Definition of tone, semitone, sharp and flat
In western music, there are 12 notes: C, C#, D, D#, E, F, F#, G, G#, A, A# e B. The symbol “#” means sharp. From these 12 notes, 7 of them receive a specific name (do, re, mi, fa, sol, la, si) and the other notes are identified for a sharp (#) or flat (b) of these notes, also called accident. A sharp, by definition is the smaller distance between two notes in western music, as well as the flat. The difference in nomenclature (flat and sharp) serves only to indicate if we are referring to a note above or below. For example: Re flat is the same as Do sharp. Read the next section “tones and semitones” to complement this concept. Here below there are some representations and their equivalences, to make the understanding easier:
Re # # = Mi
Mi b b = Re
Mi # = Fa
Fa b = Mi
In fact, we don’t use the way of writing ## or bb because is easier to say, for example, C instead of D##. It doesn’t make sense to use this second representation; we showed here only for understanding meanings. In the same way, it’s not common to use the nomenclature E#, nor B#, for being F and C, respectively.
If you are curious about the mathematics that exists among the 12 notes in western music and what makes a note different from another one in our brain perception, read the Mathematics in Music article.
Observation: in piano, the white keys have the notes with specific names (C, D, E, F, G, A, B) and the black ones have the notes with the accidents (C#, D#, F#, G#, A#).
What are tones and semitones?
A tone is a distance of two sharps (or two flats). A semitone is the distance of one sharp (or one flat). For example, the distance between C and D is a tone, because between C and D there is a distance of two flats (from C to C# and from C# to D). Simple, don’t you think? To make it clearer, nothing better than some exercises:
What is the distance between the notes G and B? Let’s see how many flats (semitones) there are between G and B:
So, there are 4 sharps of distance, which means 2 tones. Now that you know how to say the distance between notes, try to find the distance between D and F. And then check it below.
Then, the distance is a tone and a half. Observation: A tone and a half = one tone + one semitone. In the instruments: classic guitar, electric guitar, bass, ukulele, among others, each fret corresponds to a semitone.