at the moment i think i understand the modal harmony. but i am also aware there are certain scales that dont use just whole and half tone intervalls (i do not mean pentatonics because they simply miss out notes), like the harmonic minor/majour.

my guitar teacher told me thatthe reason the harmonic minor was created was the following. say you have a minor mode eg aolian, normally, modally speaking a 1 5 progression would contain two minor chords eg in A Aolian Aminor to Eminor. but for some reason in clasical musioc they thought it sounded better if the chord progresion was A minor to E majour. this means the third of the E chord was raise a semitone. this meant the 7th of the Aolinan scale had to be raised.

now it seem obvious that if the progression A minor E majour comes up you should use the harmonic minor, but when else can u use it? clearly the alteration in the scale will lead to strange chords like augmented and fully diminished ones, so again if u used these chords you should play in harmonic minor.

so overall what are some of these strange other scales, how can we apply them to music and how can you mesh diatonic and these other scales together?