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Pedal

The word pedal comes from the Latin (Pes, Pedis) and relates to the foot.

A pedal is a lever activated by one's foot. Examples include:

  • An automobile has usually three pedals, from left to right:
    • operated by the left foot:
      • clutch pedal (except in the case of automatic transmission)
    • operated by the right foot:
      • brake pedal, which is usually wide and elevated well above the car floor
      • gas pedal (accelerator): controls air supply to the automobile's engine. It is usually narrow and close to the car floor allowing the driver's heel to rest on the car floor.
  • Bicycle pedal: on a bicycle, each of two platforms at the end of the crankarms, connected such that while the crank arms rotate, the pedals can stay parallel to the shoe soles; this human powered rotation provides the propulsion, usually through a bicycle chain that makes the back wheel turn. In the case of a back pedalling brake, they are also used for applying the brake in the back wheel, again through the chain.
  • A pedalo is a small boat, usually used for recreational purposes, powered by pedals.
  • Most pianos have two or three piano pedals (from left to right):
    • A soft pedal which causes the hammer to hit only two strings of a note instead of three. This creates a "softer" sound.
    • A sostenuto pedal (usually the one missing if the piano has only two pedals) works similar to the damper pedal except only the notes being played when the pedal is depressed are sustained.
    • A damper pedal (sometimes called the sustain pedal) which causes notes to sustain after the key for that note has been released.
  • Pipe and electronic organs have a variety of pedals, some of which are:
    • The pedalboard, which contains approximately one dozen to three dozen pedals that resemble the keyboards (or "manuals"); when one of these pedals is depressed, it causes a note (or group of notes) to sound.
    • One or more expression pedals, which effectively control the volume either of the music overall or of discrete divisions; as the organist increases pressure, the power of her music increases.
    • A crescendo pedal, with which the organist progressively adds stops as she presses down more and more firmly.
    • An effects pedal, which, on electronic organs, may be programmed to alter pitch or perform other functions.
  • Electric pianos and synthesizers can also connect to pedals. Some electric pianos, like the Fender Rhodes, uses a mechanical pedal for sustain. Synthesizers use an electronic pedal, which can function as a sustain pedal or be programmed to perform other functions.
  • Effects pedal used commonly for electric guitars
  • Tap pedal: this is a small electronic pedal, similar or identical to the ones used with synthesizers, but is connected to audio effects equipment, a music sequencer, or drum machine. The purpose is to tap the pedal in time with the music, which allows the sequencer or drum machine to stay "in-sync". When connected to audio effects, it can be used to "tap in" the length for a digital delay or flange, or to cause an effect loop to be bypassed.
  • Pedal tone: a nonchord tone, usually the tonic or dominant held for an extended period of time.
  • not to be confused with a paddle.
  • Pedal pumping is the sexual fetish of seeing women use pedals, usualy in cars.

Geometry: see also pedal triangle, pedal curve.

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Geometry: see also pedal triangle, pedal curve. In astrology Polaris is one of the Behenian fixed stars and has the symbol . Examples include:. However, the bright Southern Cross (Crux) points towards the south celestial pole. A pedal is a lever activated by one's foot. The star visible to the naked eye that is closest to the south celestial pole is the dim Sigma Octantis, sometimes called Polaris Australis. The word pedal comes from the Latin (Pes, Pedis) and relates to the foot. There is no real southern pole star.

Pedal pumping is the sexual fetish of seeing women use pedals, usualy in cars. The astronomer Edward Guinan considers this to be a remarkable rate of change and is on record as saying that "If they are real, these changes are 100 times larger than [those] predicted by current theories of stellar evolution". not to be confused with a paddle. Recent research reported in Science suggests that Polaris is 2.5 times brighter today than when Ptolemy observed it. Pedal tone: a nonchord tone, usually the tonic or dominant held for an extended period of time. The star is also about 15% brighter (on average) than it was in 1900; the period has also lengthened by about 8 seconds each year since then. When connected to audio effects, it can be used to "tap in" the length for a digital delay or flange, or to cause an effect loop to be bypassed. As of 2005, the variations are about 2% from peak to trough.

The purpose is to tap the pedal in time with the music, which allows the sequencer or drum machine to stay "in-sync". Around 1900, the star varied between being 8% brighter than its average luminosity and 8% dimmer (0.15 magnitudes in total) with a 3.97 day period. Tap pedal: this is a small electronic pedal, similar or identical to the ones used with synthesizers, but is connected to audio effects equipment, a music sequencer, or drum machine. The main star is a Population II cepheid variable, the pulsations of which cause it to cycle steadily. Effects pedal used commonly for electric guitars. It is an F7 supergiant (Ib) or bright giant (II), with two smaller companions: an F3 V main sequence star about 2700 AU away and a close companion about 20 AU distant. Synthesizers use an electronic pedal, which can function as a sustain pedal or be programmed to perform other functions. Polaris is 431 light years (132 parsecs) from Earth, according to measurements made by the Hipparcos satellite.

