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  #1  
Old 05-13-2006, 12:48 PM
RockoSoBe RockoSoBe is offline
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Hot water makes ice cubes freeze quicker?

Someone please confirm that this is false so I can get my friend to believe it!
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  #2  
Old 05-13-2006, 01:00 PM
rwjefferson rwjefferson is offline
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My understanding is that the hot water evaporates quickly in the dry air of the freezer. That leaves a smaller amount of water that freezes more quickly. You can get the same results even faster results if you start with less cold water.

rwj
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  #3  
Old 05-13-2006, 01:07 PM
mhendo mhendo is offline
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Quote:
Originally Posted by rwjefferson
My understanding is that the hot water evaporates quickly in the dry air of the freezer. That leaves a smaller amount of water that freezes more quickly. You can get the same results even faster results if you start with less cold water.

rwj
But according to Cecil (who cites a Scientific American article), this is really only an issue at near-boiling temperatures.

For regular hot (tap) water and cold (tap) water, the cold will freeze considerably more quickly.
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  #4  
Old 05-13-2006, 01:21 PM
RockoSoBe RockoSoBe is offline
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Quote:
Originally Posted by mhendo
But according to Cecil (who cites a Scientific American article), this is really only an issue at near-boiling temperatures.

For regular hot (tap) water and cold (tap) water, the cold will freeze considerably more quickly.
Sorry for the duplicate post. It's an old wives tale.
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  #5  
Old 05-13-2006, 01:57 PM
TimeWinder TimeWinder is offline
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First of all, it's not true that hot water freezes faster than cold water -- as others have pointed out. Ignoring miniscule evaporation changes, at some point the hot water will become the same temperature as the cold water started at, and this won't take zero time.

But I have to ask: why not just do the experiment? It's not like this is complicated science that requires a multimillion-dollar lab or require a statistician to interpret the results. You could have your answer in an hour; three or four if you want to completely eliminate concerns about conditions like position of the water in the freezer.
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  #6  
Old 05-13-2006, 03:20 PM
Sailboat Sailboat is offline
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There IS a reason some people make ice cubes from hot water. It has nothing to do with them freezing faster, however.

Hot water holds less dissolved oxygen. Ice cubes made from hot water are clear, lacking the whiteness from internal bubbles.

Restaurants and caterers will sometimes use warm or hot water to make "prettier" ice cubes. Perhaps this contributes to the persistence of the belief?

Sailboat
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  #7  
Old 05-13-2006, 03:46 PM
bouv bouv is offline
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Quote:
Originally Posted by Sailboat
Hot water holds less dissolved oxygen. Ice cubes made from hot water are clear, lacking the whiteness from internal bubbles.
Here's where you lose me. At every faucet that I have noticed, the hot water seems to have more "air" in it than cold. The hot water has always been cloudy from many more small air bubbles than the cold water.
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  #8  
Old 05-13-2006, 03:50 PM
spingears spingears is offline
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Quote:
Originally Posted by Sailboat
There IS a reason some people make ice cubes from hot water. It has nothing to do with them freezing faster, however.
Hot water holds less dissolved oxygen. Ice cubes made from hot water are clear, lacking the whiteness from internal bubbles.
Restaurants and caterers will sometimes use warm or hot water to make "prettier" ice cubes. Perhaps this contributes to the persistence of the belief?Sailboat
Water that has been boiled and cooled to room or tap water temperature will freeze faster!
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  #9  
Old 05-13-2006, 03:54 PM
spingears spingears is offline
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Quote:
Originally Posted by RockoSoBe
Someone please confirm that this is false so I can get my friend to believe it!
Water that has been boiled and cooled to tap water temperature will freeze faster/sooner.
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  #10  
Old 05-13-2006, 05:30 PM
LawMonkey LawMonkey is offline
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Originally Posted by spingears
Water that has been boiled and cooled to tap water temperature will freeze faster/sooner.
Uhh... care to explain this one? Water that has been boiled and cooled to room temperature, except for possibly having less dissolved gasses in it, is AFAIK exactly the same as plain ol' water fresh from the tap.

