It's definitely an observable phenomena. The effect of heating up the faucet valve may be more significant than you think. Certainly you have observed some types of faucets that greatly reduce the flow when hot water reaches them. Another thing I can think of that may account for a sound change, is that hot water has very little dissolved air in it compared to cold water.
Physics class was one of the most traumatic experiences of my life, and I didn't learn much there. But ... hot water is higher pressure, moving faster, higher frequency across the joints? Kind of like a steam whistle?
I have definitely heard it in my shower.
Ice should actually be less thick, considering that water expands when freezing.
Sounds strange, but true in a way. Hot water is more excited.
Ah, but, (to continue this physical science mental masturbation session), it depends on how you define "thick." :-)
Per mass of water, ice is going to be thicker dimensionally because of its lower density. Which was probably Bub's clever point.
Best Regards,
-- Todd H.
Yeah, there's little doubt in my mind now -- it's the bubbles. The hot water is supersaturated with dissolved air. It's agitated by passing through the faucet and then subjected to a pressure reduction. All that air is released in the form of bubbles. So what we hear is the difference between a stream of water and a stream of something approaching a foam -- very different sounds.
I must say, solving this little mystery has been MOST satisfying ;-)
This already has most of the heat of hot water (the TOTALLY ARTIFICIAL) 0-point used in both Fahrenheit and Celsius temperature scales hides this fact.
There is a big difference between 200 degree coffee water and 130 degree tap water. I wouldn't be to sure that the coffee effect is what you are hearing.
Take a bottle or can of soda. Heat it up to 130 degrees, shake the container (c.f. water forced through faucet) and remove the cap (water exiting spout)...
Yes, I realize that's an extreme case but there's little doubt in my mind that there will be significant bubble formation with the hot water faucet that could easily account for the change in sound.
I have had times when it was relatively quiet until the hot water arrived, so I think its supportable the bubbles themselves (during formation, or going through a restriction) make noise.
Dave
Hmmm, I don't think that's an effect I've observed but you make a good point. I can see how that might happen.
Oh the pain! The heartache! My "thickness of water" theorem has been disproved!
And I thought I would be jo> >
Sorry, I noticed the ambiguity too late.
I will follow your logic as soon as you tell me how much heat "weighs". Heat is just the average kinetic energy of the molecules of the substance. More heat=more energy. More energy=larger distance between molecules. Larger distance between molecules=Less Density.
That is the correct logic you are look> Follow my logic here:
Re: how much heat "weighs".
I'll get back to you as soon as I finish reading the article that the following abstract describes:
On the Weight of Heat and Thermal Equilibrium in General Relativity
Richard C. Tolman Norman Bridge Laboratory, California Institute of Technology, Pasadena, California Received 30 December 1929
In accordance with the special theory of relativity all forms of energy, including heat, have inertia and hence in accordance with the equivalence principle also have weight. The purpose of the present article is to investigate the thermodynamic implications of the idea that heat has weight. In particular an investigation is made to see if a temperature gradient is a necessary accompaniment of thermal equilibrium in a gravitational field, in order to prevent the flow of heat from regions of higher to those of lower gravitational potential.
A preliminary non-rigorous treatment of this problem is first given by attempting to modify the classical thermodynamics only to the extent of associating with each intrinsic quantity of energy an additional amount of potential gravitational energy. In this way an expression is obtained for increase in equilibrium temperature with decrease in gravitational potential which, however, could in any case only be correct as a first approximation in a weak gravitational field. A discussion of the uncertainties and lack of rigor of this preliminary treatment is then given and the necessity pointed out for a rigorous treatment based on the principles of general relativity.
A rigorous relativistic treatment is then undertaken using the extension of thermodynamics to general relativity previously presented by the author. The system to be treated is taken as a static spherical distribution of perfect fluid which has come to gravitational and thermodynamic equilibrium. The principles of relativistic mechanics are first applied to such a system in order to obtain results needed in the later work. And it is then shown that these mechanical principles themselves are sufficient to determine the temperature distribution as a function of potential in the simple case of black-body radiation. The principles of relativistic thermodynamics are then applied to this same case of pure black-body radiation and the same expression for temperature as a function of potential obtained by the thermodynamic as by the mechanical treatment. This may be regarded as giving some measure of check on the validity of the proposed relativistic thermodynamics.
Following this, a thermodynamic treatment is given for the temperature distribution in the more general case of matter and radiation and a result found which harmonizes with that for radiation alone. A treatment is then given to the distribution of a perfect monatomic gas in a gravitational field both on the assumption that the total number of atoms must remain constant and on the assumption of the ready interconvertibility of matter and radiation. In the latter case the same dependence of concentration on temperature is obtained as was found by Stern and by the author for the case of flat space-time.
Using a system of coordinates such that the line element for the sphere of fluid takes the form
ds2=3D-eu(dr2+r2d=CE=B82+r2sin2=CE=B8d=CF=862)+e=CE=BDdt2 the general resul= t for the relation between gravitational potential and equilibrium temperature T0 as measured by a local observer in proper coordinates can be given by the equation d lnT0/dr=3D-1/2d=CE=BD/dr
This equation reduces in the case of a weak field to that obtained by the preliminary non-rigorous treatment, and gives a very small change of temperature with position in fields of ordinary intensity. The result, however, is one of great theoretical interest, since constant temperature throughout any system which has come to thermal equilibrium has hitherto been regarded as an inescapable thermodynamic conclusion. It is also not out of the question that the effect might sometime be of experimental or observational importance.
=C2=A91930 The American Physical Society
Doug wrote:
Reducible to each individual moving particle's mass going up a skosh due to its velocity?
What is the actual peak (between collisions) velocity of, say, a molecule in some given solid at some given temp?
Dave
I bet it has more to do with the washer and valve seat expanding than anything
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