If you play through a Scale's notes starting from its Tonic note, each note that you play can be given a number. This number is that note's Scale Degree and is usually notated using Roman numerals. Here's an example of the Scale Degrees in the A Minor (Natural) scale.
Note Number Scale Degree A Minor (Natural) scale
1 I A
2 II B
3 III C
4 IV D
5 V E
6 VI F
7 VII G
Scale Degree Names
Scale Degrees apply independently of a scale's Key or Tonic Note. For example, the Tonic note will always be Scale Degree 1 (or the first note in the scale), whether the scale is A Natural Minor (Tonic Note: A) or D Major (Tonic Note: D). The Dominant Scale Degree will always be the 5th note in the scale, whether the scale is A Natural Minor (Dominant note: E) or D Major (Dominant: A). Each Scale Degree also has a corresponding name, as listed in the table below. One thing to note is that the 7th Scale Degree is called the Subtonic when you’re in a Minor (Natural) scale and it’s called the Leading Note when in a Major scale.
Scale Degree Scale Degree Name A Minor (Natural) scale
I Tonic A
II Supertonic B
III Mediant C
IV Subdominant D
V Dominant E
VI Submediant F
VII Subtonic/Leading Note G
Scale Degree Characteristics
Each note in a Scale has its own distinct characteristics which are based on its Scale Degree. Below are some descriptions of each Scale Degree and how each can be used.
The Tonic note is the Scale's boss and all the other notes revolve around it. It lets you know what key the melody's in and it's the strongest place to start or end a melody. As an end note, it can provide a real sense of completion, resolution and comfort. If you're writing a melody which is powerful and driving, try to use the Tonic a lot. Make less use of it if you're writing a sadder, more emotional melody.
The Supertonic is the next note up from the Tonic. It can make a melody sound uneasy and incomplete if the melody ends on it or stays on it for too long. It can be a great joining note in a melody which is moving from or to the Tonic.
The Mediant is the note which really lets you know when you're in a Major or Minor key. It's great at reinforcing the happiness of the major scale or the darker feel of the minor scale. This one note can transform a melody into a joyful celebration (major scale) or a sad introspection (minor scale).
The Subdominant is the third strongest note and a member of the Trio of Primary notes. It can have a more subdued strength compared to the other two Power notes (Tonic and Dominant) and it's often used as a variation for the Dominant.
The Dominant note is the military arm of the Tonic note (the Tonic would be the President in this analogy). It's the second strongest note in the scale and does a great job of reinforcing the Tonic note. Some of the most triumphant and powerful melodies have been created by alternating between the Tonic and Dominant notes.
The Submediant note is another note which can really define whether a scale is Major or Minor. In the Minor (Natural) scale particularly, its great at emphasizing the melancholy in a melody. It can be a useful device for moving to the Dominant note in a melody.
The Leading Tone or Subtonic note is the note below the Tonic and sounds like it's "leading" to the Tonic. Like the Supertonic, it can create an uneasiness in a melody which ends on it. The Leading note, particularly, can really build a feeling of suspense if you stay on it for too long. It’s also great at defining whether a Scale is Major or Minor.
Each Scale Degree has certain characteristics which gives it a unique function within a Scale. Developing a knowledge of these functions will give you a sense of insight when you're writing a melody.