Quote:
Originally Posted by Sailboat
Hot water holds less dissolved oxygen. Ice cubes made from hot water are clear, lacking the whiteness from internal bubbles.
My understanding is that it's not that the hw has less dissolved gasses--hot water is going to allow more gasses to disolve, not less--but that it will tend to freeze more slowly, thus giving the bubbles a chance to escape, leading to a clearer, 'pretty' ice cube.
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  #11  
Old 05-14-2006, 07:56 AM
FlyingRamenMonster FlyingRamenMonster is offline
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Originally Posted by bouv
Here's where you lose me. At every faucet that I have noticed, the hot water seems to have more "air" in it than cold. The hot water has always been cloudy from many more small air bubbles than the cold water.
It's probably just a peculiarity of the plumbing, that water from the heater doesn't completely fill the pipes or something. The solubility of gases in liquid decreases with increasing temperature so hot water has less dissolved air in it than cold. You can see this for yourself by boiling a pot of water and watching air bubbles materialise at the bottom from what seems like nowhere.
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  #12  
Old 05-14-2006, 04:21 PM
chorpler chorpler is offline
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Quote:
Originally Posted by Lemur Catta
Uhh... care to explain this one? Water that has been boiled and cooled to room temperature, except for possibly having less dissolved gasses in it, is AFAIK exactly the same as plain ol' water fresh from the tap.
It's the "less dissolved gases" that lets it boil faster, IIRC.


Quote:
My understanding is that it's not that the hw has less dissolved gasses--hot water is going to allow more gasses to disolve, not less--but that it will tend to freeze more slowly, thus giving the bubbles a chance to escape, leading to a clearer, 'pretty' ice cube.
Actually, hot water has a lower capacity for dissolved gases than cold water. The oceans have a lot more life in the very cold places like the arctic than they do in the equatorial regions, because the water has lots more oxygen dissolved in it.

If you've ever compared a carbonated drink -- a can of Pepsi, say -- at room temperature to one that's just above freezing, you'll see this in action. The ice-cold Pepsi feels almost like tangy fizzy water, while the warm Pepsi is a huge mess of foam and bubbles immediately, to the point that it's harder to drink since it's like drinking soap suds. Not surprisingly, most people prefer their carbonated beverages cold.
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  #13  
Old 05-14-2006, 04:24 PM
alterego alterego is offline
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This is my fav explanation: http://math.ucr.edu/home/baez/physic...hot_water.html
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  #14  
Old 05-14-2006, 05:54 PM
roscolbar roscolbar is offline
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Salts, which lower freezing temperature, will precipitae out if water is bolied. Their granularity will assist crystal formation and if FlamingRamenMonster looks real-l close s/he will descry the "air bubbles" masquerading as steam.
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  #15  
Old 05-14-2006, 05:57 PM
GiantRat GiantRat is offline
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Quote:
Originally Posted by Sailboat
There IS a reason some people make ice cubes from hot water. It has nothing to do with them freezing faster, however.

Hot water holds less dissolved oxygen. Ice cubes made from hot water are clear, lacking the whiteness from internal bubbles.

Restaurants and caterers will sometimes use warm or hot water to make "prettier" ice cubes. Perhaps this contributes to the persistence of the belief?

Sailboat
Not such a hot idea to use hot tap water, though. Hot water tends to contain higher concentrations of potentially dangerous minerals and elements that gather as sedimentation in your water heater. At least, that's what a plumber friend told me when I commented about loving to drink shower water. There, I said it. I drink shower water.
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  #16  
Old 05-14-2006, 06:37 PM
Musicat Musicat is online now
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Is the OP asking about pure H2O, as in a laboratory condition, or ice cubes in a consumer fridge that may have other matter dissolved in it and be subject to convection and other confounding factors?

In other words, are we arguing physics or semantics?

FYI: A previous thread exists.

I am assuming we are talking about pure water, in identical amounts, with no confounding factors like convection, movement, light, container differences, etc. -- if not, all bets are off.

If by "faster", you mean the rate of change (slope of a curver or line) is steeper, so that with any two identical samples, the one starting at the higher temp will cool faster (the slope is steeper).

But if by "faster", you mean how long it takes for two samples to lose enough heat to reach temperature X, then there is no way that a hotter starting sample will cool faster than a cooler starting sample.

