Using the Major Scale: Mapping Out Intervals

Now that we are familiar with the major scale pattern and fingering, we can start to apply basic music principals to expand our understanding of chord structure and harmony.

All chords are built by stacking intervals on top of each other. In its simplest form, we use three intervals to give us the primary chords of a given key. These are known as triads and use the root, third, and fifth intervals to give the chord its individual sound. Each interval performs a specific task within the chord, and it is the way that they interact with each other that defines the nature of the chord: 

• The Root gives us the frame of reference from which the other notes are compared to and defines the range or pitch of the chord.
• The Third gives us the tonality of the chord and tells us whether it is minor or major.
• The Fifth gives the chord strength and reinforces the root note.

All the other intervals alter the sound of the chord when they are introduced, and it is therefore important to know how to locate them so that we may use them to our advantage, either in composing or improvising. You will have no doubt seen chords such as G7#5 or G13b5. If we are called upon to play a melodic line over chords such as these, we must be able to locate the chord tones and use them if the line is to make some sort of sense. Many guitar books will teach you the individual scales of each chord, but that is a vast amount of information to take in and quite unnecessary if you know the major scale pattern and how to apply it.

If you assign each note of the major scale pattern a number from 1 to 15, starting with the root as 1, you will immediately see the location of every interval in the key. In practical terms, we only use those up to the 13th, so ignore 14 and 15. As the pattern we are using is one of a major scale, all the intervals your fingers play will be "major" or "perfect".

Note that the 10th note is the Maj3rd interval one Octave higher, the 12th note is the perf5th interval one Octave higher, the 14th note is the maj7th one octave higher and the 15th note is the root note Two octaves higher.