Is it true?
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Chris Hafey wrote: There is no such thing as a energy transfer "momentum". It has to do with the movement of individual molecules/atoms. -:suss:Matt Newman / Windows XP Activist:suss: -Sonork ID: 100.11179
01001001 00100000 01010000 01100001 01100100 00100000 01001101 01111001 00100000 01010000 01101111 01110011 01110100 00100000 01000011 01101111 01110101 01101110 01110100Uhh the movement is directly related to the temperature. pv=nrt right? Chris
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I have zero experience in this subject, but did find this article on Everything2 that presents a plausible explanation for why cold water boils faster. It would seem to indicate that the reverse is not true. --------_**
When will I realize that this skin I'm in Hey, it isn't mine And when will the kill be too much meat for me to hide on...
**_
-- Blind Melon, Skinned
I think they made a mistake, Years ago buckets were made out of WOOD !! Thus the cooling was more via evapouration. If you ever bother to check Francis Bacon's observations in the 1700's he confirms this. Regardz Colin J Davies
Sonork ID 100.9197:Colin
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brian1415 wrote: does anybody know if it is true? I would think yes because I know for a fact that hot water freezes faster than cold water so in theory the invers should be true. -:suss:Matt Newman / Windows XP Activist:suss: -Sonork ID: 100.11179
01001001 00100000 01010000 01100001 01100100 00100000 01001101 01111001 00100000 01010000 01101111 01110011 01110100 00100000 01000011 01101111 01110101 01101110 01110100Matt, BTW: boiling water looses its oxygen so when you freeze it, its more solid and clear with less bubbles etc. Regardz Colin J Davies
Sonork ID 100.9197:Colin
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I know this has nothing to do with programming, but this is the lounge so i will ask it anyway! ;P Erliar today I was getting ready to boil some water for my dinner when my mother told me that cold water begins to boil sooner then warm/hot water... I am semi-scepticle of this, does anybody know if it is true?:confused:
Ok, you guys are starting to make me think I was wrong about the IQ thing, for God's sake. No, water boils when it hits 100C, period, and cold water takes longer to get there than hot water does assuming you're applying the same # joules to each sample. This is assuming of course that you're not actually observing the water in either container as it reaches the boiling point, because as everyone knows: A watched pot never boils. :-D David http://www.dundas.com
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Ok, you guys are starting to make me think I was wrong about the IQ thing, for God's sake. No, water boils when it hits 100C, period, and cold water takes longer to get there than hot water does assuming you're applying the same # joules to each sample. This is assuming of course that you're not actually observing the water in either container as it reaches the boiling point, because as everyone knows: A watched pot never boils. :-D David http://www.dundas.com
David Cunningham wrote: No, water boils when it hits 100C, period, and cold water takes longer to get there than hot water does assuming you're applying the same # joules to each sample. Gosh, it boils at just under 97 here and I'm at a beach. So are you seriously suggesting the opposite always holds true, David. eg cold water doesn't freeze faster ? Regardz Colin J Davies
Sonork ID 100.9197:Colin
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I know this has nothing to do with programming, but this is the lounge so i will ask it anyway! ;P Erliar today I was getting ready to boil some water for my dinner when my mother told me that cold water begins to boil sooner then warm/hot water... I am semi-scepticle of this, does anybody know if it is true?:confused:
Actually, hot water will freeze a bit faster than cold water when both are placed in very cold temperatures due to the lattice structure of water when it is frozen. When water freezes, the water(ice) expands due to the molecules forming a cubic lattice structure. The molecules are farther apart when water is frozen versus when it is a cool liquid. Obviously, when the water is warm, the molecules are farther apart than when the water is cold. Therefore, when water is hot and it molecules are father apart, it is easier for the water to create the cubic lattice structure when being frozen, versus cold water. Note: This isn't true for all possible water temps, only for the temps where the molecule expansion is similiar to the molecular distance between molecules of ice. Kind regards, Tim
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David Cunningham wrote: No, water boils when it hits 100C, period, and cold water takes longer to get there than hot water does assuming you're applying the same # joules to each sample. Gosh, it boils at just under 97 here and I'm at a beach. So are you seriously suggesting the opposite always holds true, David. eg cold water doesn't freeze faster ? Regardz Colin J Davies
Sonork ID 100.9197:Colin
More about me :-)
He forgot to mention that his values are correct assuming the barometric pressure is 1 atmosphere. :) Kind regards, Tim
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brian1415 wrote: does anybody know if it is true? I would think yes because I know for a fact that hot water freezes faster than cold water so in theory the invers should be true. -:suss:Matt Newman / Windows XP Activist:suss: -Sonork ID: 100.11179
01001001 00100000 01010000 01100001 01100100 00100000 01001101 01111001 00100000 01010000 01101111 01110011 01110100 00100000 01000011 01101111 01110101 01101110 01110100 -
I know this has nothing to do with programming, but this is the lounge so i will ask it anyway! ;P Erliar today I was getting ready to boil some water for my dinner when my mother told me that cold water begins to boil sooner then warm/hot water... I am semi-scepticle of this, does anybody know if it is true?:confused:
