Intervals – (Part 2 of 4)
An interval from G to B is a third because it contains three letter names: G, A, B. From G up to E is a sixth because it includes six letter names: G, A, B, C, D, E.
The interval from G up to B is a third. From G# to B is a third also. From G# to Bb is
once again a third. But these three thirds don’t sound the same because they are different-sized thirds.
G to B includes two whole steps: G to A, and A to B. And we know they’re whole steps because there is a note between each one. These two whole steps together make a major third.
G to Bb includes one whole step and one half-step: G to A, and A to Bb. A whole step plus a half-step equals a minor third.
Or, G# up to B also includes one whole step (G# to A#) and one half-step (A# to B). And we know that a whole step plus a half-step equals a minor third.
From G# to A is a half-step and from A to B is a whole step. In this case, even though the half-step in on the bottom and the whole step is on the top, it’s still adds up to a minor third.
A perfect 4th is one half-step larger than a major third. For example, G up to C, A up to D, Ab up to Db are all perfect 4ths.