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#8099 - 07/17/06 05:03 PM Thermodynamix question for ya
DrBarr Offline
Junior Member

Registered: 07/17/06
Posts: 22
Loc: Deutschland
I have a B.S in Chemistry and this is something that's always puzzled me.
Why is it, if I put a bottle of water in the freezer not quite long enough to freeze it, it freeze almost the instant I take it out of the freezer

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#8100 - 07/17/06 05:26 PM Re: Thermodynamix question for ya
dehammer Offline
Megastar

Registered: 03/23/06
Posts: 1089
never seen that myself, but i can offer some possible reason.

1) if he bottle is wet, and you bring it out, the heat from out side would vaporize the water and cause it to remove some of the water inside

2) the air inside the refrig might be under more pressure due to it temp. bringing it out could drop the pressure enough to cause it to freeze.

as i said, not an expert, and have not seen this, so take this with a major grain of salt.
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the more man learns, the more he realises, he really does not know anything.

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#8101 - 07/17/06 06:17 PM Re: Thermodynamix question for ya
anyman Offline
Senior Member

Registered: 12/18/04
Posts: 134
i have witnessed this many times not only with water but with other bottled beverages as well (ice tea, beer, etc)

apparently the container's chemistry doesn't have a significant effect because i have observed the phenomenon with both glass and plastic bottled beverages

it likely has to do with the sudden change in temperature or more likely the sudden exposure to oxygen (and or the other elements that make up our atmosphere)

there is one notable difference related to the glass or plastic aspect...

if you catch a bottle of beer (glass) at just the right moment, you can see when you pull it out of the freezer (as you could with a plastic bottled beverage) that it is still liquid...

if you remove the cap immediately, the beer will turn to mush/slush/ice and it is ruined...however, if you wait a few seconds, say 20 to 40, the beer will remain liquid, and at what i personally consider to be the perfect temp for beer, though many experts would disagree, plus...you get the added benefit of a nice layer of frost on the outside of the bottle

beer was put into the best *glass* when it was bottled, imho

the layer of frost on the outside is rarely observed on the outside of a plastic bottled beverage under the same conditions...and the outer frost effect is never as pronounced

that said, i enjoy doing the same thing with bottled ice tea, which i get in plastic because it's not available here in glass

and i prefer a little different effect...

with bottled tea, i like to catch it at that perfect moment and open it immediately, so that it will turn to slush...tea, is not ruined when frozen like beer is...i find the taste and overall experience of drinking *iced* tea to be captial and vastly preferable to adding ice cubes to chilled (or not) tea

i'll wait with you to hear a more precise description of the process...i too would find it interesting

water -- btw -- doesn't freeze the same way as beer or tea in similar conditions...it turns into harder, albeit still small, ice (flakes or cubes for lack of a better description)

all that said...to catch any one of the three beverages in that *perfect* state for each respectively...is one of the great and very satisfying pleasures in life :-)

hmm...maybe i should get out a little more, eh :-)

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#8102 - 07/17/06 06:34 PM Re: Thermodynamix question for ya
dehammer Offline
Megastar

Registered: 03/23/06
Posts: 1089
if its something that is pressurized and you open it up, the pressure in the unopened container lowers the point where it will freeze. If you open it while it is between the pressured point of freezeing and the unpressured point, it will immeadiately freeze.

its simular to the fact that water boils at a lower tempature at higher altitudes.

its possible even that the difference in altitude of you and the point the liquid was bottled can cause a differnce in the freeze point.
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the more man learns, the more he realises, he really does not know anything.

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#8103 - 07/17/06 06:41 PM Re: Thermodynamix question for ya
anyman Offline
Senior Member

Registered: 12/18/04
Posts: 134
i have witnessed this many times not only with water but with other bottled beverages as well (ice tea, beer, etc)

apparently the container's chemistry doesn't have a significant effect because i have observed the phenomenon with both glass and plastic bottled beverages

it likely has to do with the sudden change in temperature or more likely the sudden exposure to oxygen (and or the other elements that make up our atmosphere)

the contents of most bottle beverages are under some variable pressure...so it is likely that opening the bottle and equalizing the pressures could also be a significant factor...but i think it would have more to do with the pressures inside and outside of the bottle that make the difference then more than pressures inside and outside of the icebox

having said that, i have also observed a similar effect when removing an icetray, which is not under container pressure, so maybe pressures inside and outside the box can have an effect...hmm

there is one notable difference related to the glass or plastic aspect...

if you catch a bottle of beer (glass) at just the right moment, you can see when you pull it out of the freezer (as you could with a plastic bottled beverage) that it is still liquid...

