Think about the sounds you hear every day. The sound of the garbage truck as it speeds past your house. The sound of your refrigerator buzzing in the background. The sound of whatever new construction they’ve started down the block. We think of these sounds as noise, and as noise being completely separate from music, but it’s not that simple. Starting in the early 20th century, composers expanded our definition of music to include all sounds, not just the ones we typically think of when we think of music. Thinking about sound this way has a profound effect on how we perceive the world, and can make for a much more interesting aural environment.