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Science

New Theory on Water Strider Propulsion 204

Posted by michael from the good-junkyard-wars-challenge dept.
capt.Hij writes "There is an interesting article at the Christian Science Monitor about how water skimmers are able to move the way they do. This new theory debunks the previously accepted theory and answers why smaller, younger water skimmers are also able to move the same way as their elders: 'As he looked into the question, he adds, he learned that the reigning explanation leaves an unsolved puzzle: If these tiny insects propel themselves in the way many researchers think they do, then baby water striders should go nowhere fast.'" There's also a BBC story with pictures.
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New Theory on Water Strider Propulsion More

New Theory on Water Strider Propulsion

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  • Dancing legs (Score:5, Informative)

    by Jarlsberg ( 643324 ) * on Friday August 08, 2003 @08:55AM (#6643993) Journal
    They move by using their mid leg pair as oars and the back pair as steering wheels. Previously, researchers thought they generated small waves, but baby water striders are too small to generate waves big enough to move on. The new research show that the waves are a biproduct of using the middle pair as oars, not the reason they move. Pictures here [nature.com], same news in norwegian here [science.no].

    • Wrong. (Score:4, Funny)

      by Anonymous Coward on Friday August 08, 2003 @09:13AM (#6644099)
      They move because they put their faith in jesus and he spirits them along over the water on the wings of christ.

      Damn dude, it said the CHRISTIAN science monitor.

      You remember.. the people who don't believe in evolution? Or stem cell research? Or cloning?

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

        by RobinH ( 124750 ) on Friday August 08, 2003 @09:38AM (#6644249) Homepage
        They move because they put their faith in jesus and he spirits them along over the water on the wings of christ.

        Damn dude, it said the CHRISTIAN science monitor.

        You remember.. the people who don't believe in evolution? Or stem cell research? Or cloning?

        That would certainly be most people's first impression, but I find that the CSM is probably the *most* objective reporting I've ever seen to date. There doesn't seem to be any particular bias that I can see. I'm glad I found the CSM, and I really enjoy reading it, even though I'm agnostic. I highly recommend everyone take a look with an open mind.

        • Re:Wrong. (Score:5, Funny)

          by Gzip Christ ( 683175 ) on Friday August 08, 2003 @09:55AM (#6644372) Homepage
          That would certainly be most people's first impression, but I find that the CSM is probably the *most* objective reporting I've ever seen to date. There doesn't seem to be any particular bias that I can see. I'm glad I found the CSM, and I really enjoy reading it, even though I'm agnostic. I highly recommend everyone take a look with an open mind.
          I second that. Compared with the mainstream press, it's utterly amazing how objective the Monitor has been throughout the whole water spider controversy.
        • The CSM may be one of the most objective news sources in the US, but that says more about the inadequacy of US journalism than the stellar achievements of the CSM.

          • Re:Wrong. (Score:2, Insightful)

            by jonadab ( 583620 )
            > The CSM may be one of the most objective news sources in the
            > US, but that says more about the inadequacy of US journalism
            > than the stellar achievements of the CSM.

            I'll second that.

            A lot of people are confused about the purpose of newspapers. The
            purpose of newspapers has nothing to do with discovering truth, and
            as a general rule journalists have at best a passing interest in
            truth or accuracy. The primary concern of journalists is to sell
            newspapers. In order to do that, they want to be perce
        • That would certainly be most people's first impression, but I find that the CSM is probably the *most* objective reporting I've ever seen to date. There doesn't seem to be any particular bias that I can see. I'm glad I found the CSM, and I really enjoy reading it, even though I'm agnostic. I highly recommend everyone take a look with an open mind.
          Well done, you've completed reading your first ever magazine. Now try your second...

      • Re:Wrong. (Score:5, Funny)

        by revery ( 456516 ) * <charles@NoSpam.cac2.net> on Friday August 08, 2003 @09:46AM (#6644294) Homepage
        You remember.. the people who don't believe in evolution? Or stem cell research? Or cloning?

        Yeah, those three are the same.

        Do you mean that they don't believe cloning is possible, or that they don't believe evolution is moral?

        --

        I don't believe in you...

      • Re:Wrong. (Score:2, Offtopic)

        by JonathanBoyd ( 644397 )

        You do realise there are plenty of Christian scientists, right? And that the overwhelming majority would have no problem with natural selection, which very obviously happens, but instead differ over whether or not we are the result of random genetic mutations, which quite a few non-Christian scientists are sceptical of as well.

