If we start on G and write a major scale, we write a note on every line and in every space between the two G notes, as shown in Figure 20:
Next, check the intervals. All intervals must be correct, including the semitone between the 3rd and 4th degrees (B and C), until we finish checking the last two notes: F and G. Now we see that the interval between the 6th and 7th degrees (E and F) is a semitone, while the interval between the 7th and 8th degrees (F and G) is a whole tone. This is wrong: the position of the semitone is incorrect. The interval between the 6th and 7th degrees should be a whole tone, and the interval between the 7th and 8th degrees should be a semitone. We can correct this with a simple step: we just need to raise the 7th degree by a semitone — in other words, change F to F #, as shown in Figure 21:
Note that F # cannot be written as Gb , because then the fifth line would be missing a note, and the scale would look incomplete.
Apart from C major, every other major scale contains at least one black-key note. If we try to write a major scale starting on D, we need two black-key notes: to maintain the correct order of semitones and whole tones, we must not only raise the 7th degree, but also raise the 3rd degree:
Sometimes we must lower one or more notes in order to maintain the correct order of a major scale. In Grade 1, we have only one such example, which is F major. The 4th degree of F major, B, must be changed to B b :