Consider this: If two identical samples differing only in their initial temperature are cooled by the same amount of heat extraction for each and are started at the same time, at some point in time the originally hotter sample must exactly match the current temp of the originally cooler sample. At that point, unless you postulate that the substance has some kind of memory about past events, they become identical in every way. If the originally hotter one subsequently reaches freezing sooner than the other, something paranormal is going on here.
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  #17  
Old 05-14-2006, 08:50 PM
BoringDad BoringDad is offline
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Quote:
Originally Posted by Musicat
In other words, are we arguing physics or semantics?
I agree that this is critical. The "hot water freezes faster than cold" as generally used by the public is, to my mind, generally a plumbers myth as they propound this "fact" for anything from hot water pipes freezing faster than cold water pipes to ice cubes in a refrigerator.

Quote:
at some point in time the originally hotter sample must exactly match the current temp of the originally cooler sample. At that point, unless you postulate that the substance has some kind of memory about past events, they become identical in every way.
I have always said the same thing, however, alterego's cite did point out that there could be initial starting conditions such that when the average temperature of the hot water had cooled down to the temperature of the starting cool water the originally hot water could have a steep temperature gradient such that some of the water is very cold and some still very hot. In that case, we would not expect it to behave the same as the originally cold water.

So it's back to semantics. As a general statement, cold water freezes before hot water. But like all things in life, there could be exceptional cases where the hot water could freeze faster. (Hot water ice cube trays placed on hard packed snow such that the hot tray melts into the snow and increases heat transfer while the cold sits on top, open containers that have water evaporate off the top and lower the mass of the water while also losing extra heat due to evaporation, funky shaped containers which only have heat loss surfaces at specific areas such that they set up convection currents at certain temperatures, hot water pipes that are used less frequently than cold water pipes, etc.)
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  #18  
Old 05-14-2006, 09:49 PM
FlyingRamenMonster FlyingRamenMonster is offline
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Quote:
Originally Posted by roscolbar
Salts, which lower freezing temperature, will precipitae out if water is bolied. Their granularity will assist crystal formation and if FlamingRamenMonster looks real-l close s/he will descry the "air bubbles" masquerading as steam.
Say what?
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  #19  
Old 05-15-2006, 12:02 AM
RockoSoBe RockoSoBe is offline
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Quote:
Originally Posted by TimeWinder
First of all, it's not true that hot water freezes faster than cold water -- as others have pointed out. Ignoring miniscule evaporation changes, at some point the hot water will become the same temperature as the cold water started at, and this won't take zero time.

But I have to ask: why not just do the experiment? It's not like this is complicated science that requires a multimillion-dollar lab or require a statistician to interpret the results. You could have your answer in an hour; three or four if you want to completely eliminate concerns about conditions like position of the water in the freezer.
Why didn't I do the experiment? I have common sense. I never believed this wives tale
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  #20  
Old 05-15-2006, 07:54 AM
Musicat Musicat is online now
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Quote:
Originally Posted by BoringDad
... there could be initial starting conditions such that when the average temperature of the hot water had cooled down to the temperature of the starting cool water the originally hot water could have a steep temperature gradient such that some of the water is very cold and some still very hot. In that case, we would not expect it to behave the same as the originally cold water.
Please propose a test where, given two samples of pure H2O, at exactly the same temperature, you can tell which one was hotter a few minutes ago from merely testing the samples.

If "some of the water is very cold and some still very hot" then you don't have a uniform sample and you have altered the question to "does hot water cool faster than cold water if non-uniform cooling or convection is allowed?"
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  #21  
Old 05-15-2006, 08:20 AM
Quercus Quercus is online now
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Originally Posted by GiantRat
Not such a hot idea to use hot tap water, though. Hot water tends to contain higher concentrations of potentially dangerous minerals and elements that gather as sedimentation in your water heater. At least, that's what a plumber friend told me when I commented about loving to drink shower water. There, I said it. I drink shower water.
Just one question on this: if the 'dangerous minerals and elements' aren't already in the tap water coming into the water heater, how do they get there? And if they are coming from the tap water, doesn't the fact that there's deposit in the heater mean there is on average less of them in the water leaving the heater than in the cold tap water coming in?

