What's your favorite bit of physics that most laypeople are unaware of? It could be something commonplace that doesn't get the attention it deserves, or something really exotic that doesn't tend to make it to the masses. For context, I've been on kind of an "outreach" kick with my friends and family, and having a lot of fun with it. I'm looking for some good subjects/phenomenon that are dramatic or quirky or simply underappreciated. I feel like lots of people see books about string theory and cosmology and frontier science, but it seems to me like there is so much stuff that we understand really well that people aren't aware of, and it needs to get more attention! Some examples of my own to start things off: For me, I remember when I first learned about Coriolis forces and how they produce the rotation of hurricanes. That was a really awesome connection for me freshman year, realizing that the same effect that makes it hard to play catch on a merry-go-round could cause the distinct spirals of these-planet-scale storms. This is a fun one to explain to people because it extends something relatable to something incredibly dramatic. Another big moment for me was when I first noticed that the bubbles in my coffee were attracted to my stirring stick, and to each other. I still get probably an hour of entertainment out of this when I have some free time in the morning. On the more exotic side, I'm going through my first Solids course now, and I'm constantly awed by the microscopic explanations for basic, taken-for-granted properties like the reflectivity of metals, although I haven't really come up with a good way to relate stuff at this level to family and friends. If anyone has any clever way to explain some of this more esoteric physics to laypeople, I'd love to hear it.