The Physics of How Lawn Mower Blades Cut Grass

The blades on a lawnmower aren't as sharp as you'd think (although they will hurt you), and they don't use an opposing force like scissors or a knife on a cutting board, so how do they cut grass instead of just pushing it down? The answer may surprise you. Destin Sandlin of Smarter Every Day takes us underneath a mower with a high-speed camera so that we can understand what's going on. (via Geeks Are Sexy)