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It's funny. Laugh. Science

Swimming As Easy In Syrup As In Water 94

Posted by timothy from the chlorine-ratio-adjustment dept.
chthonicdaemon writes "Nature is running a story about scientists at the University of Minnesota who proved that swimming speed is not a large function of the viscosity of the liquid. To do this, they thickened the water in a pool with guar gum. Fun ensued. This is the type of thing that usually keeps to thought experiments. Interesting to see someone prove it."
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Swimming As Easy In Syrup As In Water More

Swimming As Easy In Syrup As In Water

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  • It seems like a thicker liquid that is not near solid would be easier to swim in since you can effectively pull yourself forward with the same strokes more at a time. In other words, your body moves more than your arm does in the stroke, the intent to the stroke.

    The article says that neither produced faster times consistantly, however, so whatever. I don't plan on swimming in syrup. That's nasty.

    Chris

    • Re:resistance (Score:4, Interesting)

      by Holi ( 250190 ) on Wednesday September 22, 2004 @12:00PM (#10319915)
      I think the increased force used to pull your self through the water is offset by the increased viscosity of the fluid.

      • The thing is they should have increased the distance as swimming through syrup will be more tiring as you will have to expend more energy to move through the more viscous fluid.

        So sez the guy who did not read the article.

        and yes I am replying to my own post.

  • Forget swimming (Score:4, Funny)

    by Anonymous Coward on Wednesday September 22, 2004 @11:43AM (#10319709)
    How about having sex in the stuff?
    • Actually, you're not supposed to have sex underwater. Its fine for the guy, but keep in mind that a girl's plumbing wasn't really designed to be plumbing. Pushing too much water up inside her with too much force could cause damage to sensitive things like her fallopian tubes. And even if you go at it gently, there's the risk of literally flooding her. Get enough water up the fallopian tubes and it could pass through the infundibulum abdominal ostium - meaning she gets water in her abdominal cavity, which co

      • absolutely no evidence to support this! (Score:4, Interesting)

        by Anonymous Coward on Wednesday September 22, 2004 @05:32PM (#10324030)
        Actually, you're not supposed to have sex underwater. Its fine for the guy, but keep in mind that a girl's plumbing wasn't really designed to be plumbing.

        This is a false rumor spread by that Canadian-grandmother-turned-sex-therapist who has the womens' network show (which is hilarious, incidentally. Trust me.) Ask YOUR doctor about any advice you see on the show before you put it to practice ("I saw it on TV, it must be true!"), okay?

        People have been having sex for centuries in the water- lakes, ponds, rivers, oceans, hot tubs, pools, jacuzis, showers, bathtubs- you name it, people have had sex there- and there's simply no evidence of all these injuries you claim(death? Infertility? Riight. I've even seen people claim women could get air embolisms!) A UK women's scuba newsletter asked women divers about their experiences, and surprise- nobody had an injuries.

        If anyone who is actually qualified to speak on this subject can present ANY case evidence of this happening in substantial numbers(linkage, please!), I'll shut up- but I think the parent poster is full of nonsense and these "dangers" are about as "dangerous" statistically as catching, and dying from, West Nile Disease- if at all.

      • Re:Underwater intercourse not such a hot idea (Score:2, Informative)

        by Anonymous Coward
        I think under normal circumstances the cervix forms a pretty darned good seal. I suspect you would only really need to worry shortly after a gynological exam.

        Supposition of course, I'm not a doctor. But right before my second was born, the mucous plug came out and her water broke - and it made a fairly loud, "Bang!" The baby was sealed in until ready.

  • What about no very low viscosity? (Score:4, Interesting)

    by vasqzr ( 619165 ) <vasqzr@@@netscape...net> on Wednesday September 22, 2004 @11:44AM (#10319733)

    How come I can't swim in air?

  • Terminal Velocity (Score:3, Interesting)

    by Arrepiadd ( 688829 ) on Wednesday September 22, 2004 @11:49AM (#10319790)

    If the viscosity of a fluid doesn't influence your speed through it how come you have a terminal velocity while falling in air but not in vacuum.

    And, as someone said, why can't we swim in air?

