TUNES AND RIFFS USE SCALES AND MODES AS RAW MATERIAL. A scale has musical potential, like an unexplored country. The space is too huge to map, and there’s no Google Street View for it yet. So you have to use a combination of instinct and creativity to make the journey worthwhile. (Or you can just copy other people, and maybe make a few changes.)
You make music with scales in two ways:
You play notes one after the other to make a line, shape, riff, tune, melody, hook, or whatever other word you want to use that means more or less the same thing.
You play notes at the same time to make a blob of sound called a