To the left, we have the root chord of the scale.
To the right, we have the most common names of the scale. (Some scales have many names).
The most common scales in western music are in bold.
Most scales are composed of 7 different notes, picked from twelve possible tones:
These tones are "equally spaced", they correspond to keys on a piano, or frets on a guitar, for example.
Their names are:
On some scales, a note can be considered diminished or augmented, meaning we set it respectively one semitone lower or higher.
More major or augmented tones will make a scale sound brighter.
More minor or diminished tones will make a scale sound darker.
For example, the major scale has a major second, third, sixth and seventh:
And the natural minor scale has a major second, but a minor third, sixth and seventh:
We have seen scales as a selection of notes, but we can also view them as a succession of intervals.
Major scale would be, from the root to the octave:
Whole step, whole step, half step, whole step, whole step, whole step, half step.
If we shift those intervals one step to the left, we get:
Whole step, half step, whole step, whole step, whole step, half step, whole step.
Then if we draw the notes this creates, we get a new scale: the second mode of the major scale (dorian).
We can continue and generate seven modes like this until we cycle back to the first mode.
According to this, every scale can generate as much modes as its number of notes.