The above video is an old timey introduction to waves, using a mesmerizing mechanical simulator to demonstrate the main principles.
A basic understanding of waves can be helpful in inventing, since the principles are so similar across very different kinds of waves. Tesla was into waves, and they have applications in electrical theory. The way they build, cancel, resonate, and travel through different materials is central to understanding sound, music, vibration, earthquakes, tsunamis, light, color, economic prediction, and…well, I’ll stop listing things now, so you can watch the video in peace.