RIP Pat Curran

 

Heavy, Round Bottom Stone Skip Further

 

 From NPR research news...

When skipping a stone across water, most people look for ones that are flat and light. Now, a new study suggests that curvier, heavier stones can also yield impressive skips. And these findings won't just help you improve your game, they could be applied to the real world, like helping make airplanes more efficient.

Ryan Palmer is an applied mathematician at the University of Bristol in the U.K. and co-author of the study, published this month in the Royal Society.

He and his colleague created a model to learn how shape and mass affect the way objects interact with water. They found that, when skipping rocks over a lake, "if you pick something that's slightly heavier, you get something called a super elastic response," Palmer said.

In other words, a heavier object could yield an impressive bounce.

"What happens is, the rock touches down on the water layer, and because it's heavier, it sinks down further and stays in contact for longer," Palmer said. "This increases pressure on that rock, which then increases the force that lifts it out, and you can get an almighty leap in this response."

Now, Palmer admitted that, though you may get a big leap with heavier stones, they won't result in as many skips as with flat ones. The results also depend on the stone's shape, because one that is too heavy may not work.

"So the take home really is, for a heavier rock that might sink, if it is slightly more curved, it may be more likely to skim," he said.

"Since starting on this work it's become even more irresistible to try and skim stones, and particularly just sort of picking the slightly weirder stones," he said. "Ones that aren't necessarily so flat."