# Major Scale (Lesson 9)

A scale is divided into two halves, called tetrachords. The scale degrees are determined by a formula outlining the intervals or steps. This formula (for every Major and Relative or Natural Minor) is as follows: tone, tone, semitone, {tone}, tone, tone, semitone or whole (step), whole, half, {whole}, whole, whole, half. Since these scales are divided into two halves or tetrachords, each scale contains two distinct scales. (As you will notice above, one tone or whole step separates the second half of the scale).

For instance, in both a C Major scale and the key of C Major (C, D, E, F, G, A, B), the interval formula yields not only a C Major scale, but a G Major scale as well. The G Major (or perfect fifth of the C Major scale) is found beginning on the second half or upper tetrachordalso known as the 5th degree. In order to form the G Major scale in its entirety, the interval formula of tone, tone, semitone, {tone}, tone, tone, semitone must be applied. From this point, one can see that the G Major incurs a raising or sharpening of the seventh note or degree – from F to F#. Therefore, a G Major scale is in accord with the G Major key signature (G, A, B, C, D, E, F#).

As one can easily deduce, the procedure of following the tone, tone, semitone, {tone}, tone, tone, semitone pattern from the upper tetrachord or 5th degree will yield all of the twelve major keys and scales around the Circle of Fifths.

Continue to Lesson 10: Minor Scales