Why is the harmonic minor scale called 'harmonic' and the melodic minor is called 'melodic'?
if i had to guess, i would say it's because the harmonic minor scale (that means you use natural 7 but flat 6) seems to be what you get as a result of using (let's say it's the key of C minor) the G7 chord. you need that B natural note to make the G7 tick, and you might as well keep the Ab around (i.e. G7b9 or whatever). but sometimes melodies want to go 5,6,7,8 (so la ti do) kind of like that disney movie with the brooms dancing or whatever. so that would be the melodic minor scale. that one is usually only used on the way up