attaching a resonant chamber to the basic whistle, it may be tuned to a particular note and made louder. The length of the chamber typically defines the resonant frequency. A whistle may also contain a small light ball, usually called the pea, which rattles around inside, creating a chaotic vibrato effect that intensifies the sound.
A steam whistle works the same way, but using steam as a source of pressure: such whistles may produce extremely high sound intensities.
Sometimes, unintentional whistles can be set up. A common one is the opened sunroof of a car: air passing over the top of the vehicle can, at certain speeds, strike the back edge of the sunroof, creating a very low frequency whistle which is resonated by the closed interior of the car. Since the sound frequency is infrasonic, around 4 Hz, the effect is very uncomfortable for occupants, who feel the vibration rather than hear it. Such low frequencies can induce nausea, headache, disorientation and dizziness. The effect can be prevented by opening a side window a few inches.
Industrial whistles
Industrial whistles are used for signalling and timekeeping both on railroad and ships, and in factories. Most of these whistles were steam powered and not standardized. Individual locomotives could be identified by their whistles. At noontime in industrial areas up into the 1950s whistles of every pitch could be heard, as each factory had a boiler and a whistle, if not full steam power.
Railroads in particular used elaborate whistle codes for communication both within the train and with other trains. These methods are maintained today with motor-powered air horns.
Whistles are often used as warning devices or as safety devices serving to attract attention to the user. Some cyclists use a whistle as a substitute for a bell or horn. It should be noted, however, that many jurisdictions require that the warning device be permanently attached to the bicycle.