Try Skimming Potato-Shaped Stones on Water, Mathematicians Say

This changes everything.

Amanda Kooser
Freelance writer Amanda C. Kooser covers gadgets and tech news with a twist for CNET. When not wallowing in weird gear and iPad apps for cats, she can be found tinkering with her 1956 DeSoto.
Amanda Kooser
2 min read
A small pile of rounded, vaguely potato-shaped stones in shades of gray and brown.
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A small pile of rounded, vaguely potato-shaped stones in shades of gray and brown.

These might not look like premium skimming stones, but they're worth a throw.

Amanda Kooser/CNET

The conventional wisdom for skimming (or skipping) stones on water is to find a round, flat stone to maximize your distance and number of skips. That's still good advice, but a pair of researchers has an addendum. Unconventional stones can generate beautiful bounces. 

Mathematicians Ryan Palmer of the University of Bristol and Frank Smith of University College London published a study on "the role of body shape and mass in skimming on water" in the Proceedings of the Royal Society A journal on Wednesday. The researchers developed a mathematical model to look at how objects of different shapes and masses interact with the surface of water.

It's not just about quantity of skips, but also about quality. Heftier, curved stones can generate impressive leaps. "If you've got a heavier rock, you can get a super-elastic response, where you get a single mega-bounce rather than lots of little bounces," Palmer told The Guardian. "There's this almighty leap out of the water." Palmer suggested trying out a stone that looks like a potato.

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It's easy to get lost in the fun side of the study, but Palmer highlighted its serious application in a series of tweets on Wednesday. "Our interest wasn't really on skimming rocks (though it is in scope), but rather the topic of aircraft icing - how ice builds up on aircraft during flight and how it may be mitigated," Palmer tweeted. "In this case, the skimmer is an ice crystal and the water a layer on the aircraft." 

You can put this study into action on your own. Find a nice body of water and a good selection of stones and see what you can get out of them. Try weird-shaped stones. Heavy ones with curved bottoms. What happens? Big bounces? Lots of skips? 

The stone is important, but successful skimming is also about good technique. The Guinness World Record for most skips of a skimming stone belongs to Kurt Steiner, who generated an astounding 88 skips in 2013. Steiner prefers thin, smooth, flat-bottomed stones. Guinness currently keeps records for most skips and farthest distance. Maybe it's time to add a category for highest bounce.