Rick Sylvia wrote: > Brings up a thought, though, that he didn't (or hasn't yet) discussed. > Water temperature is a result of the speed of the atoms/ neurons/molecules > or whatever (I'm not all that scientific) - the faster they move, the higher > the temperature. So, if you are passing through a body of water with the > atoms (or whatever it is - humor me) themselves moving at varying speeds, > will it affect your speed? Seems like the colder water (therefore slower > moving atoms, and therefore less resistence / counteraction to other motion) > would allow for faster boat speed. [snip] No. Actually, the viscosity of water is mainly what affects the kind of drag you are describing: viscous drag. And, as the water's temperature is increased, the viscosity drops, so as the temp rises, the viscous drag decreases. I guess I disagree with Daniel Key that the change in density is more significant, inasmuch as the increase in density (have to move more mass aside) is offset by less hull in the water. I believe the decrease in viscosity will be more significant. > I'm also starting to wonder about water salinity, but we can save that one > for later.... Salinity has a very small effect on viscosity. Nothing like temperature. Probably not measurable under the usual test conditions, except that there will be less wetted surface area in salt water because it is more buoyant, hence less boat contacting the water. Note, however, per the comments of Daniel Key, that this is offset by the greater mass of the fluid displaced as you push you craft through water. Just my 2 cents ... although seems like others have half-dollars invested in the "paddle efficiency" debate. Read a lot of bad physics over the last week or so. -- Dave Kruger Astoria, OR *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************Received on Wed May 16 2001 - 18:55:13 PDT
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