        Now, as for stem cell research and cloning, what do you mean by 'don't believe in'? They accept the scientific theories concerning them, but think they are morally wrong. A different

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

        by overunderunderdone ( 521462 ) on Friday August 08, 2003 @10:27AM (#6644663)
        I think you may be misunderstanding where the name "Christian Science Monitor" is coming from. This is NOT a journal of science put out by Christians (creationist or otherwise) The CSM is a paper that was founded by a religous group founded in the 1800's known as the "Christian Scientists" or more formally "The Church of Christ, Scientist". The group is often considered a cult and is pretty much disavowed by both christians and scientists (and presumably christian scientists that are not "Christian Scientists"). From time to time they get in the papers because at the core of their beliefs is faith healing, or more accurately that there really is no such thing sickness anyway, so they will refuse medical treatment for themselves and their children.

        The Christian Science Monitor itself is a highly respected paper and while I think it is still officially owned by the church I think they have a hands off approach to running it and if they are using it for "evangelistic" purposes they use it by putting out a very high quality paper that by it's quality lends credibility to their group rather than using it as a polemic tool in itself. It's seems it's sort of like the Moonies owning the Washington Times rather than like an official organ of the church.
      • Damn dude, it said the CHRISTIAN science monitor.

        You remember.. the people who don't believe in evolution? Or stem cell research? Or cloning?

        Good joke, but the Christian Science Monitor does an okay job of reporting science topics. It's sure above the level of typical popular media, leaving alone Fox News's special "They didn't land on the moon because NASA is the government" division. Glance at CSM's coverage of this fossil find. [csmonitor.com] Hardly the whacko creationist extreme.

      • My hope is that one day we can have a story submitted from the CSM that doesn't generate volumes of insignificant chatter of over the name of the newspaper.

        You don't hear constant blah blah about the state or city of New York every time someone mentions the NYT. People tend to focus on the story. What a concept!
        • "Science" is the concept of examining evidence and basing rational theories on the evidence, then testing and refining those theories.

          Religion is irrational. It's about "faith" which essentially means, making theories with no evidence. In many religions people are actively discouraged from closely examining the evidence and the beliefs of the church.

          For a religious institute (or one whose name identifies it as such) to provide seemingly reasonable coverage of a scientific issue, including going so far as

    • Re:Dancing legs (Score:2, Interesting)

      by B'Trey ( 111263 )
      Thanks. I absolutely HATE articles like the one linked to in the story. In essence, it says "There was a previous theory which doesn't work. But we're not going to explain what the previous theory was because you're probably too stupid to understand it anyway. Now, there's a new thoery. But you're too stupid to understand it too."

  • Article is in Sci-Am (Score:3, Informative)

    by madaxe42 ( 690151 ) on Friday August 08, 2003 @08:57AM (#6644005) Homepage
    Very good article on this in scientific american, if anyone is interested!

  • A related article (as seen on Fark) (Score:5, Informative)

    by sczimme ( 603413 ) on Friday August 08, 2003 @09:06AM (#6644050)

    The Independent has a related article here [independent.co.uk].

  • Sculling... (Score:5, Informative)

    by LouisvilleDebugger ( 414168 ) on Friday August 08, 2003 @09:06AM (#6644053) Journal
    My mother was raised literally on the river (towboat pilot Dad), and knows how to "scull" (propel a small boat from the stern using a single oar or paddle.) The oar stays in the water and does describe a circular or elliptical path. It's about the weirdest means of locomotion I've ever seen, and doesn't look like it should work. But I can vouch that it does.

    I could never do it, although I was just a kid the last time I tried. Anyone here who can?
    • There are quite a few little black boats in venice [drewnoakes.com] which use sculling to move along, so yes, I think it's safe to say it does work.

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

      by HiQ ( 159108 )
      Yep I can, or at least could. When I was a kid I used to do this all the time in small rowing boats. And you don't actually make circular or elliptical movements, but something resembling an 'infinity' symbol (fgures eight). That is with your hands; the blade of the oar starts making an elliptical form through this, with the blade pressing against the water when you move 'along' the eight and slicing through the water when you turn the 'corners' of your figure eight.
      Sorry for the rather vague description, b

    • --- uber sculler (Score:2, Interesting)

      by madaxe42 ( 690151 )
      I've been doing sweep oar rowing and sculling for years... It's something that anyone can do, but few can master. The blade (the oar) moves in a roughly ellpitical track in the water, over a very small range, as the boat is propelled forwards. The range of motion is dependant upon the skill of the oarsman, and how he/she appiles pressure to the stroke. Too much too soon, and you 'rip', causing turbulence, and allowing the blade to move excessively through the water... Too little, and the blade won't lock on
      • Well, I may never understand all the cultural references in Miyazaki-san's Spirited Away [nausicaa.net] , but at least now I understand what Rin was doing in the scene where she is moving a barrel-shaped boat along, seemingly by doing nothing more than twisting what I thought was a rudder.

        "Sculling" -- my vocabulary word of the day. Thanks!

    • Anyone here who can?

