The Projector Illusion |  EVERYDAY MYSTERIES

It's not necessarily an #everydaymysteries topic, because it's widely known how it works...but you have the resources to be able to show the physics of how whetstones work, which is probably my favorite display of simple things that work using multiple avenues of physics. Creating a vacuum with a water seal, the terminal velocity of metal and stone particles through water, material hardness and sheer...a simple, everyday object that shows just how incredible physics is, and more importantly, just how magical the interplay between different physics make something so simple work so well