This year I've been working through a topic that I thought I understood pretty well - acoustics. As I went through the process of writing and planning some videos on the topic, I quickly realized that there were some sizable gaps in my own understanding. It's amazing how clearly and completely the act of teaching or explaining something reveals the shortcoming in my own knowledge.
I set out to make a video about the acoustic wave equation, but came to realize that I didn't fully understand forced harmonic motion, or for that matter simple harmonic motion (SHM) - something I learned for the first time in high school, ten years ago! In the process I was fortunate enough to come across Feynman's lectures in physics - an absolutely wonderful resource that I wish I had been exposed to earlier. I've never read someone who has as much fun explaining physics. Truly inspiring.
Thus far, this exploration has results in this two part video series on harmonic motion. I try to have some fun along the way, while digging deeply into the underlying assumptions and math. The connection between circular and harmonic motion was particularly fascinating me, this is something I try to spend some quality time on, and resulted in the title of the video.
Finally, harmonic motion forms a basis for many more advanced topics, and I hope what I have done here is to provide some clear and practical ways of thinking about the topic.