      I'm not sure, but it sounds a lot like the action used to propel skates. That is, you don't go forward by pushing backward, but rather by pushing sideways and using a lever (the blade in my case, the oar in your mother's case) to redirect and gain mechanical advantage of the forces. It can be done on one skate, too, if you've got the balance for it.

  • Duh... (Score:5, Funny)

    by jeffkjo1 ( 663413 ) on Friday August 08, 2003 @09:08AM (#6644057) Homepage
    Everybody whose anybody knows waterstriders use anti-matter as propulsion.

  • A challenge (Score:5, Funny)

    by D0wnsp0ut ( 321316 ) on Friday August 08, 2003 @09:08AM (#6644059) Homepage Journal
    All I know about water skimmers/skippers is they're a bugger to hit with rocks, unless you get a really big, flat rock and even then you mostly just get yourself wet and still miss the skimmer.

  • Don't need to read it. (Score:3, Funny)

    by rde ( 17364 ) on Friday August 08, 2003 @09:08AM (#6644060)
    a) It's in Christian Science Monitor
    b) It's about skimming over the water.

    Chances are, Jesus features in the answer.

    • Re:Don't need to read it. (Score:5, Insightful)

      by The Ape With No Name ( 213531 ) on Friday August 08, 2003 @09:25AM (#6644182) Homepage
      Ummm. CSM is about as good as a balanced source as you will find and, despite the name, they don't do ridiculous things like you are talking about. My local rag [knoxnews.com] will probably run this on the Religion section this week rather than the Science page. You should know better. Kind of like Brit "Goebbels" Hume, questioning the source of an eyewitness account of American soldiers abusing Iraqi citizens, by saying, "What do we know about this paper The Manchester Guardian?" rather than saying, "Secondary sources have yet to confirm or deny the report from the Guardian.
    • Actually, stop-motion films of Jesus confirm the theory.
    • Actually people should note that this was originally a research article publishing in the respected journal Nature [nature.com]. Just because the story was later taken up the Christian Science Monitor is no reason to diss it.

  • A longer article [washingtonpost.com] mentioned a bigger strider they studied.

    I found it amazing that the robot was half the size of the Asian giant water strider.

    An 8 inch Water Strider might make a cool pet!

    What would it eat? How big of a pond would you need? Does anyone have experience with these critters?

  • Row row.. (Score:3, Insightful)

    by kmak ( 692406 ) on Friday August 08, 2003 @09:08AM (#6644065)
    Row Row Row your bug, rowing down the stream...

    But really though, if all it does is rowing, don't we already have tons of models that uses rowing? I mean, it's not electronic, but rowing's been around for centuries!

  • Amazing (Score:5, Insightful)

    by Vexalith ( 684137 ) on Friday August 08, 2003 @09:09AM (#6644066)
    I think it's an interesting reflection on humanity when evolution can throw up designs that we can't properly understand even with all of our apparent science and technology (bees, water striders, the thought process). It just goes to show that for every fact or theory we think we know there are far more that we don't, which gives me great confidence in the progress of human science and technology over the next few thousand years.
    • To be honest, I am quite amazed that you believe humans as a species will survive a few thousand years... turn on the news, man =/
      • To be honest, I'm quite amazed that humans still haven't caught on to the exponential progress [kurzweilai.net] meme, and instead extrapolate our current rate of progress linearly.

        Thousands of years? Try decades.

        Singularity or bust.

        --

    • It should be noted that research has been done into the whole bee/bug flying thing, and they have a pretty clear picture of how bugs fly. The bee one was poor science when it was done, using fixed-wing calculations on a moving-wing object. No less amazing, though, is all the stuff that has to be done to copy it, and the fact that it's controlled by something no bigger than, well, fly shit.

      Here [sciam.com] is an article about it. See how /. readers don't do that, a synopsis: Flies keep their wings at the edge of s
  • ... I've pondered how waterbugs move around on top of the water. In my naivete, thinking there could possibly be no connection between something that actually matters like a cure for cancer and water striders, I dismissed this ponderance for something shiny.

    The shiny thing was a small robot that could possibly make use of this method of propulsion. Then I realized there were only 10 of us in the world and rejoiced as this great find was made public and made available to the popular geek culture. Now thousa

  • Do they have them everywhere (Score:3, Interesting)

    by Cackmobile ( 182667 ) on Friday August 08, 2003 @09:15AM (#6644112) Journal
    Are water striders one of those bugs they have everywhere like flies/mosquitos/etc. We have them in oz, here in the UK, in asia and the US. Anywhere else.

  • Now that... (Score:4, Funny)

    by Akardam ( 186995 ) on Friday August 08, 2003 @09:19AM (#6644141)
    ... is a bug!