I think this is right up there with 'Hot water freezes faster'. It's just possible that a poorly adjusted hot water heater could have some bacterial growth, but so rare that it's not a general concern. And 'dangerous elements' aren't going to be there any more than anywhere else. Guzzle away in the shower with no fear.
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  #22  
Old 05-15-2006, 08:26 AM
Hari Seldon Hari Seldon is offline
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Ah, all you people with short memories. Mine goes back to the 40s and we had an old-fashioned fridge whose freezer compartment was large enough for two ice cube trays and a couple cans of frozen juice. More to the point, it was not auto-defrost and, especially in the humid summer the freezer compartment was usually heavily encrusted with ice. If you put a tray of hot water in the freezer, it melted down some of the encrustation and froze relatively quickly. There might also have been significant evaporation. A tray of cold water just sat on the ice and froze more slowly.
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  #23  
Old 05-15-2006, 09:42 AM
CookingWithGas CookingWithGas is offline
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Much has been written about this one and it's interesting that despite an authoritative article from Cecil that it is still not settled. A Google search on "hot water freeze faster cold water" gives Cecil's column as the second entry!

Here is the first entry, the best treatment of the subject that I've found.

It is possible to create a situation where hot water will freeze faster but that is because of uncontrolled variables other than temperature.

To those who have pointed out in other threads that the freezer compressor will run more often if a tray of hot water is in the freezer and therefore freeze it faster, I will add that the job of the compressor and thermostat is to keep the temperature of the freezer nearly constant, so this should not make any difference, unless the hot water overwhelms the compressor's ability to cool the freezer, in which case the hot water would freeze more slowly. A better test would be to put two trays outdoors in cold temperatures on the same bare surface (to eliminate the "frost melt" effect).

Time for another entry in the Unofficial FAQs.
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  #24  
Old 05-15-2006, 12:03 PM
KidScruffy KidScruffy is offline
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The best explanation I've heard for this is the "Freezing momentum" explanation. Much like a ball rolling downhill which started on a higher, steeper hill can overtake a ball that started much lower, hot water as it freezes gains freezing momentum - so the water that started at 90 degrees will be cooling at a much faster rate once it hits, say, 30 degrees than will the water that started at 30.

No cite, but it just kind of 'feels right', doesn't it?
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  #25  
Old 05-15-2006, 12:31 PM
CookingWithGas CookingWithGas is offline
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Quote:
Originally Posted by KidScruffy
The best explanation I've heard for this is the "Freezing momentum" explanation. . . .No cite, but it just kind of 'feels right', doesn't it?
Sorry, no basis in fact.

Rolling balls are governed by the force of gravity. A force on a mass results in an acceleration, which is not an analogy for heat loss. If you wanted to really stretch this analogy, you would have to place both balls on the same hill, not one on a steeper hill. And the hill would be a curve with steepness that levels off (my guess would be exponentially but I don't know the formulas for heat loss to ambient air).

Heat loss by convection (i.e., loss of heat by an object to calm air around it) is proportional to the difference in temperature between the object and the surrounding air. The hotter water will lose heat faster at first, but when it cools to the same temperature as the starting temperature of the cooler water, it will lose heat at the same rate as the cooler water started out. This assumes no evaporation from the hotter water, no differences in dissolved gasses or impurities, same container, etc. So the cooler water has a head start that the hotter water can never make up.

There is no such thing as building momentum for heat loss--heat loss can be calculated at a point in time from the parameters at that time without knowing anything about the history of that object's cooling process.

Here's a cite. OTOH a Google search for "freezing momentum" came up with exactly one hit, a highly technical paper entitled, "Colour transparency and scaling properties of nuclear shadowing in deep inelastic scattering" of which I found even the abstract impenetrable but I can tell you they weren't talking about how long it takes for hot water to freeze.
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  #26  
Old 05-15-2006, 12:49 PM
KidScruffy KidScruffy is offline
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Quote:
Originally Posted by CookingWithGas
Sorry, no basis in fact.
Ack, sorry CookingWithGas - I had to choose between being lambasted for joking in GQ, and looking like a dunce*. I think I chose poorly - I don't know much about science, though, so thanks for the informative reply.

Sorry for side-tracking the OP.

