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Piano/Rhythm
Reference material by Wikibooks contributors. This retains its source identity and is not 411 news reporting.
There are two essential pieces to music: rhythm and pitch. Pitch refers to how high or low a note is in tone, whereas rhythm refers to the arrangement of those tones. Since pitch can get fairly complicated, let us first discuss rhythm.
Beats
thumb|File:Middle C.mid
A beat in music is a "pulse." For instance, if you played one note on the piano, it might sound like this:
thumb|left|600px|File:Wolfgang Amadeus Mozart - sonata no. 16 in c major, k.545 'sonata facile' - i. allegro.ogg Sonata No. 16 (Mozart)
A beat can have any duration, even as long as a minute. Thus, to define duration, a composer includes a tempo like allegro at the top of the sheet music.
Types of Beats
thumb|200px|Parts of a Note
Fundamentally, all rhythms are a composition of the following beats:
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A quarter note is 1/4 of a whole note; tempos are assigned based on the quarter note's duration, since it is 1 beat long.
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A half note is played for half the duration of a whole note.
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A whole note is 4 beats.
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An eighth note is 1/2 of a quarter note. It takes 8 of these to fill a whole note.
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A sixteenth note is 1/4 of a quarter note. It takes 16 of these to fill a whole note.
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A thirty-second note is 1/8 of a quarter note. It takes 32 of these to fill a whole note. Note durations keep halving with each new "flag" added.
Dotted Notes
thumb|200px|Dotted Half Notes
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When a note is dotted, it adds 1/2 of its duration to its current duration.
A dotted quarter note lasts for 1.5 (1 + 1/2) beats, equivalent to a quarter note tied to an eighth note.
Time Signatures
thumb|4/4, Common Time, 2/2, Half Time, 2/4, 3/4, and 6/8
Time signatures are the number of beats per measure.
For example,
2/4 ("half time") = 2 beats per measure
3/4 = 3 beats per measure
4/4 ("common time") = 4 beats per measure
Same applies for anything over 8 except there would be twice as many notes involved