Last article, I explained about modes and what they are. In this article, I will expand on your understanding of scales by getting you familiar with intervals and scale degrees.
Before we even get started, you MUST understand the difference between intervals, steps, and scale degrees. These are concepts that can be easily confused. But don't fret! I will do my best to enlighten you.
These are the LITERAL steps between notes. These are the MOST FUNDAMENTAL type of interval. From the "step," you get the half-step and every other interval in music. So steps are simply the building blocks of all intervals.
A scale degree is simply that. It is the degree -or NUMBER of the note in comparison to the root- of any note in any scale. The easiest way to practice understanding this, is to simply write a scale and number each note from 1 to 7. Then put 1 back on top.
C is 1, D is 2. E is 3, F is 4, G is 5, A is 6, B is 7, C is 1
Why is C1 at the top instead of C8? Without getting too technical at this point, just understand that EACH of the scale's seven notes should have its own identifier. So at this point, all C notes in the C scale are 1. All D notes in the C scale are 2. All E notes in the C scale are 3, etc...
All STEPS are intervals. But not all intervals are EXPRESSED in steps. Think of it like this: You wouldn't call the number 100, "ten-ten-ten-ten-ten-ten-ten-ten-ten-ten," would you? So normally, you use a QUALITY of SCALE DEGREE to express that interval. FOR INSTANCE:
Understand that, from C to A is exactly 4 1/2 steps.
But its INTERVAL is a major 6th (or maj6 for short).
We used its SCALE DEGREE to describe the interval. Since A is the 6th step in the C major scale, we label it as a major 6th.
I used the word "QUALITY" for the first time in the previous paragraph. So what exactly does a note's "QUALITY" refer to? For different scale degrees' intervals it means different things. But for now, the quality describes whether an interval occurs naturally in a major and/or minor scale. Obviously, the scale PATTERN defines whether or not a scale is minor or major. And we know that even SCALES themselves have a "quality" attached to them. What makes a SCALE also major or minor?
Answer: the 3rd scale degree.
Considered the most important scale degree, the 3rd literally defines the overall quality of the scale you are playing. A mode with a maj3 is a major scale. A mode with a min3 is a minor scale. That's all there is to it! Why did I say "mode" instead of scale? This is because three of the seven modes are "major" modes. The rest (except for the locrian) are minor modes. Given this, we can safely say that:
All the major modes are:
And all the minor modes are:
Let's go a step further and prove this (KEY OF C major).
Ionian is major. The distance between C and E is a maj3 (2 whole steps).
Lydian is major also. The distance between F and A is a maj3.
Mixolydian is major. The distance between G and B is a maj3.
Dorian is minor. The distance between D and F is a min3 (1 1/2 steps).
Phrygian is minor. The distance between E and G is a min3.
Aeolian is minor. The distance between A and C is a min3.
So now that you know scales can be major or minor, let's explore a few intervals. These will be maj3, p4, and p5. The p stands for "perfect."
A maj3 is 2 whole steps.
A p4 is 2 1/2 whole steps.
A p5 is 3 1/2 whole steps.
Why perfect? Why not major or minor? Firstly, lowering or raising a p4 or p5 DOES NOT make a scale major or minor. Secondly, they occur naturally THE SAME WAY in all of the modes except one. And finally, if you look at the major modes, ALL THREE start on perfect interval notes in comparison to their root! In C, those intervals are C, F, and G.
(C to itself is considered a perfect unison)
See how everything is starting to tie in?!!!
So to recap:
*STEPS are the building blocks of intervals.
*SCALE DEGREES are the numbered notes of a scale in comparison to the scale's root.
*INTERVALS are expressed mostly as a quality of scale degree.
*A MAJOR MODE has a maj3 interval from the 1st to the 3rd.
*A MINOR MODE has a min3 interval from the 1st to the 3rd.
*PERFECT intervals occur THE SAME in BOTH maj and min modes.
Bonus: the melody line of "Oh When the Saints Go Marching in" starts out with p-unison, maj3, p4, and p5 intervals. Now the title should make more sense!
In my next article, we will explore more intervals and the non-3rd
differences between modes.
Thanks for reading.