  • Surface tension is cool! (Score:3, Interesting)

    by PhysicsExpert ( 665793 ) on Friday August 08, 2003 @09:37AM (#6644246) Homepage Journal
    A few of my colleagues have been looking into the effects of surface tension in various liquids and you'll be amazed to learn what you can do if you have the right circumstances.

    H20 doesn't have that much surface tension becuase of its low valency, but other liquids such as bromine are held together by strong Van der Waals attractions meaning that they have much stronger surface tensions. In one famous experiment at MIT researches showed just how strong the surface tension could be by placing a cat onto a large pool of bromine and observing that not only did it not sink but that it could also move abount (albeit with difficulty). Some people have suggested (tongue in cheek) that if Jesus could have introduced bromine into the red sea then that would explain how he could have walked on water.
    • It's not the Red Sea, it's the Lake of Gennesaret.

      The Rea Sea was the one where the surface tension didn't hold up to the weight of the Egyptian Army ;)

      Just my E0.02.

    • Re:Surface tension is cool! - Troll Alert!!! (Score:5, Informative)

      by pdp11e ( 555723 ) on Friday August 08, 2003 @10:06AM (#6644484)
      Now this is a troll if I ever saw one. Bromine is the only liquid nonmetallic element. It is a heavy, mobile, reddish-brown liquid, volatilizing readily at room temperature. It is toxic comparable to chlorine. The surface tension of bromine is LESS then that of the water.
      Cat (or any other live being) in a large pool of bromine has a life expectancy of a few minutes. And yes it would sink.
      • Not so! For you see, the cat can stay aloft as long as it still has lives to use. It would only sink and die following the expiriation of its last life. ;)
      • Cat (or any other live being) in a large pool of bromine has a life expectancy of a few minutes. And yes it would sink.

        Oh come on... are you calling into question the veracity of the famous MIT experiment? How about some facts? Bromine has a density [lbl.gov] of 3.12 g/mL--over three times that of water. People have no problem floating in the highly-saline water of the Dead Sea, which has a density [jordanembassyus.org] of about 1.2 g/mL. So no, it wouldn't sink.

    • Good day, PhysicsExpert. I was wondering if you happened to know where my esteemed colleague PhysicsGenius went off to... I miss his information and insights on the fascinating field of Physics.

      And thanks for reminding me of the MIT experiment; I've been meaning to duplicate that with my pet hamster, but I keep forgetting about it. Perhaps I'll stop by the local druggist today and get a bottle of bromine.

  • Impressionist Insects (Score:4, Interesting)

    by unfortunateson ( 527551 ) on Friday August 08, 2003 @09:54AM (#6644363) Journal
    Go take a gander at the original BBC article [bbc.co.uk] with the photos. The one with the blue dye in the water showing the eddies created by the movement is practically a natural reproduction of Van Gogh's brushwork!

    It's like having insects do impressionist painting. Truly beautiful. If I can find a high-res photo, I think I've got my new wallpaper.

  • Oh my... (Score:5, Funny)

    by tkittel ( 619119 ) on Friday August 08, 2003 @09:54AM (#6644369)
    It seems that we have a Christian source of information related to walking on water?

    At least it is their own IP :-)
  • Now: bugs walking on water.

    Next up: evolution!
  • There's also a BBC story with pictures.

    Ooooohh Pictures!

  • Dr. Bush (Score:4, Funny)

    by fruity1983 ( 561851 ) on Friday August 08, 2003 @10:16AM (#6644563)
    "Doctor" and "Bush". After the last few years, I have a lot of trouble visualizing that...

  • Probably known about for a long time (Score:3, Interesting)

    by panurge ( 573432 ) on Friday August 08, 2003 @10:32AM (#6644700)
    In England water striders are known as water boatmen. Boatman=person operating small scull boat for short distance water transport. This suggests that the "sculling" action has been recognised for a long time.

    Sometimes it takes a lot of scientific training to work out things country people have known for a long time - digitalis, willow bark, cowpox, and all those interesting rain-forest rmedies the drugs companies are "patenting".

  • This is easy. Go to Egypt, and then go down the hole at the far left side of the level. Hiryu will find the Aqua Boots there. ...Sorry, NES flashback.
  • From my point of view. My background is in fluid mechanics, and even though I've only obtained my master's, I couldn't have told that scientist where the momentum was transfered.

    The same thing for aircraft: tip vortices and a bound vortex on the wing alter the direction of the incoming air, which changes the air's momentum and provides lift. And all that happens because of friction between the molecules of air on the surface of the wing, and their neighbors directly above them. Then THEIR neighbors di
  • I love the title of the article in CSM - Propelled by "Sculling".

    Reminds me of a few uni students I knew...

    (In case it is a local vernacular - "sculling" is a colloquial expression for downing ones drink without in one go).

    Q.

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