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Recipe for Making Symetrical Holes in Water 174

Posted by CmdrTaco
from the welcome-to-sunday-morning dept.
scottZed writes "Danish researchers found a simple way to make curiously shaped air holes in a bucket of water. Simply rig the bucket to have a spinning plate at the bottom, and depending on the speed, you can get an ellipse, three-sided star, square, pentagon, or hexagon. The effect may help explain such shapes seen in atmospheric disturbances on Earth and other planets. One practical use: really trippy washing machines."
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Recipe for Making Symetrical Holes in Water

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  • Sloppy reporting. (Score:3, Insightful)

    by Anonymous Coward on Sunday May 21, 2006 @10:12AM (#15375705)
    TFA:
    Bizarre geometric shapes that appear at the centre of swirling vortices in planetary atmospheres might be explained by a simple experiment with a bucket of water.
    The bucket explains nothing - it might replcicate atmospheric conditions to the point where it will be a good model to aid in understanding atmosphereic conditions.

    This from a publication with the byline "the best in science journalism"

    Bah!
    • by MrShaggy (683273) <chris.anderson@hush.3.14com minus pi> on Sunday May 21, 2006 @10:50AM (#15375814) Journal
      Quoted from the article .." These natural structures have never been fully explained. Could they be produced by the effect observed by the Danish team? "I expect that similar conditions might apply in these atmospheric flows," says Bohr. But he admits that at this stage he doesn't understand the pattern-forming process well enough to be sure of the comparison.

      Swinney, meanwhile, thinks that the process is unlikely to apply to large-scale flows such as that on Saturn, but might be relevant to smaller-scale phenomena such as tornadoes."

      Seems that they realize that this is but baby steps, and there needs to be much more work done.
      • Re:Sloppy reporting. (Score:5, Informative)

        by m0nstr42 (914269) on Sunday May 21, 2006 @01:26PM (#15376423) Homepage Journal
        Seems that they realize that this is but baby steps, and there needs to be much more work done.

        Amen. I'm getting sick of people reading a /. summary of a summary of someone's legitimate results and deciding then and there that the original research (whose message is now 2x re-interpreted by the successive authors) is crap. These people do this for a living; many hold tenure positions at prestigious research institutions that are reserved for the brightest in their fields. Most of their really significant results appear in peer-reviewed publications. They're probably slightly more qualified to decide what is significant in their fields than you are.

        Popular media tends to mangle the crap out of stories in an effort to make it accessible to a wide variety of people. This is necessary for the sharing of information and the generation of public interest in scientific progress. If you're semi-intelligent and a particular story catches your eye, you should know enough to read between the lines a little bit. If you want to make any claims regarding validity, you need to find the original publications and make a slightly better assessment than a half-page web story can provide you with.
    • This is a simulation, not a competition.
      These are scientists at work, they've been doing science stuff for years.
    • I've never considered /. "the best in science journalism," and think you should think hard about life, the universe and everything if you do. It's more like a club where everyone is invited to throw shit at a wall and everyone can see it. Sometimes it's good shit, and sometimes it stinks. This is interesting shit, multicolored maybe...
      • Re:Sloppy reporting. (Score:2, Informative)

        by msparshatt (877862)
        I've never considered /. "the best in science journalism," and think you should think hard about life, the universe and everything if you do.
        The GP was referring to Nature magazine, which does describe itself as "the best in science journalism"
        • The GP was referring to Nature magazine, which does describe itself as "the best in science journalism"

          A magazine which let this little gem through the editorial process:

          "The researchers found that once the plate was spinning so fast that the water span out to the sides, creating a hole of air in the middle..." (emphasis mine)

          One might make the argument that they meant "spanned", but in context it seems obvious that they meant "spun". Either way, it's incorrect. The science might be peer-review
    • by i_should_be_working (720372) on Sunday May 21, 2006 @11:17AM (#15375915)
      It's how you decipher something that makes it an explanation.