    • Re:Terminal Velocity (Score:5, Informative)

      by be951 ( 772934 ) on Wednesday September 22, 2004 @11:59AM (#10319900)
      If the viscosity of a fluid doesn't influence your speed through it...

      Because that is not actually true. The article seems to describe the experiment fairly well, but the underlying theory quite poorly. If objects (or swimmers) were simply launched into the fluid, the difference would be much more obvious. The key point in the experiment is that you gain about the same amount propelling yourself as you lose due to greater drag for the limited range of viscosities investigated (very high or low viscosity could produce different results).

    • Re:Terminal Velocity (Score:5, Informative)

      by rusty0101 ( 565565 ) on Wednesday September 22, 2004 @12:01PM (#10319929) Homepage Journal
      Both are actually the same question. Your body is not structured to "swim" in air. Swiming in air is what we call flying. In all cases forward motion is derived by using force to put stuff that was in front of you, behind you, and the reaction is you going forward.

      You are not designed to "float" or "fly" in material as lightly viscous as our atmosphere. The relative density between us, and our lack of a structure designed to produce lift are working against us.

      That's not to say that you can't go a long way towards solving this problem. The suits some skydivers use, with pannels betwen their legs, and from legs to arms, allow them to glide a lot further, and have a different perceived terminal velocity than skydivers without these pannels.

      Our largest failing is that we do not have a wishbone to hang the necesary musculature on for us to convert our arms to wings. This is true even if our bones were filled with air rather than marrow. (side effect, unless the marrow is given a new portion of the body to reside in, our immune system would have some serious issues.)

      -Rusty

      • Re:Terminal Velocity (Score:4, Interesting)

        by Proud like a god ( 656928 ) on Wednesday September 22, 2004 @12:37PM (#10320332) Homepage
        But when you're travelling through air you're not only countering drag but attempting to create enough lift to counter your weight. Purely forward swimming through air in a weightless environment wouldnt require some energy diverted to counter your weight, quite unlike flying today.
      • side effect, unless the marrow is given a new portion of the body to reside in, our immune system would have some serious issues

        Note: Although bird bones are mostly hollow and filled with air, they still contain marrow (but the marrow cavities are smaller).
      • I remember seeing a documentary on TV once where they calculated/estimated the size of the flight muscles (mainly the pectorals) necessary for humans to fly. Needless to say, they would have to be pretty huge. They reckoned that the anchoring ridge on the sternum for these muscles would project out about a foot!
    • > If the viscosity of a fluid doesn't influence your speed through it how
      > come you have a terminal velocity while falling in air but not in vacuum

      Unrelated. Terminal velocity has to do with the coefficient of dynamic
      friction versus the acceleration due to gravity ballancing eachother out.
      Swimming speed is orthogonal to the gravitational acceleration, due to your
      buoyancy, and as far as the coefficient of friction, the friction of your
      torso and head is offset by the friction of your limbs going the o
    • If the viscosity of a fluid doesn't influence your speed through it ... why can't we swim in air?

      Air is a fluid? You learn something new every day...

      Seriously, viscosity of a fluid is one thing, but the very definition of "fluid" means that the molecules are packed an awful lot closer together than they are in the atmosphere. That's (one of) the problem(s) with swimming in air.

      • You're confusing "fluid" with "liquid" -- a very common mistake, but a mistake nonetheless. Fluids can be gaseous, liquid, or even made up of solids -- anything that can flow. Solids can act as a fluid if they're small enough for the given environment (analysis of traffic bottlenecks is one example of the application of fluid dynamics on a macro scale).

  • where are the photos (Score:4, Insightful)

    by Anonymous Coward on Wednesday September 22, 2004 @11:52AM (#10319827)
    any magazine/newpaper/website that publishes a story like this without photo's should have their ministry of information publishing permit revoked.
  • IMHO it's one of the coolest experiments I've heard about.
    And there's no need to discuss the problem in the future.
    I just hope somebody reproduce the experiment to verify it.

  • Detials here (Score:5, Informative)

    by lhaeh ( 463179 ) on Wednesday September 22, 2004 @12:00PM (#10319907)
    Going for the goo [umn.edu]

    It gives you an idea of how they setup the experement.

