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Stone Skipping the Scientific Way
Quirk writes "National Geographic has a bit on the scientific analysis of stone skipping. Using a machine launching aluminum disks Lyderic Bocquet, a physics professor at the University of Lyon, and his colleagues discovered the 'magic angle' of 20 degrees as that required to maximize skipping. 'Jerdone Coleman McGhee of Wimberley, Texas, holds the current Guinness Book of World Records title for a 1992 toss that yielded an impressive 38 bounces across the Blanco River in central Texas'"
what they'll be doing at the next foo camp ;)
USE='clever' emerge -u sig
I am horrible at skipping stones, but the best I ever got was on lake oneida up in NY right before it froze over (I think it was like 10 skips; yeah, I suck). I wonder how much the other type of degrees (temperature) effects things . . . physics/chem geek want to wax eloquent?
What we should REALLY be trying to figure out is how to skip more massive stones. That's the next step.
This one time, me and some people were skipping stones *hardcore* style. We got the biggest flat rocks we could lift and tried to spin them. Usually they just glided, but sometimes they would skip fairly high.
Of course, once the government got hold of this technology, they would put it to use bombing Iraq.
Esoteric reference.
Why do a scientific analysis of something when you ignore the #1 variable: The Stone.
...good to see tax payer/student dollars at work
Zillions of years of waves busting up the tough rocks has polished them all smooth and flat. This makes for some of the best skipping stones ever. We're talking about an endless supply here.
Some of the piles I've seen reach 3 to 4 feet in height and run for hundreds of yards down the beach; all made up of beautiful rocks. If you're lucky you can find some other nifty stuff like beach glass or driftwood. And not so nifty stuff, like dead fish and RIAA jackets.
that a human can skip one 38 times, but there is no mention on how many times the machine they built was able to do it. Just watch, this is gonna lead to some wacky robotics competition where teams try to construct different robotic launchers to see which can skip more times or longer distance.
"0101100101? It's just jibberish. *looks in mirror, gasps* 1010011010@!? AHHHHHH!!"
...geeks bringing a stone skipping machine to tweak and experiment with while they go camping with their Wi-Fi gear. Can't we have a normal camping trip? =)
My innocent childhood hobby has been ruined with the introduction of science and actual calculations! Not to mention that I've only ever been able to get like five skips. *runs to hide*
Try actually thinking for yourself. It's quite refreshing.
You centrally located people haven't experienced stone skipping until you have been to the ocean. Easy to get 15-20 skips in a calm inlet. Dense salt water makes it that much easier.
I'm sure at the dead sea you could really make 'em go.
... that some people have entirely too much time on their hands. :)
File under 'M' for 'Manic ranting'
I doubt it. It was done by some French scientists. So I doubt your congressman should care.
The article suggests that this is the first time this type of problem has been scientifically studied. As far as I know this kind of problem has been very thoroughly studied for aerospace purposes: a planet's atmosphere is the pond, and a spacecraft is the stone. A google search for 'skip trajectory' shows up lots of serious research.
Warning: not for the faint-hearted!
Any disc golfer or ultimate frisbee player can tell you that changing the shape or weight of your disc can very significantly affect its dynamics. It could be that they've only found the ideal release conditions for the particular disc they were testing with.
Here is a news article in the science journal which has the original report.
Infuriate left and right
http://www.rootstrikers.org/
This is what science is all about. Mars? Please. Nanotubes? Come on! Stealth? Get real. Now stone skipping, that's worth at least a Master's dissertation... This has the possibility to advance toy technology YEARS!
"Who are in control, they are not in control of anything - they don't even control themselves!" - Glen Beck
Only in GW Bush's homestate would National Geographic stoop this low. Next they'll be flinging cow pies.
the allies figured this out in ww2. Nazi dam bombing
How can this be applied to real-world applications? Are they going to redesign jet-skis with this information? Or surfboards or body-boards?
Those are a few things this research could possibly apply to, can anyone give me examples of others?
I ran a benchmark on my quantum computer, now I can't find it anywhere!
The massive spinning bombs that were designed to bounce along the water before sinking and exploding in front of a dam? That technology was developed and used successfully in world war II by the english.
I ran a benchmark on my quantum computer, now I can't find it anywhere!
I recall watching a documentary about Barnes Wallis, a British scientist who during WWII invented and "perfected" a dam busting bomb. A rather large (multi ton) spinning cylinder full of explosives that would be dropped from a plane at remarkably low altitude over water directly at a dam at high speed, resulting in the bomb's skipping, like a stone, until it would collide with the dam. The bomb would then sink, but it's spinning motion would keep it tight to the dam until it exploded.
Wallis' research involved countless stone skipping tests, that inevitably resulted in the discovery of the perfect angle.
The bombs themselves enjoyed marginal success, succesfully destroying 1 of 3 objectives, if I'm not mistaken.
http://simscience.org/cracks/dambusters.html - Interesting videos and more information.
I mean, the trailing edge is the edge that will hit the water first if you're talking a 20 degree angle, and if the stone skipped, the center of force would have to be behind the stone's center of gravity (otherwise it would sink).
If it skips soon enough, it could be far enough behind the center of gravity to cause the stone to flip. But I doubt it happens all the time, because I can't see getting it to flip the same speed every time. If it doesn't flip by about 180%, the stone would soon hit at a bad angle and sink. The chances of even getting three or four skips in a row would probably be ridiculously small, but I can get at least that many skips fairly consistently.
Getting a golf ball to skip...now that takes talent. Yeah, that's it. Talent...
