| User | Comment |
|---|
they   | | posted 17-Feb-2001 5:12pm |
I wish I hadn't read the explanation before I made my guess... |
| Enheduanna | | posted 17-Feb-2001 5:23pm |
It seems to me that according to the laws of physics, the hot water should boil faster. But I'm really curious as to the argument for cold water being faster. |
| juliw | | posted 17-Feb-2001 7:50pm |
I don 't know, but I have a really disgusting image concerning how the plumber found out |
| smurf |
I dunno the answer, but apparently in some cases hot water can FREEZE faster than COLD water, so it wouldn't surprise me if the opposite were true! When cold H2O freezes, it freezes first on the top layer of H2O. When hot H2O freezes, it starts around the edges and at the bottom of the container. This allows for massive "cooling off" to take place off the top of the hot H2O. It's all about relativity and stuff .. which I don't really understand, so I'll shut up now!!  |
| hildagard | | posted 17-Feb-2001 9:19pm |
I never heard about this... it's probably because I don't enter kitchen. I mean maybe I would, if i knew where it is. No, I don't live in a palace, but I just keep as far as I can away from kitchen. |
| AliCat13 | | posted 17-Feb-2001 11:46pm |
My science teachers have told me that cold water does freeze faster than colder water. I wouldn't doubt it one bit. It seems kind of odd though if you really think about it. |
Strider   | | (reply to smurf) posted 18-Feb-2001 12:33am |
Thats why when they flood a hockey rink with a |
| Strider | | (reply to smurf) posted 18-Feb-2001 12:35am |
That's why when they flood a hockey rink with a |
| smurf | | (reply to Strider) posted 18-Feb-2001 1:22am |
???????? |
| ASexyBabe | | posted 18-Feb-2001 2:12am |
I think it has something to do with the shock to the molecules when there is a huge sudden temperature change. |
Kristal_Rose  | | posted 18-Feb-2001 3:01am |
Oh brother. Boiling point is a function of temperature and pressure. 212 F is boiling at sea level, the closer the better. I was just boiling a cork out of a bottle when I remembered that the moment that blood wine colored water uncaps it will be at boiling to, all at once, 1cc water = 1500cc steam, big mess. I adapted stategies.
Why did you even write this survey? Judging by your terminology, you know the answer. |
| Kristal_Rose |
Plumbers are not even required to take a single physics class as far as I know. |
| Enheduanna |
I don't know the answer. That's why I asked. I'm inclined towards hot water, but the fact that two people have told me otherwise, and that other people have heard that, too, has made me curious.
Maybe I'll try doing a little experiment. |
| Enheduanna | | posted 18-Feb-2001 11:33am |
OK, I just boiled two cups of hot water in one pot and two cups of cold water in an identical pot. I put them both on the burner at the same time, and the pot of hot water boiled first, by about 20 seconds. Which also proves that a watched pot, whether filled with hot or cold water, will boil. |
| ASexyBabe |
try freezing hot water it freezes faster. |
| Enheduanna | | (reply to ASexyBabe) posted 18-Feb-2001 12:23pm |
I was thinking I'd try it, but I can't really monitor it to check which one freezes faster. |
| Jemmy | | posted 18-Feb-2001 1:22pm |
You'd think hot water would boil faster...I mean, it gets hot anyway before it boils...I don't know. It makes my head hurt. |
| ASexyBabe |
Well I am sure you could pretty easily open the freezer every minute or two and examine each one. How long could it possibly take for water to freeze? I would try it but I only have 1 ice cube tray. |
| mandy | | posted 18-Feb-2001 2:51pm |
*shrugs* |
| johnthomasreed | | posted 18-Feb-2001 3:35pm |
It seems that the laws of thermodynamics would require hot water to boil first. |
| cody | | posted 18-Feb-2001 4:25pm |
If you don't know it is not worth trying to explain it. The hotter water will boil faster [certain cases which are rare, complex, and therefore irrelevant aside], this can be concluded both by reason and logic alone, or by a simple experiment. The man who said this represents all I hate about human beings. I hate stupid people. |
| cody | | posted 18-Feb-2001 4:33pm |
As far as the freezing, same [bull]crap, new scenery. Cold water will freeze more quickly than hot water, don't believe me then try it. Once again, in CERTAIN, rare, complex cases, the opposite may be true, but under normal conditions, the cold water will freeze faster.
The same idiotic argument has been made that cold water evaporates faster... people just need to buy a frigging physics book, forcibly remove their heads from their asses, and use a little bit of common sense, you know?
Now please, no one come back to me detailing all of the reasons why I am wrong, because you will merely be citing an example of what I just said, which is that IN CERTAIN CASES, yeah, sure, weird crap happens. IT is weird because it is NOT the way it usually works.
If people are gullible and stupid enough to believe this, it offers a good explanation as to why monotheism is still popular. |
| natsim | | posted 18-Feb-2001 5:13pm |
It depends if you're talking about the rate at which the water boils, or the time it takes to reach boiling point, doesn't it?
