Friday, October 07, 2005

Ignoble Prizes and Swiming in Water vs Syrup

To follow up on our previous discussion about swimming in H_2O versus swimming in D_2O, I bring to your attention this year's Ig Noble Prize in Chemistry to Edward Cussler and Briand Gettelfinger at U. Minnesota and U Wisconsin. The award winning paper...
"Will Humans Swim Faster or Slower in Syrup?" American Institute of Chemical Engineers Journal, Brian Gettelfinger and E. L. Cussler, vol. 50, no. 11, October 2004, pp. 2646-7.


Blogger Justin said...

So, can anyone get to the article? Do they agree with Eric?

10/07/2005 09:42:00 AM  
Blogger Eric said...

Sorry, I didn't realize that my university proxy server was important for reading the article.

Well, they didn't explicitly consider swimming in D_2O.
A few quotes...

"We noted that swimmers go faster in salt water than in fresh water because they are more buoyant"

I didn't know that, but I think my arguement would lead to that conclusion. For comparison, this site claims ocean water has a density 2.7% greater than pure water. Whereas the desnity of D_2O is about 11% greater than that of H_2O. So the effect in D_2O should be significantly greater.

But that wasn't their experiment...

"We chose to thicken water with guar gum because it is readily available in a food grade and causes few allergic reactions."

"he viscosity of the aqueous guar solution was... about twice that of water."

" The density of these guar solutions was within 10-4 g/cm3 of that of water, so buoyancy changes were insignificant."

"Swimming speed in guar solution is the same as in water."

"The standard deviation between lengths for the... competitive swimmers is 2.4%, the same as that recorded by their coaches in normal workouts"

So to a doubling of the viscosity (while holding the density constant to 0.1%) does not affect human speed to about ~3%

They also include a discussion of turbulence that begins
"...imagine a swimmer going 2 m/s who is 1.8 m tall with a frontal area of 0.1 m2 and a wetted area of 2 m2..."

They then give a brief explanation that the Reynolds number is ~600,0000, turbulence, constant drag coefficient, force ~ velocity squared, etc.

However, in their experiement the swimmers took a gliding start due to the small length of their pool. If I remember correctly, this was the weakest assumption in my analysis, since we know that in a Olympic race they often get a big jump and spend a good while underwater.

So fortunately, there is more exciting research to be done in this field. Maybe I should mention this as a research interest in my job applications. :)

10/07/2005 02:05:00 PM  
Blogger Justin said...

Eric Ford.

Fields of interest:
- Extrasolar planets
- The effects of varying media in human swimming perormance

Now I'm suspicious that your earlier analysis was borrowed from this paper :-P

10/07/2005 05:14:00 PM  
Blogger Justin said...

On the other hand, perhaps we can alert the Ig Nobel committee to the parallel, independent theoretical groundwork for this experiment on this blog. Maybe they'll add you to the award as an Honorable Mention.

10/07/2005 05:16:00 PM  
Blogger Eric said...

Oh dear. I hope they wait until I get a job.

10/07/2005 05:49:00 PM  
Blogger Vincent said...

So they didn't use any actual syrup? That's a disappointment.

10/08/2005 12:37:00 AM  

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