--KidScruffy


* I have been known to repeat the 'cooling momentum' theory, and see who will fall for it. So in case you're wondering who is helping spread the ignorance that the SD is fighting...guilty as charged.
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  #27  
Old 05-15-2006, 01:26 PM
CookingWithGas CookingWithGas is offline
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Quote:
Originally Posted by KidScruffy
I had to choose between being lambasted for joking in GQ, and looking like a dunce*. I think I chose poorly
But which one did you choose?

OK, I still don't know which one of us got whooshed. Me 'cuz I missed the joke or you with a theory that doesn't hold up.
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  #28  
Old 05-15-2006, 01:57 PM
KidScruffy KidScruffy is offline
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Quote:
Originally Posted by CookingWithGas
But which one did you choose?

OK, I still don't know which one of us got whooshed. Me 'cuz I missed the joke or you with a theory that doesn't hold up.
It's definitely a joke...sorry for the whoosh.
I was hoping the "it just sort of feels right" logic would give it away, but I guess I'm too little known here to not be taken seriously.

Actually, now that I think about it, it's probably easier for you to believe that I did endorse that theory, and now I'm trying to talk my way out of it. So maybe the last laugh's on me.

--KidScruffy
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  #29  
Old 05-15-2006, 04:30 PM
BoringDad BoringDad is offline
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Quote:
Originally Posted by Musicat
Please propose a test where, given two samples of pure H2O, at exactly the same temperature, you can tell which one was hotter a few minutes ago from merely testing the samples.
I obviously did not make that claim.

Quote:
If "some of the water is very cold and some still very hot" then you don't have a uniform sample and you have altered the question to "does hot water cool faster than cold water if non-uniform cooling or convection is allowed?"
The OP was not so precise as to include or rule out such things, so the question was not altered. As I stated, the blanket statement "Hot water freezes faster" is generally false. But if you press it, it becomes a question of semantics, heat transfer, volume, odd shape, surrounding conditions, etc.
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Old 05-15-2006, 04:36 PM
BoringDad BoringDad is offline
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Quote:
Originally Posted by Musicat
Please propose a test where, given two samples of pure H2O, at exactly the same temperature, you can tell which one was hotter a few minutes ago from merely testing the samples.
I obviously did not make that claim.

Quote:
If "some of the water is very cold and some still very hot" then you don't have a uniform sample and you have altered the question to "does hot water cool faster than cold water if non-uniform cooling or convection is allowed?"
The OP was not so precise as to include or rule out such things, so the question was not altered. As I stated, the blanket statement "Hot water freezes faster" is generally false. But if you press it, it becomes a question of semantics, heat transfer, volume, odd shape, surrounding conditions, etc.
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  #31  
Old 05-15-2006, 06:24 PM
daffyduck daffyduck is offline
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Quote:
Originally Posted by CookingWithGas
To those who have pointed out in other threads that the freezer compressor will run more often if a tray of hot water is in the freezer and therefore freeze it faster, I will add that the job of the compressor and thermostat is to keep the temperature of the freezer nearly constant, so this should not make any difference, unless the hot water overwhelms the compressor's ability to cool the freezer, in which case the hot water would freeze more slowly.
You're forgetting that when the compressor runs, it blows cold air around the freezer compartment which does a much better job of freezing the cubes than stagnant cold air does. I've observed this first hand as I make and consume a lot of ice. Putting trays into a running freezer makes ice much faster than putting them into a not running freezer, even though the temperature of the not running freezer is, by your own definition, colder than the temperature of the running freezer. I always make my ice from water stored in the cold section of the fridge, so the starting temp is always the same, but the time to cubes is much quicker on hot days when the compressor works more often to maintain the temp of the freezer.
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Old 05-16-2006, 11:59 AM
CookingWithGas CookingWithGas is offline
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Quote:
Originally Posted by daffyduck
You're forgetting that when the compressor runs, it blows cold air around the freezer compartment which does a much better job of freezing the cubes than stagnant cold air does.
This is true, and is how a convection oven works. As warm water cools, it is warming the air immediately around it. If that air is calm, a warm envelope is created around the water (neglecting for the moment convection currents). However, if the air is blowing around the warmer air is carried off, refreshing the area near the water. I did not consider the actual movement of the air, just the constant temperature.