I've heard that "old wives tale" before but in a different way, which makes it more understandable.... I think what your mother is saying is not quite correct though... This is how it goes: If you have a cup of hot coffee (or other beverage, coffee is just an example here :)) and you want to pour some cold milk into it (or other mixer) and the phone rings. You don't want your coffee to get cold, so do you a) Pour the milk in before the phone call, or b) after the phone call. The answer is a) This is because, when you pour the milk in, it immediately lowers the temperature of the coffee, if left to sit there, he coffee temperature will drop exponentially (as a function of the difference between the coffee temp and the surrounding air) So assume that the milk will instantly lower the temp by 20 degrees, if you put it in straight away, the coffee is 20 degrees cooler and will cool during the phone call at a rate proportional to the cooler temperature. If you leave the coffee sitting there, it will cool at a faster rate due to the higher temperature difference, and then when you put the milk in, it lowers it another 20 desgrees, which will therefore be cooler than the coffee with the milk poured in beforethe phone call.... That's probably too long winded and hard to follow, and it's over simplified, but I think it can be applied in the reverse manner, hot milk added to cold coffee... But I failed thermal physics the first time round, so don't listen to me :);)
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Actually, hot water will freeze a bit faster than cold water when both are placed in very cold temperatures due to the lattice structure of water when it is frozen. When water freezes, the water(ice) expands due to the molecules forming a cubic lattice structure. The molecules are farther apart when water is frozen versus when it is a cool liquid. Obviously, when the water is warm, the molecules are farther apart than when the water is cold. Therefore, when water is hot and it molecules are father apart, it is easier for the water to create the cubic lattice structure when being frozen, versus cold water. Note: This isn't true for all possible water temps, only for the temps where the molecule expansion is similiar to the molecular distance between molecules of ice. Kind regards, Tim
Well explained Tim, I didn't want to get to technical here in the lounge, but I think most people have never heard of the Mpemba effect and stuff like that. Water is not a good typical liquid to use for any reference to what a liquid is, as it has so many known anomalies. Its amazing how much research has gone into this one little field and there are still questions to be answered about waters properties. Regardz Colin J Davies
Sonork ID 100.9197:Colin
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He forgot to mention that his values are correct assuming the barometric pressure is 1 atmosphere. :) Kind regards, Tim
Ok, :-) Here is another factor check how waters viscosity changes with temperature, it is by no means uniform and has a spurt at around 30+ C, I don't think any successful explanation for this has ever been put forward. (must remeber the pressure of course) Something else that alters the equations with water is the non-compressability it almost has. When you heat it the air will expand and the water will almost remain the same. BTW: There are more solid states of Ice than there are carbon, (Its just they all look the same to casual observation) Regardz Colin J Davies
Sonork ID 100.9197:Colin
More about me :-)
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Actually, hot water will freeze a bit faster than cold water when both are placed in very cold temperatures due to the lattice structure of water when it is frozen. When water freezes, the water(ice) expands due to the molecules forming a cubic lattice structure. The molecules are farther apart when water is frozen versus when it is a cool liquid. Obviously, when the water is warm, the molecules are farther apart than when the water is cold. Therefore, when water is hot and it molecules are father apart, it is easier for the water to create the cubic lattice structure when being frozen, versus cold water. Note: This isn't true for all possible water temps, only for the temps where the molecule expansion is similiar to the molecular distance between molecules of ice. Kind regards, Tim
If you start with hot water and apply the freezing process, then you get cold water on the way to getting ice. Thus the time taken for hot to ice equals time of hot to cold plus time of cold to ice. The only possible way that freezing hot water could take less time than freezing cold water is if the cold to ice step takes less time if the water was previously hot, i.e., the characteristics of water depend on its history rather than just on its current temperature. I don't know enough physics to comment confidently on this, but I doubt it. John Carson
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If you start with hot water and apply the freezing process, then you get cold water on the way to getting ice. Thus the time taken for hot to ice equals time of hot to cold plus time of cold to ice. The only possible way that freezing hot water could take less time than freezing cold water is if the cold to ice step takes less time if the water was previously hot, i.e., the characteristics of water depend on its history rather than just on its current temperature. I don't know enough physics to comment confidently on this, but I doubt it. John Carson
I don't wanna get to scientific about it, unless you force me. :-) But as Matt said in a thread above its a bit like momentum. Please remember cold water has air inside it as well. One common result of this is cooking with microwaves, after you take the food out of the microwave it continues to cook. Check a microwave cookbook about this if you want. :-) Regardz Colin J Davies
