I’m a big fan of simple ways to demonstrate complicated physical principles. For the ideas of potential energy and mechanical advantage there’s nothing better than the good old fashioned domino, lined up in file which only takes a single one to fall to start off a chain reaction down the line. What most people don’t know is that a domino can knock over another domino almost 1.5 times bigger than itself and that leads us to interesting demonstrations like this one:
In reality the dominoes’ power comes from you, the person who lifted them up in the first place. The act of knocking them over is simply a recovery of the energy you expended to lift them up, transferring it into kinetic energy. Being able to knock over the larger domino means you can amplify the amount of energy recovered which is commonly referred to as a mechanical advantage.
It’s a wonderfully simple demonstration, don’t you think?