THE Piano

Piano is the general name given to a musical instrument classified as a keyboard, percussion, or string instrument, depending on the system of classification used.
The piano produces sound by striking steel strings with felt hammers that immediately rebound allowing the string to continue vibrating at its resonant frequency. These vibrations are transmitted through the bridges to the soundboard, which amplifies them.
The piano is widely used in western music for solo performance, chamber music, and accompaniment. It is also very popular as an aid to composing and rehearsal. Although not portable and often expensive, the piano's versatility and ubiquity has made it among the most familiar of musical instruments. The word piano is a shortened form of the word pianoforte, which is seldom used except in formal language and derived from the original Italian name for the instrument, gravicèmbalo col piano e forte (literally harpsichord with soft and loud). This refers to the ability of the piano to produce notes at different dynamic levels depending on the speed with which a key is depressed.



Keyboard
Almost every modern piano has 88 keys (seven octaves plus a minor third, from A0 to C8). Many older pianos only have 85 keys (seven octaves from A0 to A7), while some manufacturers extend the range further in one or both directions. The most notable example of an extended range can be found on Bösendorfer pianos, one model which extends the normal range downwards to F0, with one other model going as far as a bottom C0, making a full eight octave range. Sometimes, these extra keys are hidden under a small hinged lid, which can be flipped down to cover the keys and avoid visual disorientation in a pianist unfamiliar with the extended keyboard; on others, the colours of the extra white keys are reversed (black instead of white). The extra keys are added primarily for increased resonance from the associated strings; that is, they vibrate sympathetically with other strings whenever the damper pedal is depressed and thus give a fuller tone. Only a very small number of works composed for piano actually use these notes. More recently, the Stuart and Sons company has also manufactured extended-range pianos. On their instruments, the range is extended both down the bass to F0 and up the treble to F8 for a full eight octaves. The extra keys are the same as the other keys in appearance.