Is it true?
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How can this be true? If the volume of water is the same, the cooler water will always take longer. The ammount of time is how long it takes for the cold to equal the warmer water's temperature. There is no such thing as a energy transfer "momentum".
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
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How can this be true? If the volume of water is the same, the cooler water will always take longer. The ammount of time is how long it takes for the cold to equal the warmer water's temperature. There is no such thing as a energy transfer "momentum".
See, that is what I thought but some of these posts are very convincing. :)
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Roger Wright wrote: intitial temperature of the warmer sample, the rate of heat transfer should be the same to the boiling point. I'm not 100% sure how it works but it is kind of like momentum. -: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****Matt Newman wrote: kind of like momentum. Ya think maybe giving the cold water a running start helps? :laugh:
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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:
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...
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-- Blind Melon, Skinned
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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:
brian1415 wrote: I know this has nothing to do with programming, but this is the lounge so i will ask it anyway! Thats the spirit ! brian1415 wrote: 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... First don't argue with your mum, OK ! There is a lot of information you have left out. Is the kettle or appliance already hot ? What material is the kettle made out of ? Is the water highly oxygenated ? etc. These factors will determine the heat transfer coefficients, that have to deal with surface shape, flow textures. For example if the kettle is hot already, the difference will be greater with the cold water and the transference will be initially faster, the air may become movemented quicker in the colder water as well allowing for it to heat faster. The opposite is easier to work out that of freezing water, where you can use Newtons Law of Cooling. But remember not all heat transfered is used and converted to calories. Regardz Colin J Davies
Sonork ID 100.9197:Colin
More about me :-)
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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
More about me :-)
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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
More about me :-)
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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
More about me :-)
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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
More about me :-)
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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
More about me :-)
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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
More about me :-)
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
More about me :-)
****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.