hot water pipe frozen

[Baroness Benachi]

Read this

[Joseph Meehan]

Conclusion: "With the Mpemba Effect, warm water can freeze faster than cold water, under certain conditions. Evaporation, conduction, convection and dissolved gases are possible reasons the effect works. You may have to try different configurations to verify this effect."

In the case of the pipe, Evaporation, conduction (assuming the same type and size of pipe) are not factors, so only dissolved gases remain.

As I recall my college physics, the effect of dissolved gases was very small. While it may account for freezing first, it is unlikely to be more than a few minutes difference.

In addition since hot water pipes tend to build up deposits faster than cold, the conduction would be less in the hot water pipe (may be partly offset by the reduced volume of water, which may be offset by the greater insulation provided by the deposits.

I might add that I doubt if any great amount of dissolved gases are released at the temperatures and pressures in a hot water heater. You will note that at times when you fill a glass with hot water, it appears cloudy and then clears. That is gases being released because the water is now under less pressure. So in the pipe the gases are still dissolved.

So lets get enclosed containers filled with various samples of water (different mineral content) some heated to 120º and some not, then placed in a cold environment, careful to provide the same potential for conduction for each and see what happens.

Some quick, incomplete research turned up the fact that at least some experiments showed no, little or conflicting results at trying to measure the dissolved gas effect and apparently no mathematical formula exist.

So while there may be some potential theories, I doubt if you will find any that work under the conditions indicated (hot water pipe freezing when the cold water pipe does not) related to the temperature of the water.

[Mark]

No it isn't a myth. You and all the other theoretical geniuses here should try and do a google search for Mpemba Effect.

[j j]

which, as it has already been explained here, does not apply to a pipe.

[Trent©]

You probably didn't use the hot water...hence, you didn't replace the water that was being cooled in the hot water pipe with warm water. The hot water just sat there...was cooled...and then finally froze.

You should run both the hot and the cold at a small trickle during really cold weather.

Objects have ambient heat in them. The ambient heat has finally all been used up.

Same way that just a dusting of snow will melt at the beginning of the season...but will stick during the middle of Winter.

Have a nice week...

Trent

If the cheese isn't yours...its Nacho cheese, man!

[Trent©]

No. Copper...or any container...will only crack if it is a seal container...and if the force of the freezing water is greater than the strength of the container.

Maybe.

Have a nice week...

Trent

If the cheese isn't yours...its Nacho cheese, man!

[MLD]

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