Heard this at a party over the weekend and argued with the guy for a half hour. His statement was :
“Hot water freezes faster than cold water.”
Was he in fact right ? Or am I in the wrong for debating physics with a drunkard ?
Thanks for the help SD people, you all shine like a candle in the teeming millions ignorant darkness.
“Solos Dios basta” . . . but a little pizza won’t hurt.
The chemistry books say so! It is hard to believe…maybe a Chem E can give details?
Here’s what Cecil Adams has to say on the subject:
Which freezes faster, hot water or cold water?
This could be moved to “Comments on Cecil’s Columns.”
Well, you beat me to the punch Arnold.
I’ll post a quick summary, though. The absolute final and undisputable answer is, “Yes and no.”
It that good enough?
Thanks Arnold,
I did not realize that Unca Cecli would have covered such an pointless topic, but I should have known eh ? In the context of the argument I had, I was right. Yet seeing as I never wish to see that drunk bastard again I suppose it doesn’t matter.
The SD people were on top of it, yet again.
“Solos Dios basta” . . . but a little pizza won’t hurt.
UncleBeer wrote:
Well, it’s more like a big NO with a footnote that you shouldn’t bet any money on the prospect that someone can’t figure a way to make it happen. The two ways I’ve heard are:
If you start with really hot water, the water could basically boil off to a smaller volume, which would freeze faster. But a reasonable assumption would be that you need to end up with the same amount of ice.
If the water is placed in a shallow pan, resting on some freezer frost, it’s possible that the hot water could melt the frost enough to get a larger contact area with the freezer bottom, transferring heat more efficiently. As far as I know, this is conjecture and has never been demonstrated.
Do these allow someone to make a blanket statement that “Hot water freezes faster”?
“Hot water,” no.
“Boiling water,” maybe.
I think it also has to do with how much surface area it has to boil off, and what it is contained in, since a good insulator will not radiate heat outwardly so well as a good conductor.
Final answer: It depends.
Anyone can come up with contrived situations to make something true. But water at 108 degrees F. will take longer to freeze than water at 38 degrees F.
I would assume that if this were not the case, an ice cube would come to a boil faster than the hot water out of the tap.
By the way, that hot water freezes faster seems to be the prevalent belief. I can’t tell you how many times I have heard this. [must control urge to sound like a smarty pants, must control urge to strange dolt.]
<shaking head and wondering why it is that people here persist in posting thoughts for which they have no proof after someone has directed everyone’s attention to a rather complete answer by Uncle Cecil…>
<I have no idea either, Mr. Young. Cecil’s column doesn’t leave much room for debate or disagreement.>
IIRC, Cecil dealt with a related problem a VERY long time ago, in response to a guy who thought his beer would chill faster in the refrigerator than in the freezer. As any serious beer drinker knows, it ain’t so. (I LOVE my freezer! :D)
The situation is different, but the same laws of thermodynamics govern both problems. I think the confusion on the part of some folks stems from the true statement that hot water sheds heat at a faster rate than cold water in the same environment, but that’s simply because the hot water has more heat to shed.
I don’t know why fortune smiles on some and lets the rest go free…
T
A smaller volume of water will freeze faster than a larger volume. See comment “Which freezes faster, hot water or cold water?” above.
Another easy way to answer the question is to draw a graph, with time along the X axis and Temp on the vertical, with warmer on top, cooler on the bottom.
Start with the hot water. It will be high on the left of the chart, and fall as time passes until it hits freezing.
The cooler water’s line will start lower, and eventually fall to the freeeze line.
If the hot water gets to freezing first, it would have to cross the trace of the cooler water, and at that point, the temperatures would be equal.
If the (originally) warmer water continued to fall at a steeper rate, then it would have to have some ‘memory’ of having been hotter in the past.
Does it? No.
When you consider that the hot water would have to reach the same temperature as the cold water on its way to the freezing point it should be obvious that cold water freezes faster. Some numbers that are apropos:
Heat of fusion of water: 335 J/g
Specific heat of water : ~ 4.2 J/g (at near freezing point)
Thus it takes about the same amount of energy transfer to cool the water from 80C to 0C as it does to freeze it after it reaches 0C.
Since heat conduction is proportional to the temperature difference the temperature of the freezer would have to be taken into account as well.
Under controlled conditions the hot water will, of course, take longer to freeze. Under real-life conditions, as others have pointed out, you can probably get the result you want.
Hot water doesn’t freeze at all… Only after it has cooled to the freezing point will the molecules begin to arrange themselves to allow for the crystalline structures that are imperative for ice to form.
However, if you boil water, then let it cool to room temperature before inserting it into the freezer, it will tend to freeze faster than water that was just at room temperature. (This phenominon was explained to us in Chemistry lecture about three years ago) Boiled, then cooled, water will freeze faster because it has had the dissolved gasses removed from it during the boiling process.
The removal of these gasses, I have to assume to be Oxygen, Nitrogen, Carbon Dioxide, etc, is also the reason that VERY hot water will freeze before very hot water, as was brought up in a previous post.
Good thing I’m going to be a science teacher…
you cannot remove Oxygen from water which is H20 wouldn’t be water then anymore would it?
it would just be gas H(superscript2) which would have to be at -372 celsius to freeze=subparticle interia, nothing moves, ie space.
when boiling yes takes out the trace elements but u cannot separate that bond by such basic means, being one of the most stable bonds of all classes Hydrogen bonding…
geesh, and that was just my grade 11 chem class–4 years ago
I am a fire whose flames lick and spit at the boundless sky forever desiring wonderous consummation
-me
You’re going to be science teacher!!!
in the great words of Kilgore,
wow.
hahahahaha
wow.
I am a fire whose flames lick and spit at the boundless sky forever desiring wonderous consummation
-me
Oh come on guys, he said dissolved gasses, and oxygen would be one of them. The oxygen tied up in the water molecules isn’t dissolved.
I am a fire whose flames lick and spit at the boundless sky forever desiring wonderous consummation
-me
can a real chemist please step forward and teach some of these bozos about chem…
breaking H2O is done molecularlly, same as CO2 and H2 and C14(diamonds)
take a class, try high school, grade 11 here in Canada
I am a fire whose flames lick and spit at the boundless sky forever desiring wonderous consummation
-me
Prose, you are wrong. I leave it to you to discover how, since you are obviously unwilling to listen to anyone else. :rolleyes:
If I were to say that today’s tomatoes are an index of the decline of Western man I should be thought a crank but nations do not, I think, ascend on such tomatoes.
–Russell Hoban in Turtle_Diary