On 04/20/2011 02:36 PM, Jed Rothwell wrote: > > Stephen A. Lawrence <sa...@pobox.com <mailto:sa...@pobox.com>> wrote: > > > Say WHAT? You just "proved" that all pipes inside the ecat are > *frictionless* !! > > > Actually, if you read what I wrote previously, and repeatedly, I said > that a tiny amount of heat transfers, in the milliwatt range, from > friction. However that is many orders of magnitude smaller than you > can measure with a calorimeter designed for kilowatt-scale reactions.
Yes, that's true. But I was taking issue, specifically, with this sentence (emphasis added): "_The water does not /slow down or stop/ between those points, so *none* of the pump energy converts to heat._" My point was the /speed/ doesn't change but the /pressure/ does, and that equates to a drop in the energy carried by the fluid, and that energy drop shows up as heat. (Tiny, /tiny/ amounts of heat.) > > You would need a microcalorimeter to detect the friction of water in > these pipes, even at 1/L second. > > > > In fact, what you would find if you could take *extremely* precise > pressure measurements all along the pipe, is that the pressure of > the water DROPS, very gradually, as you move along the pipe away > from the pump. > > > That's what I said. Oh, well, sorry -- then I didn't understand. > > - Jed >