      Einstein's equations of general relativity don't really explain anything unless you understand the math. To anyone else, they're just kooky looking symbols. To many people these may just be buckets with spinning water in them. To these researchers they may turn out to be explanations.
    • Venturing a guess that the speed that the false bottom is rotating at is related to the velocity that a vibration propagates through water, and the shapes are the result of resonance with the 'corners' nodes, and the edges antinodes.

      Thoughts?
      • Venturing a guess that the speed that the false bottom is rotating at is related to the velocity that a vibration propagates through water, and the shapes are the result of resonance with the 'corners' nodes, and the edges antinodes.

        Reminds me of an old joke:

        Q: How do you drive a Belgian nuts?
        A: You put him into a circular room, and tell him there are fries in the corner.

    • Easy to explain (Score:3, Interesting)

      What we're seeing are shapes caused by friction. As a moving fluid (liquid or gas) moves against something that is not moving, or is moving at a different speed, the friction causes waves just like those waves that surfer guys ride or the waves in the atmosphere caused by a wind blowing over a mountain.

      So why the different shapes? As the bucket speeds up, three things happen. There's a different speed differential between the bucket and the water, the water depth decreases and the extra g forces increase (e

    • Here is a link to cutting oddly shaped holes in a frozen lake. No bucket needed. ;-)

      ICE CARVING ROBOT

      http://jessehemminger.com/art-shanty/index.html [jessehemminger.com]

  • Interesting (Score:5, Funny)

    by Anonymous Coward on Sunday May 21, 2006 @10:15AM (#15375716)
    Aliens obviously use the plate to transmit geometrical patterns in an effort to contact us. This proves it beyond all doubt.
  • by coop535 (813230)
    But... how will this increase computing speed? Surely some scientist can make something up. Think of the children growing up right now with 3.2ghz dual cores!
  • Just a resonance? (Score:5, Insightful)

    by mangu (126918) on Sunday May 21, 2006 @10:22AM (#15375734)
    Well, if you have waves in the bucket, and the circumference of the hole is a multiple of that wavelength, then it's very natural that this phenomenon should happen.


    I'm curious about the researcher's name, Tomas Bohr, any relation to Niels?

  • Interesting Effect (Score:5, Interesting)

    by Anonymous Coward on Sunday May 21, 2006 @10:27AM (#15375746)
    It looks like the end result of system resonance set up between the harmonics and the properties of water. It would be cool to artificially vary the viscosity of the water with polymers, or add salts to increase specific gravity to note the affect on the pattern properties. OK, some of you are thinking, this guy is a nut but it just proves how never ending the learning process is as it relates to even the simplest things observed in nature. I like it.
    • It would be cool to artificially vary the viscosity of the water with polymers, or add salts to increase specific gravity to note the affect on the pattern properties.

      They beat you to it - they also did the experiment with ethylene glycol (about 15 times the viscosity of water). The same effect was observed, but only for low-order polygons. Not a huge difference in required frequencies over most depths, although the curves are rather less smooth than the ones obtained for water (presumably due to vortici

  • Practical (Score:5, Funny)

    by suv4x4 (956391) on Sunday May 21, 2006 @10:34AM (#15375759)
    One practical use: really trippy washing machines

    practical

    adj 1: concerned with actual use or practice; 2: guided by practical experience and observation rather than theory; 3: being actually such in almost every respect; 4: having or put to a practical purpose or use;
    • Pedantic (Score:5, Funny)

      by Anonymous Coward on Sunday May 21, 2006 @10:40AM (#15375784)
      pedantic

      adj 1: Like a pedant, overly concerned with formal rules and trivial points of learning; 2: Being showy of one's knowledge, often in a boring manner; 3: Often used to describe a person who emphasizes their knowledge through the use of vocabulary; 4: Being finicky or picky with language.
      • Re:Pedantic (Score:5, Funny)

        by suv4x4 (956391) on Sunday May 21, 2006 @10:48AM (#15375807)
        pedantic

        adj 1: Like a pedant, overly concerned with formal rules and trivial points of learning; 2: Being showy of one's knowledge, often in a boring manner; 3: Often used to describe a person who emphasizes their knowledge through the use of vocabulary; 4: Being finicky or picky with language.


        joke: n. 1. Something said or done to evoke laughter or amusement, especially an amusing story with a punch line. 2. A mischievous trick; a prank. 3. An amusing or ludicrous incident or situation.

