God, I love scientists. Nature has a story about Christophe Clanet, a physicist who recently calculated the perfect angle for skipping stones. To do so, he built his own stone-skipping machine:

The motorised catapult fires aluminium discs into a two metre-long pool of water. High-speed video cameras record the moment of impact, which normally lasts for less than one hundredth of a second.

The result? “To achieve the maximum number of rebounds, the angle between a spinning stone and the water should be about 20 degrees, advises Clanet: ‘This is the magic angle.’”

Interestingly, this actually has real-world implications. As Clanet points out, his system might help physicists model the way that spacecraft bounce across the planet’s atmosphere on their descent back to Earth.

Of course, I’d imagine that there are a bunch of other factors one could build into a stone-skipping model. When I was a kid, part of the fun was going out to a lake in really rough weather and trying to see if we could skip stones across two-foot-high waves. Actually, I bet stone-skipping would make a fun online Flash game. Has anyone ever seen anything like that?

(Thanks to SciTech Daily for this one!)