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Science

Avalanches Simulated With 500,000 Ping-Pong Balls 56

Posted by timothy from the they-look-so-naughty dept.
An anonymous reader submits "Ping-pong ball avalanche experiments have been carried out for the last three years at the Miyanomori ski jump in Sapporo, Japan, to study three-dimensional granular flows. Up to 550,000 balls were released near the top of the landing slope. The balls then flowed past video cameras positioned close to the flow, which measured individual ball velocities in three dimensions, and air pressure tubes at different heights. The flows developed a complicated three-dimensional structure with a distinct head and tail, lobes and 'eyes.' See for yourself, it's quite interesting!"
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Avalanches Simulated With 500,000 Ping-Pong Balls More

Avalanches Simulated With 500,000 Ping-Pong Balls

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    • Re:Hmmmm... (Score:3, Interesting)

      by srmalloy ( 263556 )

      Were these supposed to be the avalanche victims?

      Actually, yes, but not deliberately.

      I remember running across references to this research before; apparently, the research staff, as part of a press conference, decided to stand on the slope when they dumped the ping-pong balls to give the photographers some dramatic photographs. After all, they were just ping-pong balls, right? Too light to do anything, right? Well, if you look at the image sequence one [hokudai.ac.jp],two [hokudai.ac.jp], and three [hokudai.ac.jp], you'll see that the researchers disc

  • Pic [tvacres.com]

    If you don't get the joke, you're too young :)

  • wtf? (Score:5, Funny)

    by kurosawdust ( 654754 ) on Tuesday January 27, 2004 @01:17AM (#8097083)
    I am very saddened that these people never thought of using this setup to simulate something orders of magnitude more profitable - the lottery!

    "Hey Bill, we've got tons of ping-pong balls and a very elaborate and sophisticated means of tracking their movement - what should we do with them?"
    "Uhh, use them to predict the Powerball results and retire on private carribean islands, unique ones of which we own for every day of the month?"
    "No, you fool! Avalanche research is clearly the way!"

  • A victim of this experiment? (Score:5, Funny)

    by weeboo0104 ( 644849 ) on Tuesday January 27, 2004 @01:28AM (#8097136) Journal
    The only tragic victim of this experiment was this man [go.com].

    A bespecticled bunny rabbit and moose were seen running from the scene.

  • The hardest part... (Score:5, Funny)

    by stefanlasiewski ( 63134 ) * <slashdotNO@SPAMstefanco.com> on Tuesday January 27, 2004 @01:30AM (#8097149) Homepage Journal
    I hate ping pong avalanches.

    The hardest part is digging yourself out with nothing but a ping pong paddle...
  • but somehow I doubt their webserver is ready for the ensueing avalanche of slashdotters!
    • me: [reading site] oh cool, ping pong balls. shitloads of em. shitloads of anything is good. clickety. oooh lotsa videos. hrm. "The files are mostly a few MB in size." cool. interesting.. uhh sure bottom camera. clickety.. save as.. program files, fine. clickety.. 33 FUCKING MEGABYTES??

      these motherfuckers got balls of steel, i say, serving 102 avi's at like 25 megs a pop. i would think doing something like that willingly implies confidence in one's ability to handle large amounts of bandwidth.

  • Hmm... (Score:4, Interesting)

    by shadowbearer ( 554144 ) on Tuesday January 27, 2004 @01:47AM (#8097217) Homepage Journal
    This is an interesting experiment and all, but it resembles a real avalanche about as much as computer climate models resemble real weather.

    A actual avalanche is orders of magnitude more complicated. It'd probably be easier, and much more informative, to simulate it on a computer, actually.

    It does make for some good eye candy, tho, and I'd bet it was a whole lot of fun. As a serious scientific tool, it's probably not very effective in this day and age, given the better tools out there.

    As a teaching tool, however, it has astounding potential, especially in primary education.

    Just as an aside, I've witnessed a few large avalanches. I was fascinated (and horrified) at the time; the fascination came from observing the complex flows introduced by various things such as the underlying terrain, trees, assorted rocks, etc. I remember thinking the last time that it was a good demonstration of fluid flow dynamics. The horror came from watching several skiers get caught up in the snow flow. They survived, thank Guh.

    (Disclaimer: IANAMathematician).

    SB

    • Re:Hmm... (Score:5, Interesting)

      by mhesseltine ( 541806 ) on Tuesday January 27, 2004 @02:21AM (#8097369) Homepage Journal

      From a recent article in DesignFax Magazine [manufacturingcenter.com], you might be surprised at the kinds of things you can model using simple bouncing-ball-like objects. Everything from giant dump trucks to laser toner.


      • That's an fascinating article; thanks. They were talking about computer software, tho (I read it in a hurry, did I miss something?)

        BTW, I believe that the truck on display at the Hibbing, MN Mining Museum is a 797. It's been a while, but the scale is right.

        SB

        • No, you didn't miss anything. The article is about software simulation and cross-industry licensing. However, it is a way to show how diverse problems can be modeled using similar techniques.

      • Re:Hmm... (Score:3, Informative)

        by pipingguy ( 566974 )
        you might be surprised at the kinds of things you can model using simple bouncing-ball-like objects

        Yeah, but I think the parent was referring to the lack of thermodynamics-type stuff, like snow or ice's reaction due to the heat of friction.

        Discovery.ca recently had a short spot on some kids studying freezing blown bubbles, see http://www.exn.ca/video/?Video=exn20040126-snowbub ble.asx.

    • Re:Hmm... (Score:5, Informative)

      by Cecil ( 37810 ) on Tuesday January 27, 2004 @04:10AM (#8097750) Homepage
      A actual avalanche is orders of magnitude more complicated. It'd probably be easier, and much more informative, to simulate it on a computer, actually.