Sonork ID 100.9197:Colin
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I don't wanna get to scientific about it, unless you force me. :-) But as Matt said in a thread above its a bit like momentum. Please remember cold water has air inside it as well. One common result of this is cooking with microwaves, after you take the food out of the microwave it continues to cook. Check a microwave cookbook about this if you want. :-) Regardz Colin J Davies
Sonork ID 100.9197:Colin
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Colin Davies wrote: Please remember cold water has air inside it as well. But does it have a different amount if it used to be hot? If not, then the hot to ice transition includes a cold to ice transition that is identical to the cold to ice transition that you get if you start with cold water. Colin Davies wrote: One common result of this is cooking with microwaves, after you take the food out of the microwave it continues to cook. That is because it is still hot, not because it is getting hotter. John Carson
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Matt, BTW: boiling water looses its oxygen so when you freeze it, its more solid and clear with less bubbles etc. Regardz Colin J Davies
Sonork ID 100.9197:Colin
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****Colin Davies wrote: BTW: boiling water looses its oxygen so when you freeze it, its more solid and clear with less bubbles etc. Yes and this is also a very good way to get back at a glass container that you are mad at. -Jack To an optimist the glass is half full. To a pessimist the glass is half empty. To a programmer the glass is twice as big as it needs to be.
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Colin Davies wrote: Please remember cold water has air inside it as well. But does it have a different amount if it used to be hot? If not, then the hot to ice transition includes a cold to ice transition that is identical to the cold to ice transition that you get if you start with cold water. Colin Davies wrote: One common result of this is cooking with microwaves, after you take the food out of the microwave it continues to cook. That is because it is still hot, not because it is getting hotter. John Carson
I think we'll only be able to disagree, And I agree that this does not make common sense, nor is it simple logic unfortunatly. Still many of the physical properties of water are not understood by science, which means my argument will dry up somewhere, as I won't be able to explain it, however experimental evidence can prove the assertion. Regardz Colin J Davies
Sonork ID 100.9197:Colin
More about me :-)
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I think we'll only be able to disagree, And I agree that this does not make common sense, nor is it simple logic unfortunatly. Still many of the physical properties of water are not understood by science, which means my argument will dry up somewhere, as I won't be able to explain it, however experimental evidence can prove the assertion. Regardz Colin J Davies
Sonork ID 100.9197:Colin
More about me :-)
I did a quick Google search. Apparently, there are ways in which cold water that used to be hot can differ from water that has been cold from the start. The most important is that more of the water that used to be hot will have evaporated. Thus a smaller volume needs to be frozen (assuming that, in comparing hot to ice and cold to ice, we start with the same initial volume of hot and cold water). Whether a given initial volume of hot water will actually freeze more quickly than a given initial volume of cold water depends on the temperature differences and various other details. It is not a universal result either way. John Carson
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Uhh the movement is directly related to the temperature. pv=nrt right? Chris
Only in a closed system at STP.
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I did a quick Google search. Apparently, there are ways in which cold water that used to be hot can differ from water that has been cold from the start. The most important is that more of the water that used to be hot will have evaporated. Thus a smaller volume needs to be frozen (assuming that, in comparing hot to ice and cold to ice, we start with the same initial volume of hot and cold water). Whether a given initial volume of hot water will actually freeze more quickly than a given initial volume of cold water depends on the temperature differences and various other details. It is not a universal result either way. John Carson
Amazing how such simple stuff can cause this confusion. Here is a link I just posted in the soapbox http://www.sbu.ac.uk/water/explan.html We must be wary also that information that we find on the web is well founded. :-) Best wishes ! Regardz Colin J Davies
Sonork ID 100.9197:Colin
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I know this has nothing to do with programming, but this is the lounge so i will ask it anyway! ;P Erliar today I was getting ready to boil some water for my dinner when my mother told me that cold water begins to boil sooner then warm/hot water... I am semi-scepticle of this, does anybody know if it is true?:confused:
One thing bothers me about this: You don't cook with water from the hot tap do you? Arrgh! If you can't see anything wrong with this, then consider that in most houses (unless they have some kind of instant wanter heater) that your hot water will be sat around in some kind of storage tank somewhere in your house, whereas the cold water will come directly from the pipes. My Dad's an architect, and he's told me that it's fairly common to find dead pigeons/rats/etc floating in hot water tanks. X| So I'd rather wait the extra minute for the water to boil (assuming it is faster to boil water from the hot tap) -- Help me! I'm turning into a grapefruit!