Regardless, if you use the "compressor runs more often" argument to prove that hotter water freezes faster, you have created another variable, unless you put both trays in at the same time.
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  #33  
Old 05-16-2006, 12:40 PM
BoringDad BoringDad is offline
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Originally Posted by CookingWithGas
Regardless, if you use the "compressor runs more often" argument to prove that hotter water freezes faster, you have created another variable, unless you put both trays in at the same time.
Definitely true. And not only that, but a freezer does NOT maintain a constant temperatire, it maintains temp within a range of several degrees. So if you force the freezer on, the initial starting temp of the freezer will be several degrees lower than if you did not force the freezer on. Depending on the size of the freezer, the thermal mass in freezer, amount of water, etc the colder freezer conditions could carry through for the duration of the experiment.
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  #34  
Old 05-16-2006, 01:18 PM
solkoe solkoe is offline
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Has anyone considered how hockey ice rinks are cleaned between periods? I believe hot water is used.
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  #35  
Old 05-16-2006, 01:21 PM
solkoe solkoe is offline
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I should have added that I build a hockey rink in my backyard every year. I use hot water whenever possible.
As stated above, there are a lot of variables in this. Certainly the size, shape of the container is a big factor.
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  #36  
Old 05-16-2006, 01:49 PM
CookingWithGas CookingWithGas is offline
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Quote:
Originally Posted by solkoe
Has anyone considered how hockey ice rinks are cleaned between periods? I believe hot water is used.
I believe so based on my observations of the steaming trail left behind the Zamboni. This may not be because it freezes faster, however. If it does freeze faster it's only because a bunch of it evaporates leaving a thinner layer to freeze. You could achieve the same effect by using less water to begin with.

There may be some other benefit to using hot water to melt a little of the existing surface and allow it to refreeze, maybe makes for smoother ice or something, I dunno.
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  #37  
Old 05-16-2006, 01:51 PM
Colibri Colibri is offline
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Quote:
Originally Posted by solkoe
I should have added that I build a hockey rink in my backyard every year. I use hot water whenever possible.
As stated above, there are a lot of variables in this. Certainly the size, shape of the container is a big factor.
What are you saying? You use hot water because you think it freezes faster?

I think that the problem may most simply be stated as, all other factors being equal - identical amounts of water, of the same composition, in identical containers, side by side under identical temperatures - the colder water will undoubtedly freeze first.
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  #38  
Old 05-16-2006, 05:58 PM
Punoqllads Punoqllads is offline
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Quote:
Originally Posted by CookingWithGas
Sorry, no basis in fact.
...well...

It seems reasonable to me to consider convection currents and temperature gradients the equivalents of the "cooling momentum" of a substance.
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  #39  
Old 05-16-2006, 06:06 PM
Punoqllads Punoqllads is offline
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Quote:
Originally Posted by Colibri
I think that the problem may most simply be stated as, all other factors being equal - identical amounts of water, of the same composition, in identical containers, side by side under identical temperatures - the colder water will undoubtedly freeze first.
Sounds reasonable. However, I recommend that you read the article that alterego cited (http://math.ucr.edu/home/baez/physic...hot_water.html) before deciding that "reasonable" equates to "truth". Specifically, the parts (and references) that say that hot water can freeze faster than cold water even after taking into account any influences due to evaporation and dissolved gasses.
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  #40  
Old 05-16-2006, 06:44 PM
lissener lissener is offline
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Quote:
Originally Posted by CookingWithGas
There may be some other benefit to using hot water to melt a little of the existing surface and allow it to refreeze, maybe makes for smoother ice or something, I dunno.
Exactly right.
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  #41  
Old 05-22-2006, 07:55 AM
Musicat Musicat is online now
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Quote:
Originally Posted by BoringDad
Quote:
Originally Posted by Musicat
If "some of the water is very cold and some still very hot" then you don't have a uniform sample and you have altered the question to "does hot water cool faster than cold water if non-uniform cooling or convection is allowed?"
The OP was not so precise as to include or rule out such things, so the question was not altered. As I stated, the blanket statement "Hot water freezes faster" is generally false. But if you press it, it becomes a question of semantics, heat transfer, volume, odd shape, surrounding conditions, etc.
The OP didn't rule out this dialog, either:

Does hot water make ice cubes faster?

