What is the purpose of a sharp and flat note?

Answer 1

The Western musical system has 12 individual semitones which divide the octave (an octave being the point at which the musical system repeats itself). However, the Western musical system only uses seven letter names to represent notes (A, B, C, D, E, F, G). The remainder of the 5 notes are given names which identify their relationship between the note and the closest named note.

On the piano keyboard, the "named" notes are the white notes. The black notes take their names from the closest white note.

The purpose of Sharps/flats is to raise/lower a note by a half-step.

The word "sharp" indicates a note which is half-step higher (to the right). C-sharp (also, C#) is the black note to the right of the note named "C". D# is the black note to the right of the note named "D".

The word "flat" indicates a note which is half-step lower (to the left). E-flat (also, Eb) is the black note to the left of the note named "E". Db is the black note to the left of the note named "D".

This naming system creates two strange issues.

First, each black note takes on two different names. The black note to the right of C is also to the left of D. This means that this note is known as both C# and Db. Musicians say that C# is the ENHARMONIC EQUIVALENT to Db, and understand that both names refer to the same location on the keyboard.

Second, because not every white note has a black note beside it, certain white notes can also be known by "sharp" or "flat" terminology. For example, there is no black note in between B and C, and no black note in between E and F.

This means that C is to the right of B, and is therefore also B#. B is to the left of C, and is therefore also Cb. By the same logic, F is E# and E is Fb.

Answer 2

Double sharps (and double flats), sharpen or flatten any note by a whole step, so D double flat, which is "D-flat" flat, is the enharmonic for C natural.

Answer 3

It's called an "accidental."

Answer 4

no