I would have loved to take part in that experiment! I bet it felt funny. I'm surprised at the results. I guess the thickness of the water made it easier to hold on to the water with each stroke, offsetting the drag caused by the thickness? Just an amateur hypothesis! :)
What wasn't really mentioned is how far the swimmers swam in the tests. I could imagine your max speed would be close to the same, but I would guess if you swam any kind of distance you would tire out quickly due to the increased viscosity. I imagine this was outside the scope of the experiment, however.
maybe the viscosity of 'syrup' like water wasn't enought to create a difference. I bet there would be some effect the thicker the liquid. There is a lot of difference between a pool full of 'syrup' and a pool full of, say jello or mud! :D
everynight , water, water and swimming!
I am a fish. You all should know. All be it a slow, or moderate one, but a fish nonetheless.
PS_did I tell you guys that a few weeks ago I was doing 100's on 2 minutes! It was awesome! I was swimming next to this ironman swimmer, and she was so fast. Well, I was fast too, and have had more confidence ever since.
Best,
jerrys
I actually heard Professor Cussler on a CBC (Canadian Broadcasting Corporation) radio program a couple of months ago talking about this experiment. I am not a scientist, but on the program Professor Cussler's main point was that Reynolds Numbers (a measurent of the turbulence or viscosity of a fluid) have little or no effect on the velocity of swimmers. Acceleration however, may be an entirely different situation.
Like many others, I have been curious about this question for quite some time. Initially, I found the answer contrary to what one would expect. However, on re-examination, I would tend to agree with swimr4life as to the reasoning behind this phenomenon.
a well designed scientific study would have controled for distance swam and might have even included having the same swimmer swimming various distances. The part I think was poorly controled was the 'control condition.' The swim in the water pool was very close in time to the swim in the 'syrup' pool. In addition, it sounds like every swimmer swam in the 'syrup' pool first and the water pool second. To have been better the researchers should have had one group of swimmers swim in the water pool first then in the 'syrup' pool; while another group of swimmers would swim in the 'syrup' pool first and then the water pool. Breaking it down that was would have controled for fatigue and order of swim.
Okay, thats enough of that, too much like school!
Kirk,
Obviously you have a solid understanding about the fluid dynamics occuring here. In any event, this was what I remembered and/or the impression I was left with.
I apologize for my less than accurate post. Thank you for the clarification.
Originally posted by butterflybeer
Professor Cussler's main point was that Reynolds Numbers (a measurent of the turbulence or viscosity of a fluid) have little or no effect on the velocity of swimmers.
This can't really be true because Reynolds number includes velocity as one of its factors. Reynolds number is a unitless quantity equal to velocity multiplied by a characteristic length divided by viscosity. It is sometimes described as the ratio of intertial to viscous forces. You can't even calculate a Reynolds number without knowing the swimmer's velocity.
