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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."
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).
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.
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
You never know...
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
You never know...
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 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.
Dumb ass: women _can_ get air embolisms, though it's not common.
o r/oral_sex.html (near the end)
Evidence:
http://www.goaskalice.columbia.edu/1859.html
http://www.brainyencyclopedia.com/encyclopedia/o/
I couldn't find any evidence for the water thing though.
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?