Yes. Put a tray of hot water in the freezer and leave a tray of cold water on the kitchen counter. The hot water will always freeze faster.

Unless the fridge is defective or the kitchen counter is in an unheated room in Antarctica.

Quote:
Originally Posted by KidScruffy
The best explanation I've heard for this is the "Freezing momentum" explanation. Much like a ball rolling downhill which started on a higher, steeper hill can overtake a ball that started much lower, hot water as it freezes gains freezing momentum - so the water that started at 90 degrees will be cooling at a much faster rate once it hits, say, 30 degrees than will the water that started at 30.

No cite, but it just kind of 'feels right', doesn't it?
Not to a physics major, it doesn't. See my previous posts:
Quote:
Originally Posted by Musicat
Please propose a test where, given two samples of pure H2O, at exactly the same temperature, you can tell which one was hotter a few minutes ago from merely testing the samples.
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  #42  
Old 05-22-2006, 11:10 AM
CookingWithGas CookingWithGas is offline
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Quote:
Originally Posted by Musicat
Not to a physics major, it doesn't. See my previous posts:
Dude, it was a joke. See previous posts from a week ago.
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  #43  
Old 05-22-2006, 02:47 PM
Musicat Musicat is online now
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Quote:
Originally Posted by CookingWithGas
Dude, it was a joke. See previous posts from a week ago.
In that case, we need a whoosh smiley.
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  #44  
Old 10-27-2013, 02:52 AM
CerebralZombie CerebralZombie is offline
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Quote:
Actually, hot water has a lower capacity for dissolved gases than cold water. The oceans have a lot more life in the very cold places like the arctic than they do in the equatorial regions, because the water has lots more oxygen dissolved in it.
There is more oxygen in the Arctic ocean not because it's cold, it's because the ice there is full of oxygen. Animals were a lot bigger when dinosaurs were around because the oxygen levels were much higher then. After the ice age, tons of the worlds oxygen was frozen.
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  #45  
Old 10-27-2013, 03:39 AM
JBDivmstr JBDivmstr is offline
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Quote:
Originally Posted by CerebralZombie View Post
There is more oxygen in the Arctic ocean not because it's cold, it's because the ice there is full of oxygen. Animals were a lot bigger when dinosaurs were around because the oxygen levels were much higher then. After the ice age, tons of the worlds oxygen was frozen.
Cite?
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  #46  
Old 10-27-2013, 04:06 PM
Cayuga Cayuga is offline
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Quote:
Originally Posted by CerebralZombie View Post
There is more oxygen in the Arctic ocean not because it's cold, it's because the ice there is full of oxygen. Animals were a lot bigger when dinosaurs were around because the oxygen levels were much higher then. After the ice age, tons of the worlds oxygen was frozen.
Best combination of user name and resurrection of zombie thread ever.
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  #47  
Old 10-27-2013, 04:08 PM
Cayuga Cayuga is offline
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For what it's worth, many years ago I filled two identical ice trays, one with hot tap water and one with cold tap water. The cold water froze much more quickly.

The OP is welcome to use me as a cite, if s/he is still around.
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  #48  
Old 10-27-2013, 04:35 PM
clairobscur clairobscur is offline
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Quote:
Originally Posted by Quercus View Post
Just one question on this: if the 'dangerous minerals and elements' aren't already in the tap water coming into the water heater, how do they get there?.
I never heard of "dangerous minerals and elements". However, I've heard about dangerous bacterias that can multiply more readily in hot water, leading to stricter norms (In fact I was talking about this very subject with a friend who is a plumber yesterday).
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  #49  
Old 10-27-2013, 05:16 PM
Der Trihs Der Trihs is offline
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Quote:
Originally Posted by CerebralZombie View Post
There is more oxygen in the Arctic ocean not because it's cold, it's because the ice there is full of oxygen. Animals were a lot bigger when dinosaurs were around because the oxygen levels were much higher then. After the ice age, tons of the worlds oxygen was frozen.
Uh, if the poles were cold enough to freeze oxygen, the rest of the planet would be frozen solid too.
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  #50  
Old 10-31-2013, 02:16 PM
dougrb dougrb is offline
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Doesn't make any sense to me, but....

https://medium.com/editors-picks/d8a2f611e853
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