Note pitches can be modified by using accidentals:

Accidental	Name	Effect
	sharp	Raises the note 1 half step
	flat	Lowers the note 1 half step
	double sharp	Raises the note 2 half steps or 1 whole step
	double flat	Lowers the note 2 half steps or 1 whole step
	natural	Cancels any previous accidental

In music notation, an accidental affects every note of the same name, in the same voice and in the same octave within a bar. In the following example, the last G note is sharp (we would have to add a natural sign if we wanted it to be natural):

For more information on accidentals and their relationship to the piano, see whole and half steps.

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