Learning Objectives

Examine the quality of the intervals in the major scale.
Learn how to use the major scale method of interval identification.

Intervals XI: Intervals in the Major Scale

Intervals in the Major Scale

Before we conclude this unit on intervals, it will be useful to examine the quality of the intervals that occur in a major scale. When you calculate all of the types of intervals that occur above the tonic of a major scale, you will see that all of the intervals are either major or perfect. Click on "Show Me" in the example below (using the F major scale) to see this illustrated. You can also explore by clicking on "Perfect," "Major," or any of the interval buttons.

Quality of the Intervals of the Major Scale

Quality of the intervals in a major scale

We can express these findings as a rule:

Rule

Measured from the tonic note of a major scale:
The intervals of the unison, fourth, fifth, and octave are always perfect.
The intervals of the second, third, sixth, and seventh are always major.

The prevalence of major intervals in the major scale is what makes it sound major. As we will see in the next unit, minor scales replace many of these major intervals with minor intervals, which is what makes them sound minor.

The Major Scale Method

If you know your major scales well, you can use the rule given above to help you to spell and identify intervals quickly. The major scale method of spelling and identifying intervals relies on your knowing major scales and key signatures very well. (If you are just learning major scales, the approach described here may not be as helpful to you.)

Tthe rule states that in a major scale the fourth, fifth, and octave above the tonic are perfect intervals. All other intervals above the tonic (seconds, thirds, sixths, and sevenths) are major. Let's apply this rule to a question: What is the interval from C to G? To answer this question, follow these steps:

Think of the bottom note of the interval as scale degree 1 or the tonic of a major key.
- In this case, the bottom note is C, so we will be thinking in the key of C major.
Ask yourself the question: Is the top note in the major scale of this key?
- Is the top note G in the C major scale? Yes. It is scale degree 5 in C major.
If the answer is yes, then the interval is either a major interval or a perfect interval (as stated by the rule). If the answer is no, then you will need to determine how it has been altered from major or perfect.
- In this case, the interval from C to G is a perfect fifth, because G occurs naturally in the scale of C major and is a fifth above the tonic.

Now let's try this same approach with the interval from E to G.

The bottom note is E, so we will be thinking in the key of E major.
The top note G is not in the scale of E major, since there is a G# in the key of E major.
In an E major scale, the interval from E to G# is a major third (see the rule), so the interval from E to G (a half-step smaller) must be a minor third.

What is the interval from D to C#?

The bottom note is D, so we will be thinking in the key of D major.
The top note C# is in the scale of D major. It is scale degree 7 in D major.
The interval from D to C# is a major seventh, since C# occurs naturally in D major.

Let's try one more: What is the interval from F to B?

The bottom note is F, so we will be thinking in the key of F major.
The top note B is not in the scale of F major, since there is a B♭ in the key of F major.
In an F major scale, the interval from F to B is a perfect fourth (see the rule), so the interval from F to B (a half-step larger) must be an augmented fourth.

Summary

That concludes our unit on intervals. Take a moment now to review what you have learned about interval size, interval quality, and interval inversion for the graded quiz that follows. You will not be required to identify intervals by ear in this quiz.