We recently sailed out to Ft Jefferson in the Dry Tortugas. We read where the soldiers would heat cannonballs to red hot and shoot them at enemy ships. They even made an oven with 4 magazines in it for the job. They used layers of wet and dry padding between the poweder and ball in the cannons. My pics don't say what size balls but they were one of 12, 18, or 32 lbs.
These balls would skip along the saltwater and bury themselves in the ships at waterline level where the seamen couldn't get to them. The balls would then burn through the boats hull, hopefully starting a fire.
See, there were even geeks back then with a lot of time and resources on their hands. This must have taken a lot of practice.
Also visited Fort Pulaski outside of Savannah GA. These 2 forts were designed to be very similiar in so many aspects. But there is no mention here of this kind of ball skipping. Where Ft Jefferson is surrounded by water, though, Ft Pulaski only has it near in a 45degree arc, and that's more than a 1/4 mile away. The ships channel is out of cannonball range these days; maybe it wasn't back then.
Mysterious Rock Movements
January 12, 2003
Lake Superior, Minnesota
Scientists and local authorities are struggling to explain the sudden rise in the level of lake Superior. After long investigation the rise was attributed to a big pile of mostly flat rocks that somehow made their way into a pile a few meters from the shore. There was also a smaller pile of not-so-flat rocks much closer to the shore.
Invstigators attempting to trace the people behind this strange event have only a few puzzling clues to guide them. The whole beach appears to bave been trampled by hundreds of thousands of people. The only clues to their presence is all those strange conical pieces of tin-foil with the base roughly the size of a human head. There were also a number of RIAA jackets nailed to tree stumps and impaled with darts.
Darl McBride, strangely showed up and shoved the following quote down our throats: "I'm not sure who is behind this, but I'm certain we own the intellectual property. We can't tell you quite what the property is or how it was violated, but please send us $699"
Every year the folks who put out The Annals of Improbable Research , formerly The Journal of Irreproducible Results, formerly The Worm Runner's Digest hands out ten IgNobel Prizes for scientific achievements "which can not or should not be repeated". It's sort of a Feast of Misrule for science.
If they can give an Ig for the first MRI images showing conclusively how men and women's bits fit together during coitus and a scientific study on the optimal way to dunk a biscuit in coffee, then by G-d this deserves one too!
The man who never alters his opinion is like the stagnant water and breeds Reptiles of the Mind -- William Blake
The whole point of scienctific research is to find new technologies and (maybe) a use for them. You never know how this research could effect the world. Wakeboarding and surfing come to mind, as well as applications with the slashdown of spacecraft. Who knows?
The stone is usually spinning around an axis that is more or less vertical. The angular momentum of the stone makes it much more difficult to flip over via forces exerted by the water interface. In order to have it flip over, the axis of the spin now has to become horizontal requiring a tremendous torque.
A stone fired at a lake with no initial spin might easily tumble in the manner you're describing, but probably wouldn't skip nearly as well.
((lambda (x) (x x)) (lambda (x) (x x))) http://www.endpointcomputing.com a scientific approach to custom computing.
I'm sorry, but when I've skipped stones, half of the challange is finding the right flat stones. This whole experiment takes the fun out of it and turns it into a joyless exercise.
I'd certainly hope this isn't going to lead to 'skipping stones' at the Olympics, or a standard skipping stone, produced by AMF and Wilson. Can't something just be fun without the jocks getting involved?
A Good Intro to NetBS
It seems to me that they're missing several somethings that are fairly important (other than the physics of the stone): the velocity and spin of the stone (to say nothing of the water surface's dynamics).
:P
That said, my personal record was achieved when I was 12 at a cub/boy scount camp. It was in a little river/creek (maybe 10 feet across, no deeper than 1' in most parts, with lots of smallish smooth disc-shaped stones perfect for skipping). My group was out hiking, and we had a competition. Everyone else was picking more roughly-shaped stones off the shore, and not venturing into the water.
Having grown up watching my uncles skip stones on their lake since I was very young, I probably knew a thing or two about stone skipping that the others didn't, simply by example. At any rate, I took a step or two out into the water, and grabbed the smoothest stone I could find.
This was all after the scout master said the person with the most skips gets a candy bar. IIRC, I was the last to have my turn at winning the candy bar. Everyone started bitching about how I was cheating because I didn't take the rock from the shoreline. (bah!) I got into the water, and got as close as I could to the water, and threw the stone upstream like a frisby.
The end result: 23 skips, at least half an hour of people trying to come close to half as many skips, and a candy bar for me back at camp. And a dozen pissed off cub scouts for 4 more days.
~/ssh slashdot.org ssh: connect to host slashdot.org port 22: too many beers
the 'aviation engineer' in question is Barnes Wallace. The 'Bouncing Bomb' was used in the successful attacks to flood the industrial Ruhr Valley in Germany, by destroying the reservoir dams. He chose 220mph, rather than 25mph. I guess the stalling speed of a Lancaster bomber is a little high for that.
I've skipped stones (at a precise 20degrees) at Ladybower reservoir in Derbyshire, UK, where the practise flights were made - like many WW2 bombing operations, there was no attention to 'collateral damage':
Guardian Unlimited
Two dams out of the three targeted - the Mohne and Eder - were breached. Thirteen hundred civilians were killed, including nearly 500 slave labourers from the Ukraine - mostly women. Local towns were flooded, trains washed off their tracks and six electricity stations put out of action.
'This writing business. Pencils and what-not. Over-rated if you ask me. Silly stuff. Nothing in it' - Eeyore
I skip the Stones whenever they're in town.
I'm not paying $150 a ticket to see a zombie like Keith Richards.
and no one is going to believe it,(and I can't prove it) but I once managed 42 (answer to everything if you read douglas adams) on the River Mersey, mind you this was in the '70's and the river was more polluted then