If I remember correctly, the rate at which cold water gets to boiling point is faster than the rate at which hot water gets there (it's probably a millidegree per millisecond difference!). I can't remember all the details on it though, so I could be totally wrong. |
| Enheduanna | | (reply to natsim) posted 18-Feb-2001 8:37pm |
But once the hot and cold water reach boiling, they're both at about 212 F, so of course they'd be boiling at the same rate, right?!
I meant the time it takes for them to reach boiling. |
| natsim |
Of course they boil at the same rate... I meant the rate at which they approach boiling point. Makes very little sense to me...
|
| Strider | | (reply to smurf) posted 18-Feb-2001 11:38pm |
Sorry I was trying to use the word Zamboni too link to http://zamboni.com/ in case you (or any one else) didn't know what it is. As you (and others) may or may not know a Zamboni uses hot water as in freezes faster. |
| cody | | (reply to Strider) posted 19-Feb-2001 12:08am |
Purely ridiculous. I do not know whether the machine uses hot water or not, although I must say that if it does, it is not for the reason you stated.
Assuming it does, the reason likely has more to do with the dynamics of the ice that forms. Generally, the hot water would provide for a smoother surface due to its heightened abillity to flow to lower regions before freezing. As far as differences in rate at which a boiling point is approached, antism is SORT OF correct. At higher temperaturees, more energy is LoST to evaporation, therefore, it is the tendency of the water to increase in temperature more degrees per second at a lower temp. HOWEVER, this is, merely a factor which is caused by the PRACTICLE applications of boiling water, and, under proper conditions (a closed system) this effect would not occur. OF course, once it reached higher temperatures, this effect would go away.
In order for water to boil it must reach 100 degrees celsius normal temp. Assume, for the hell of it, a pot of 90 degree water will take x minutes to boil. A pot of 80 degree water in order to boil, must FIRST be heated to 90 degrees, and then for an additional x minutes (the amount of time it takes for a 90 degree pot of water to boil, because it NOW IS a 90 degree pot). Even if it only takes 1/100000 of a minute for the water to go from 80 degrees to 90, total boiling time will amount to 1/100000+x, which is, necessarily, greater than x. |
| Kristal_Rose | | posted 19-Feb-2001 1:58am |
Zamboni - The hot water can melt and repair the previously scratched up surface. Also hot water may make certain the machine itself does not freeze shut. Rumor has it that hot water will make glassier ice cubes in your home freezer.
Cody said it; 80 c water will need to heat to 90 then 100. 90 c water need only heat to 100.
To use a car analogy, if two studebakers wish to reach 100 mph, the one already doing 90 will get there faster than the one doing 35, but like cody said, you can go from 35 to 45 faster than you can go from 90 to 100.
cody: why are we wasting our time? |
| Zang | | posted 19-Feb-2001 9:47am |
I studied thermodynamics in trade school. (Boilers and Heating systems) Hot water boils faster. I can't find my text book, it must be in the storage locker. Basically, it comes down to transfer of heat. In order to make the water boil, you have to get it up to 100 degrees C. If it is already hot, obviously it will take less time to do that. |
| jkiehart | | posted 20-Feb-2001 11:56am |
Both the same!
|
| arj | | posted 20-Feb-2001 1:06pm |
Cold water doesn't boil. At sea level, only hot water at about 100 degrees C boil. |
| nasale | | posted 25-Feb-2001 2:33pm |
I've always thought that hot water boiled faster because it's closer to the boiling point.Common sense, no? |
| Violet | | posted 27-Feb-2001 4:26pm |
I had never heard of this, so I did some research. It seems that cold water does not boil faster: "Cold water does not boil faster than hot water. The rate of heating of a liquid depends on the magnitude of the temperature difference between the liquid and its surroundings (the flame on the stove, for instance). As a result, cold water will be absorbing heat faster while it is still cold; once it gets up to the temperature of hot water, the heating rate slows down and from there it takes just as long to bring it to a boil as the water that was hot to begin with. Because it takes cold water some time to reach the temperature of hot water, cold water clearly takes longer to boil than hot water does. There may be some psychological effect at play; cold water starts boiling sooner than one might expect because of the aforementioned greater heat absorption rate when water is colder." < http://www.sciam.com/askexpert/physics/physics21.html> ""The same sort of thing happens in reverse in the water kettle. We still have to worry about a heat transfer coefficient between the water and the bottom of the kettle, and there is now a larger temperature difference between the cold water and the bottom of the kettle than between the hot water and the kettle. In this case, the cold water will heat at a faster rate, but the hot water manages to get to the boiling point sooner than the initially cold water." < http://www.swri.org/10light/freeze.htm> |
| autumnlight |
hot water |
| SuperCow |
Simple physics. Especially since, if you try it, you will notice that cold water becomes hot water before it boils. So you need to add the time of going from cold to hot to the mix.
In a hot water heater, on the other hand, it is possible that the thermostat will keep the internal heater going at a different rate, and cause it to be actually heating at a different rate, perhaps causing that particular device under specific circumstances to make parts of the water get to boiling faster, than if the whole tank was hot water to begin with. |
| teenage_misfit | | posted 23-Mar-2001 10:38pm |
But my science teacher says it's healthier to cook things in cold water even if it calls for warm water. |