Some electric pianos, like the Fender Rhodes, uses a mechanical pedal for sustain. See List of brightest stars. Electric pianos and synthesizers can also connect to pedals. The brightest star in the sky (besides the Sun) is Sirius. An effects pedal, which, on electronic organs, may be programmed to alter pitch or perform other functions. Although Polaris is a relatively bright star and is conspicuous since no other stars of similar brightness are close to it, it is nowhere near the brightest; it is actually the 46th brightest star in the night sky. A crescendo pedal, with which the organist progressively adds stops as she presses down more and more firmly. Polaris's fame as the North Star has given rise to a persistent misconception that it is the brightest star in the sky.

One or more expression pedals, which effectively control the volume either of the music overall or of discrete divisions; as the organist increases pressure, the power of her music increases. Polaris is not normally visible from the Southern Hemisphere. The pedalboard, which contains approximately one dozen to three dozen pedals that resemble the keyboards (or "manuals"); when one of these pedals is depressed, it causes a note (or group of notes) to sound. One can also follow the central point of the W shape of Cassiopeia. Pipe and electronic organs have a variety of pedals, some of which are:

    . In the Northern Hemisphere, it is easy to find Polaris by following the line traced from Merak to Dubhe (β and α Ursae Majoris, also known as the Pointers), the two stars at the end of the bowl of the Big Dipper. A damper pedal (sometimes called the sustain pedal) which causes notes to sustain after the key for that note has been released. Polaris is due to become an even more accurate pole star in the near future — the distance between Polaris and the pole will reach a minimum (of just under 1/2 degree) in 2100.

    A sostenuto pedal (usually the one missing if the piano has only two pedals) works similar to the damper pedal except only the notes being played when the pedal is depressed are sustained. Other stars have been the pole star in the past and will be again in the future, including Thuban and Vega. This creates a "softer" sound. This is due to precession of the equinox over thousands of years. A soft pedal which causes the hammer to hit only two strings of a note instead of three. Although Shakespeare wrote "I am as constant as the northern star", Polaris will not always be the pole star. Most pianos have two or three piano pedals (from left to right):

      . Only twice during every sidereal day does Polaris accurately define the true north azimuth; the rest of the time it is only an approximation and must be corrected using tables.

      A pedalo is a small boat, usually used for recreational purposes, powered by pedals. At present, Polaris is slightly under 1° away from the pole of rotation (about twice the apparent diameter of the Moon) and hence revolves around the pole in a small circle almost 2° in diameter. In the case of a back pedalling brake, they are also used for applying the brake in the back wheel, again through the chain. The antiquity of the use of this star is attested to by the fact that it is found represented on the earliest known Assyrian tablets. Bicycle pedal: on a bicycle, each of two platforms at the end of the crankarms, connected such that while the crank arms rotate, the pedals can stay parallel to the shoe soles; this human powered rotation provides the propulsion, usually through a bicycle chain that makes the back wheel turn. Therefore, it makes an excellent fixed point from which to draw measurements for celestial navigation. It is usually narrow and close to the car floor allowing the driver's heel to rest on the car floor. Because it lies nearly in a direct line with the axis of the Earth's rotation "above" the North Pole—the north celestial pole—Polaris is apparently motionless from the Earth, and all the stars of the Northern sky appear to rotate around it.

      gas pedal (accelerator): controls air supply to the automobile's engine. Other names include the "North Star", the "Lode Star", or sometimes "Polaris Borealis". brake pedal, which is usually wide and elevated well above the car floor. "Polaris" comes from Stella Polaris, the Latin form of its common name "Pole Star." The Greek name Cynosura (Κυνόσουρα) means "tail of the dog" and is the source of the English word cynosure. operated by the right foot:

        . The nearer dwarf star is in an orbit of only 20 AU (3 billion km) from Polaris A, explaining why its light is swamped by its close and much brighter companion. clutch pedal (except in the case of automatic transmission). In January 2006, NASA released images from the Hubble telescope, directly showing all three members of the Polaris trinary system.

        operated by the left foot:

          . In 1929, it was discovered by examining the spectrum of Polaris A that it had another very close dwarf companion (variously α UMi P, α UMi a or α UMi Ab). An automobile has usually three pedals, from left to right:
            . Polaris B can be seen with even a modest telescope and was first noticed by William Herschel in 1780. Polaris is a trinary system, consisting of a large yellow Cepheid variable (α UMi A), distantly (about 2700 AU or 380 billion km) orbited by a bright yellow dwarf (α UMi B). Much more rarely, it is called Cynosura.

            It is also very close to the north celestial pole, making it the current north pole star. Polaris (α UMi / α Ursae Minoris / Alpha Ursae Minoris) is the brightest star in the constellation Ursa Minor.