      The same thing could be said about an avalanche relative to most of our fluid dynamics models. It is still orders of magnitude more complicated. Which isn't to say that our models aren't quite accurate, they are. But at the same time, they're merely a 'good enough' oversimplification of what's really going on.

      Fluid dynamics are an extremely difficult thing to model, and even more difficult to compute. They could challenge most of the supercomputers on the top500 list [top500.org].

      In fact, the top computer on there, Earth Simulator, (at well over double second place) has one of it's two primary objectives being the calculation of relatively simple fluid dynamics models across the Earth's entire oceans.

      So, to put it summarize my point here, the best fluid dynamics models we have are extremely expensive to compute, and they are still not perfect. The best way to better understand, and therefore better model, what is happening, is still to experiment with real physics. This experiment will help us develop faster-but-still-accurate models, or extremely precise models for fluid behavior. Either way, recording the locations of each 'particle' as they flow is actually research and will provide a solid set of data for future research to build on.

      Disclaimer: I work in the petroleum industry, and therefore only have experience with extremely high pressure/small scale fluid dynamics. My extrapolations may not hold true to the broader field of fluid dynamics.

      • Re:Hmm... (Score:3, Interesting)

        by gtapang ( 709419 )
        That is true. Aside from the difficulty in simulating such systems, it is also hard to do an actual experiment that will correspond exactly to your simulation.

        Furthermore, a model is exactly what it is-- an approximation of your actual complex system. There would be some details that would be left out to simplify the model while keeping the interesting phenomena intact.

        Using an actual system like the ping-pong experiment would still be an approximation to an actual avalanche but it provides a reasonably

      • Disclaimer: I work in the petroleum industry, and therefore only have experience with extremely high pressure/small scale fluid dynamics. My extrapolations may not hold true to the broader field of fluid dynamics.

        I found this interesting: Cheng Rotation Vane. [chengfluid.com]

        Intuitively, it seems to make sense: if a typical flow disruption pattern is known (and contained, as within a piping system), then it should be possible to counteract that disruption pattern. Of course, the upstream conditions need to be stable

    • Re:Hmm... (Score:3, Insightful)

      by Lars T. ( 470328 )
      First of all, look at what this post [slashdot.org] quotes from the site. The problem with avalanches (for the simulator) is that they are made up of a) snow (fluffy ice crystals) and b) air. They don't act like simple fluids.
      • The study of avalanche flow falls within a field known as Geophysical Fluid Dynamics. Yes, there are a lot of similarities; what you're describing is known as a "power snow" avalanche; "dense snow" avalanches are considerably more complicated.

        Some interesting reading

        avalanche.org [avalanche.org]

        SB
    • Yes, true, the mathematics are such that it's not much of a simulation, but damn that looks like fun.

  • Mining Simulations (Score:3, Interesting)

    by trinitrotoluene ( 713170 ) on Tuesday January 27, 2004 @01:49AM (#8097230)
    I went to the Open House for the mining engineering program at my university (Queen's [queensu.ca]) and one of the professors showed us how they use computer simulations to model rock interactions. The simulations modelled the behaviour and interactions of thousands of sample rock particles. Really interesting stuff. I guess this kind of test is where they get the raw data to develop these computer models.

    Mining engineering is also cool because there is a required explosives and blasting course in second year.

  • That picture [hokudai.ac.jp] totally looks like this animal [google.com]. Illustrating other evolutionary principles somehow?

    R

    • What evoluationary principle would that be? That badgers are made of ping-pong balls falling down a ramp?

      The similarity (I have to squint to see it; perhaps I'm lacking imagination) only illustrates that the brain sees patterns wherever it can. It's why people see Elvis in the fridge and hear their coffeepot talking to them.
    • If by "this animal" you mean "this animal's pelt", I'd have to agree. Perhaps we could postulate some theory about badger pelts being flat. And sheets of pingpong balls sliding down ramps being flat. The possible correlations are simply stunning. We could fill a box with badgers, and try and make an avalanche. Or maybe, try and mate badgers with avalanches to make a half-badger half-avalanche mix. Ferocious little beast. Cold, too. It could be the ultimate weapon on hilly terrain. We'd finally be a
    • so what you're saying is Badger, badger, badger [evilcouch.com]?
  • "Click on any of the pictures to get an enlargment."
  • Didn't Captain Kangaroo [tvacres.com] invent the Ping-Pong ball avalanche back in '55??
  • This would make an excellent addition to the spectacular gameshow 'Takeshi's Castle'. The opportunities for hilarity are just endless... maybe

  • Avalanche Rescue (Score:4, Funny)

    by fuzzybunny ( 112938 ) on Tuesday January 27, 2004 @08:30AM (#8098460) Homepage Journal
    This is pretty cool, sort of an "avalanche light" experience.

    They could rescue people with chihuahuas carrying cans of diet pepsi.

  • Though it's no doubt an interesting experiment that might lead to further research, it's a long way off from modeling real avalanches.

    Ice and snow crystals vaprorize, recrystalize, and form bonds in enormously complex systems, unlike ping pong balls, which just bounce off each other.

    An article documenting some of the research being done on avalanche snow's state changes and shifts in stability can be found here. [sciencenews.org]

  • Hey, you lost the ball again, Sureshot. Go find it.

    Okay....wait, here it is.
    And a second one!
    And yet another......and another....

    Oh oh, Ruuuuuuun!....
  • advanced 3d video and ping pong... its amazing this hasnt caught on earlier among the geek community!
  • ... 4 merry maids, 1 golf ball collector, and a fortune cookie. Can I have sauce with that?

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