The science of skipping stones


#1

[Read the post]


#2

Of course the simple blurb of an article doesn’t give a link to the actual research paper. Fortunately google scholar is your friend, and one of the co-authors has a copy of the paper on his academic website. Unfortunately there is no simple analytic solution to the mathematical model, it’s a non-linear ordinary differential equation that has to be integrated numerically.


#3

Yay! No paywall!


#4

During WW II skipping stones inspired Barnes Wallace with the idea of the Dam Buster bombs, so he did a lot of practical research on optimal angles/shapes/spin for objects bouncing on water:


#5

"You throw and throw and throw again, and you just get free,’’ Bocquet says. ‘‘You can empty your mind with this gesture.’’

You say throw, I say toss, but pretty much.


#6


#7

During World War II, the British Royal Air Force skipped bombs at German dams to avoid underwater torpedo nets.

Yeah, but…

The bouncing bombs were spun around a different axis than stones. I’m no physicist; can anyone explain (simply!) whether that means it’s the same mechanism?


#8

20 degree angle. Admittedly, at that end of things, degrees and gradians are pretty close (18% = 20 degrees) but the two should not be conflated.

/pedantry


#9

Science?
You don’t need science if you start with my artisinal skipping stones.


#10

It’s because water has a much higher index of refraction, so if you hit it lower than the critical angle… oh, wait, that’s light, not stone.

What if the stone was going the speed of light?


#11

In a vacuum of course.


#12

Well, then you’d have to use spherical cows.


#13

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