I’m now going to talk a little about some of the technical aspects of music. If you don’t understand everything at first, don’t worry. Everything will become clearer as we move along.
There are twelve notes in music; they are (going up a half-step at a time) A, A#, B, C, C#, D, D#, E, F, F#, G, and G# (# = sharp). After that G# comes A again, only one octave higher than the A we started on. There is a whole step (two half steps) from one note to another except from B to C and E to F, which are half steps (that is why there’s no B# and E#). This business of half steps and whole steps can be illustrated best on a piano keyboard: from one key to another (regardless of color) is a half step, and two half steps make a whole step. Now, remember the major scale? You probably learned it in school, when your teacher had you sing "do, re, mi, fa, so, la, ti, do." Every note has a major scale, and we say that the major scale is in the "key" of the note on which it starts. So, for example, a major scale that begins on C is a C major scale. A major scale can be defined as follows: starting from the first note, "do" (which determines the key), go up a whole step to "re"; from "re" go up a whole step to "mi"; from "mi" go up a half step to "fa"; from "fa" go up a whole step to "so"; from "so" go up a whole step to "la"; from "la" go up a whole step to "ti"; and from "ti" go up a half step to "do." So that’s whole step, whole step, half step, whole step, whole step, whole step, half step. Thus the C major scale (which has no sharps or flats) is C, D, E, F, G, A, B, C. To play this scale on a piano, begin on C, and play the white keys until you reach C again. We can also assign the notes in a major scale numbers: 1, 2, 3, 4, 5, 6, 7, 1. For example, in C major, C = 1, D = 2, E = 3, F = 4, G = 5, A = 6, B = 7, and C = 1 (or 8, because it’s an octave higher than the C we started on). Now we can say that in any major scale there is a half step from 3 to 4 and from 7 to 1; except for those two instances, the interval between notes in the major scale is a whole step.