        • Thanks for that, I nearly dropped my beer while laughing.
        • pedantic

          adj 1: Like a pedant, overly concerned with formal rules and trivial points of learning; 2: Being showy of one's knowledge, often in a boring manner; 3: Often used to describe a person who emphasizes their knowledge through the use of vocabulary; 4: Being finicky or picky with language.

          joke: n. 1. Something said or done to evoke laughter or amusement, especially an amusing story with a punch line. 2. A mischievous trick; a prank. 3. An amusing or ludicrous incident or situation.


          recursion: n. Mathema
          • pedantic: adj 1: Like a pedant, overly concerned with formal rules and trivial points of learning; 2: Being showy of one's knowledge, often in a boring manner; 3: Often used to describe a person who emphasizes their knowledge through the use of vocabulary; 4: Being finicky or picky with language.

            joke: n. 1. Something said or done to evoke laughter or amusement, especially an amusing story with a punch line. 2. A mischievous trick; a prank. 3. An amusing or ludicrous incident or situation.

            recursion: n. Mathe
    • practical

      adj 2: guided by practical experience and observation rather than theory; 4: having or put to a practical purpose or use;


      recursive

      adj see recursive.
  • This is real advance in physics!
  • A cake with a geometric-shaped bubble in the middle with cream filling. Either Rachael Ray [foodnetwork.com] will be all over this, or it will be quick fire challenge on next season's Top Chef [bravotv.com]. The possibilities are endless.
  • SymMetrical.

    Anyway, this isn't exactly a groundbreaking discovery.
  • One practical use: really trippy washing machine

    Yes, but only if you run it without any clothes. Very practical indeed!
  • The article says "At high enough rotation speeds, he says, a fluid will always experience some flow instability that creates a symmetrical structure."
     
    But doesn't the resulting symmetry show that what is achieved is a degree of stability? I've always thought it odd that in so called "chaos" theory, "chaos" is said to result in patterns (fractals) -- but doesn't the fact of a pattern belie "chaos"?
    • You may be confusing the original (ancient greek, biblical, etc.) idea of Chaos, as disordered formlessness. The modern idea of Chaos tends towards the idea of complexity. What becomes interesting is how very complex things can arise from simple conditions, and very simple things can arise out of complex conditions.
    • Re:Instability? (Score:4, Informative)

      by NeutronCowboy (896098) on Sunday May 21, 2006 @11:48AM (#15376022)
      You're confusing randomness with chaos theory. Randomness is essentially us saying "We might know the principles at work, but it's too complicated for us to make an accurate prediction on what is exactly going to happen." Brownian motion is one such example. We have a good idea on the physics behind it, but the huge number of interactions that take place mean that we can only predict the behavior of the entire system, not of single particles in it. Furthermore, single particles do not show a propensity to do anything in particular. You won't find random particles moving in circles, for example.

      Chaos theory deals with systems where we can calculate effects on single objects in the system, and where these objects exhibit non-random patterns. You mentioned fractals already (although strictly speaking, that's defined as a complex system rather than a chaotic one), and population growth patterns are another.
    • I think the instability they refer to in that line is the resonance. For whatever particular reason (any initial disturbance from absolute perfection will do), waves are forming that aren't fully random, and propogating across the bucket at a rate which is harmonically in tune with the rotation, causing these funny shapes. I would venture to guess that in either a fully stable or a fully chaotic system, the doughnut should be round, regardless of rate.

      Sounds like you've been reading a little bit of Micha
  • by Anonymous Coward
    When the dutch scientists spun the bucket ever faster, the shapes became even more interesting. It's a pity they were left out of the article. View them here:
    http://www.craigslist.org/sby/tls/163096693.html [craigslist.org]

    ~those crazy dutch scientists! what will the think of next!
  • Hey, I know these guys! Way to go!

