What are scales and modes in music?
General definition
“Scale” comes from a Latin word which means ladder. A scale is the tonal basis of music. It is a set of tones from which you can build melodies and harmonies. The tones of a scale are ordered according to their pitch. Since scales create various distinctive moods, atmospheres and tonal flavors, there are as many scales as there are cultures around the world.
The major scale, minor scale and the church modes are all based on the diatonic scale. They consist of the same tones but the center tone (the tonic) is different.
The C major scale looks like this:
The Dorian church mode contains the same tones but the root tone is D:
In the same way, the Phrygian church mode has E as root tone. Lydian has the root tone F, Mixolydian has the root tone G, Natural minor (Aeolian) has the root tone A, and Locrian has the root tone B.
Recognizing scales by ear
A scale is a sequence of small intervals - in Western music, those intervals are usually tones (whole steps) and semi-tones (half steps). To identify a specific scale, you need to know its unique sequence of intervals.
Scales based on the diatonic scale will always consist of 5 tones and 2 semi-tones. Therefore, recognizing these scales can be simplified by identifying the position of their two semitones.