    The team devised a Rube Goldberg-like contraption using a large green plastic garbage can, a drill with a mixing head, and a length of PVC piping. The device permitted them to pump the guar gum solution directly into the pool, an operation that took about four hours on a Saturday afternoon.

  • Bad analogy (Score:4, Funny)

    by El ( 94934 ) on Wednesday September 22, 2004 @12:01PM (#10319925)
    try running with a large newspaper held in front of you and see how much more difficult it is.Well, yeah, because you keep running into things because you can't see! Also, a newpaper does not remain flat when subjected to wind resistance. Methinks using a stiff piece of cardboard or even a windsurfer sail would be a much better example...

    • Re:Bad analogy (Score:5, Informative)

      by rusty0101 ( 565565 ) on Wednesday September 22, 2004 @12:36PM (#10320328) Homepage Journal
      It is an even worse analogy than that. The cause of the resistance is not the flat face of the surface, but the flat back of the surface causing turbulance, and drag.

      Put a cone on the back of whatever you are trying to push through the air, and the resistance will be significantly lower.

      -Rusty

  • Best swimmer (Score:3, Funny)

    by Anonymous Coward on Wednesday September 22, 2004 @12:03PM (#10319952)
    "The best swimmer should have the body of a snake and the arms of a gorilla," recommends Cussler. Well, as long as we're making ridiculous analogies, I think the best swimmer would have a propeller coming out of their ass!
    • Sounds like Trogdor would have an easy time winning swimming meets, if he decided to go that route.

      Or would his little wings cause too much drag and counteract the properly-shaped body?
  • It's not exactly something you'd want to dabble your feet in on a summers day...

  • Why would it? (Score:4, Interesting)

    by charlie763 ( 529636 ) on Wednesday September 22, 2004 @12:24PM (#10320194)
    It's really the ratio of the force of friction of you body moving through the water compared to the force of friction of your arms moving in the opposite direction.

    Think about this: If you try to swim in space with its near zero friction, do you go anywhere? No, you don't because there is nothing to push against.

    One thing that might cause a more viscus liquid to slow a swimmer (ignoring fatigue)is the resistance of the liquid to moving behind a swimmer. This creates a vacuum and would be move force for the swimmer to fight.

    I'd like to see them try this experiment in molasses so we can really see if there is a difference!
    • Ok, I guess you're smarter than Isaac Newton then.

  • Next up: (Score:5, Funny)

    by gardyloo ( 512791 ) on Wednesday September 22, 2004 @12:32PM (#10320282)
    The mechanics of Natalie Portman locomotion in thermally elevated, coarsely-ground, boiled maize.

    • They should have a school for moderators. The parent comment is not off topic; it is funny, if you know the history of crazy comments on Slashdot. I appreciate how the comment tries to make the subject look scientific.

      --
      Bush: Spending money the U.S. doesn't have [brillig.com] to try to make his administration look good.

    • I think there is a need for another data point in this research. What about doing testing in a more viscous fluid? I'm sure that there are a considerable number of Slashdot readers that would like to do research on the very important question of whether Natalie Portman could swim faster in hot grits.

      How can a moderator say the parent comment is off topic when so many Slashdotters would like to be on this topic? More philosophically, how can Natalie Portman be off topic? If she is off topic, that is evid

  • I wish we could've tried this in our fluid's lab!

    I doubt you would get the same effect if you continued to increase the viscosity. The human body has relatively high "form drag" which is resistance due to the shape. At lower viscosities, this would be the significant force. At higher viscosities, the effect of "skin drag" begins to win over. This is caused by shear stress in the boundary layer. In an attempt at English, that means that the fluid immediately in contact with your skin as you swim is moving

    • My friends and I have had an argument similar to this for a few years now and we can't seem to come to a conclusion. If you filled a swimming pool full of Jello and let it gel then jumped into it and sank to the bottom, would you be able to swim yourself out?
      • Take inspiration from this experiment -- and find out!