    This just confirms my suspicion that the chance of a Nature publication is directly proportional to alcohol consumption. (Wonder what it takes to get on /.) OTOH, having an advisor from the Bohr family probably doesn't hurt.

    The academic lowdown:

    ArXiv preprint [arxiv.org]
    The full B. Sc. project [fys.ku.dk]

    Now, if only we could make 60gons...
  • Polygons on a Rotaing Fluid Surface [aip.org]

    "We report a novel and spectacular instability of a fluid surface in a rotating system. In a flow driven by rotating the bottom plate of a partially filled, stationary cylindrical container, the shape of the free surface can spontaneously break the axial symmetry and assume the form of a polygon rotating rigidly with a speed different from that of the plate. With water, we have observed polygons with up to 6 corners. It has been known for many years that such flows ar

  • mmmm tasty (Score:1, Interesting)

    by Bob_Geldof (887321)
    mmm ... tasty eigenmodes abounding. Congratulations. We study this kind of crap all the time in the Applied Mathematics program at Univ. of Washington. Can't imagine it's so different for other programs. That being said, I like the nice pictures. I've seen some interesting pictures where a thin layer of fluid is trapped between two cyliders. The inside cylinder is rotated and you can see through the outer one. At certain Reynolds http://en.wikipedia.org/wiki/Reynolds_number [wikipedia.org] numbers you get different forms,
  • Spelling Nazis 1, Headlines 0.
  • by layer3switch (783864) on Sunday May 21, 2006 @12:22PM (#15376165)
    "Harry Swinney, a specialist in pattern-forming fluid flows at the University of Texas at Austin, says the new observation is roughly in line with what one might expect."

    Wahhh~? Specialist in pattern-forming fluid flows at University of Texas at Austin? Heck I hope Mr. Swinney's parents didn't flush their saving down the toilet on his college education... oops, I mean, symetrically pattern-forming spiral downward flowing. ...yeah... the technical term.
  • The effect may help explain such shapes seen in atmospheric disturbances on Earth and other planets.

    Ex-NASA genius/nutball (you decide) Richard C. Hoagland has a page full of great pictures illustrating the above:
    Hyperdimensional Hurricanes? [enterprisemission.com]

  • Photos and video (Score:3, Informative)

    by Falkkin (97268) on Sunday May 21, 2006 @12:43PM (#15376253) Homepage
    Some better photos can be found here, along with a video. Unfortunately the video seems to show the vortex from its side rather than the top. Pretty cool though!

    http://dcwww.camp.dtu.dk/~tbohr/RotatingPolygon/ [camp.dtu.dk]
  • I have one of those new powerful toilets and been studying this effect closely.
  • Does this remind anyone of Riven?
    • Now someone go milk the beetles and give me a kortee'nea, I need to write some Ages badly :-) Oh, well, back to Povray it is then... :-P

  • This reminds me of the work of the Swiss doctor Hans Jenny in the 60s. Dr. Jenny sent audible simple sine waves through various media and photographed the patterns that would emerge.

    The results were often strikingly beautiful and symmetrical. His two books on the subject, full of high-quality imagery, were recently reprinted as one volume. He called his study of wave properties "cymatics."

    The photographs illustrate the multi-sensory aspect of all phenomena. Frequency and wavelength show their existen
  • Neat this might give a way to measure viscosity of an atmostphere of a distant planet. On the other hand, might interfere with trying to identify ET constructions. Every regular polygon we find we are going to now start looking at whether there is some rotating fluid involved.

  • There are some great videos [mac.com] of a similar behavior in a drop of mercury undergoing a cyclic surface reaction. It's a classic, called the "mercury beating heart." The drop will pulse in trianguloid and hexagonoid patterns. "Activity 5" is particularly good.
  • If you spun the bucket and the rest of the universe around the false bottom instead, would you get the same results? ;-)

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