Swimming As Easy In Syrup As In Water

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."

Comments

Forget swimming

[Anonymous Coward]

How about having sex in the stuff?

What about no very low viscosity?

[vasqzr]

How come I can't swim in air?

Re:What about no very low viscosity?

[|/|/|||]

Everybody knows that the trick is simply to hurl your body at the ground, but miss. Try it. The best way to do it is to have somebody distract you at the last moment.

Terminal Velocity

[Arrepiadd]

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

[be951]

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

[rusty0101]

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

[Proud like a god]

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.

where are the photos

[Anonymous Coward]

any magazine/newpaper/website that publishes a story like this without photo's should have their ministry of information publishing permit revoked.

Detials here

[lhaeh]

Going for the goo

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.

Re:resistance

[Holi]

I think the increased force used to pull your self through the water is offset by the increased viscosity of the fluid.

Bad analogy

[El]

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

[rusty0101]

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

[Anonymous Coward]

"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!

Why would it?

[charlie763]

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!

Next up:

[gardyloo]

The mechanics of Natalie Portman locomotion in thermally elevated, coarsely-ground, boiled maize.

Woot.

[a whoabot]

' "The best swimmer should have the body of a snake and the arms of a gorilla."

Edward Cussler
University of Minnesota '

TROGDOR!?!?

Underwater intercourse not such a hot idea

[MachDelta]

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 could very likely give her a nasty infection. Either way there's a risk of illness/injury, permanent damage (infertillity?), or possibly even death (your trick moves aren't so sexy when they cause internal bleeding).

So by all means, get hot and steamy under the waves, but when you're gonna introduce her port to your hard drive, you should probably do it on the beach (or dock or poolside or whatever). Remember kiddies, interfacing safely isn't just about using a latex firewall!


Oh yeah, and *insert joke about slashdotters and their sex liv... Actually, screw it, someone else can get the +5 funny. I'm gonna go whack off while dreaming about poolside sex instead. Ok, i'll probably just end up reinstalling drivers, but lets pretend like I went and... err... wait, lets not.

absolutely no evidence to support this!

[Anonymous Coward]

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.