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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."
How about having sex in the stuff?
How come I can't swim in air?
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?
any magazine/newpaper/website that publishes a story like this without photo's should have their ministry of information publishing permit revoked.
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.
I think the increased force used to pull your self through the water is offset by the increased viscosity of the fluid.
Sorry, teleporters just kill you and then make a copy. A perfect, soul-less copy.
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...
"Freedom means freedom for everybody" -- Dick Cheney
"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!
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!
Welcome to the land of the free...pay toll ahead...no photography...please open your bag...
The mechanics of Natalie Portman locomotion in thermally elevated, coarsely-ground, boiled maize.
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 the same speed as you are. As you move further out, there is a gradient where the layers of the fluid are moving at slower speeds until the edge of the boundary, where the fluid is moving at the ambient velocity (0). The effect of these layers moving at different speeds is a resistance to movement due the viscosity of the liquid. It's easier to explain with pictures.
And you can't swim in air because you sink to the bottom.
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 evidence the topic needs changing, right?
Of course, this would all be for the advancement of science. No really.
--
24 wars since WW2: Creating fear so rich people can profit.
' "The best swimmer should have the body of a snake and the arms of a gorilla."
Edward Cussler
University of Minnesota '
TROGDOR!?!?
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.
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
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.
Resistance is futile...
Well, I was ALMOST on topic ;-)
LongTail SSH Brute Force analysis tool is here!
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 slow down. The only point being made was that Newton was wrong and the swimming motion of humans compensates for various viscosities.
It would be interesting to see the experiment performed with various swimming animals to compare the efficiency and adaptability of their swimming to ours.
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.
Huh?