        Don't forget a breathing tube and/or rope, just in case...
        • I'm not sure that I could pull off creating that much Jello. You'd have to have a giant boiler to mix up the batches then pour it into a swimming pool in the winter time so it would set up. By my quick calculation, it would take 1.3 million 3 oz. boxes of Jello to create enough Jello to fill a 750 cubic meter pool (25m x 10m x 3m). I think this experiment might have to be performed on a smaller scale.
  • Theoretically, would it be possible to try this the other way around with a fluid less viscous /a>than water? Like, say, ethyl alcohol or acetone or methanol... [wikipedia.org]

    • Theoretically, would it be possible to try this the other way around with a fluid less viscous /a>than water? Like, say, ethyl alcohol or acetone or methanol...

      Theoretically, yes. But I can think of some practical reasons not to attempt swimming in a pool filled with any of these liquids...

      • I believe the Sandia Z-Machine is filled with some sort of cooling or dialectric (i can't remember exactly) fluid that is low-density enough for swimming to be impossible. If you fall in, you're supposed to hold your breath, walk to the side, and climb up the ladder.

        I'm having trouble finding the article that talked about the fluid, but you can at least have a look at a picture of it running (you don't want to swim in it while it's on, I imagine...)

        Picture [csparks.com]
        • You're right, the Z-Machine (z-pinch) has open pools filled with oil. Oil is less dense than humans typically are, and so anyone falling in would fall to the bottom quickly.

          They'd have to do just exactly what you said to get out.

          --PM
  • Oh well. Guess I should just stop my research now, since these guys have the Science IgNobel just about wrapped up.

  • Woot. (Score:5, Funny)

    by a whoabot ( 706122 ) on Wednesday September 22, 2004 @02:12PM (#10321581)
    ' "The best swimmer should have the body of a snake and the arms of a gorilla."

    Edward Cussler
    University of Minnesota '

    TROGDOR!?!?

  • The trick is to fill the pool with guar gum without getting caught.

    Silly scientists...
  • I seems they also tried guar gum in their server. Anybody got a mirror site?

    I can just envision that a conversion similar to this happened:

    Teacher: Guys, where are you going with our lab guar gum? That stuff is expensive!

    Students: Oh, um, just to have some fun with it in the pool.

    Teacher: To justify the cost, let's turn this into a science experiment on viscosity, okay?

    Students: Gotcha! But can we do the paper-work tomarrow instead?

    Teacher: Sure. Go have fun.
  • I wouldn't be surprised if part of the reason for this experiment was to explore new forms of resistance training for elite swimmers.

    Since this didn't work out, does anyone know if someone is working on high-drag suits for training, kind of the opposite of the shark-skin like suits used for competition?

    • All you need to increase drag for swim training is something that acts like a parachute in the water. There are products like a drogue chute that are dragged behind the swimmer attached to a belt. There are also belts that have "pockets" on the sides which are positioned to open out and collect water, increasing drag, as one swims forwards.

      No hi-tech materials needed I'm afraid ;-)

  • I can't believe nobody's said it yet.... (Score:3, Funny)

    by CSG_SurferDude ( 96615 ) <wedaa.wedaa@com> on Wednesday September 22, 2004 @10:34PM (#10325990) Homepage Journal

    Resistance is futile...

    Well, I was ALMOST on topic ;-)

  • The conclusion of the experiment was NOT that "viscosity has nothing to do with swimming speed" but rather that within a certain tolerance of viscosity, the human form performs equally well. This just means that for certain viscosities, humans are able to provide enough force by the swimming motion to propel themselves forward.

    TFA certainly does not say that viscosity doesn't matter. After all, we can't swim on concrete, nor through air, and common sense says that a bullet fired into mud will drastically
    • >This just means that for certain viscosities, humans are able to provide enough force by the swimming motion to propel themselves forward.

      I read it a little bit different.

      I figured the thick liquid provided more force to push against, therefore negating the drag cause by the think liquid.

      But like you said when the liquid becomes too thick it will slow down the swimmer.

      But I could be wrong.
  • Wasn't there a movie where they filled a pool with Jello and had a a guy dive in for the effect. I seem to recall something about the stunt guy having a time getting back out.

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