A.C.E. Guitar World

Scales

The word 'scale' originates from the Latin word 'scala', meaning 'ladder'. A scale is therefore a series of notes which progresses through an octave in alphabetical order.
We think of scales in terms of degrees, with the root note (or tonic) being the first degree.

Intervals

An interval is simply the distance between two notes. The sound of a scale will be characterised by the intervals involved in it.

Each degree of a scale is given a roman numeral:
I, II, III, IV, V, VI, VII, VIII. 
These are all relative to the major scale.

There are five different terms which can be used to describe the type of interval:

1. Perfect,
   
2. Major,
   
3. Minor,
   
4. Augmented, and
   
5. Diminished.
   

1. Perfect intervals are the unison, fourth, fifth, and octave.
   
2. Major intervals are the second, third, sixth and seventh.
   
3. Minor intervals are created when a major interval is lowered by a  semitone (one fret).
   
4. Augmented intervals occur when an interval is raised by a semitone.
   
5. Diminished intervals occur when an perfect or minor interval is lowered by a semitone.