if you remove the cap immediately, the beer will turn to mush/slush/ice and it is ruined...however, if you wait a few seconds, say 20 to 40, the beer will remain liquid, and at what i personally consider to be the perfect temp for beer, though many experts would disagree, plus...you get the added benefit of a nice layer of frost on the outside of the bottle

beer was put into the best *glass* when it was bottled, imho

the layer of frost on the outside is rarely observed on the outside of a plastic bottled beverage under the same conditions...and the outer frost effect is never as pronounced on plastic

that said, i enjoy doing the same thing with bottled ice tea, which i get in plastic because it's not available here in glass

and i prefer a little different effect...

with bottled tea, i like to catch it at that perfect moment and open it immediately, so that it will turn to slush...tea, is not ruined when frozen like beer is...i find the taste and overall experience of drinking *iced* tea to be captial and vastly preferable to adding ice cubes to chilled (or not) tea

i'll wait with you to hear a more precise description of the process...i too would find it interesting

water -- btw -- doesn't freeze the same way as beer or tea in similar conditions...it turns into harder, albeit still small, ice (flakes or cubes for lack of a better description)

all that said...to catch any one of the three beverages in that *perfect* state for each respectively...is one of the great and very satisfying pleasures in life :-)

hmm...maybe i should get out a little more, eh :-)

hey, another way to get almost perfect ice tea is to freeze it completely (several hours, a day or two) then remove it and nuke it at 850watts for anywhere from 2.5 to 4mins, depending on the time in the icebox, hardness of the ice, and how your particular nuclear device works...ya might need to play with it a little, but somewhere in probably a 10-15sec range (depending on the above criteria) you'll get that mushy/slushy *perfect* consistency

drink fast...beware the "brain freeze" :-)

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#8104 - 07/17/06 09:23 PM Re: Thermodynamix question for ya
Uncle Al Offline
Superstar

Registered: 10/17/04
Posts: 540
Loc: Southern California
Phase transition requires a nucleation center to reduce activation energy and trigger kinetics. Clean liquids in smooth containers (especially viscous liquids) supercool. Ditto for liquids superheating. Melting starts at crystal imperfections that are always abundant.

PET containers are extremely smooth on the inside. Water within is typically filtered to remove particulates. There are no flaws to allow nucleation and trigger crystallization until you shock the supercooled fluid. Filtered distilled water pressed between two clean microscope slides can be cooled as low as -40 degrees and remain liquid.

Water microwaved a very smooth ceramic cup works similarly. You take it hot out of the microwave, add a teabag, and it explodes in your face.
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http://www.mazepath.com/uncleal/qz3.pdf

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#8105 - 07/17/06 11:32 PM Re: Thermodynamix question for ya
dehammer Offline
Megastar

Registered: 03/23/06
Posts: 1089
sorry al, but that sounds too much like double talk to me.

any liquid under pressure has to over come the pressure before it can crystals (freeze). water may be purified or it might not, but it will still freeze, even if it has had all the impurities removed. underpressure the air molicules trapped in the liquid prevent the crystalization until it reaches the point that the gas gets trapped in the crystals. removing the gas allows the crystals to form immeadiately.

another point is that cold air is heavier therefore increases the presure on the water in the ice cube tray. bring it into the warm air drops the pressure. it also causes an immeadiate vaporization of some of the water, carrying off a part of the heat of the water. this aids in the freezing.
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the more man learns, the more he realises, he really does not know anything.

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#8106 - 07/18/06 03:04 AM Re: Thermodynamix question for ya
DrBarr Offline
Junior Member

Registered: 07/17/06
Posts: 22
Loc: Deutschland
Quote:
Originally posted by Uncle Al:
Phase transition requires a nucleation center to reduce activation energy and trigger kinetics. Clean liquids in smooth containers (especially viscous liquids) supercool. Ditto for liquids superheating. Melting starts at crystal imperfections that are always abundant.

PET containers are extremely smooth on the inside. Water within is typically filtered to remove particulates. There are no flaws to allow nucleation and trigger crystallization until you shock the supercooled fluid. Filtered distilled water pressed between two clean microscope slides can be cooled as low as -40 degrees and remain liquid.

Water microwaved a very smooth ceramic cup works similarly. You take it hot out of the microwave, add a teabag, and it explodes in your face.
That's it Al! This is by far the most logical response. Thanks, this makes perfect since to me.

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#8107 - 07/18/06 03:24 AM Re: Thermodynamix question for ya
DrBarr Offline
Junior Member

Registered: 07/17/06
Posts: 22
Loc: Deutschland
Sorry dehammer, but that doesn't cut it. First off, I didn't say it froze when I opened it, just when i took it out. And there is no way the water bottle is "under pressure". The tiny amount of air in the top of the bottle is lower pressure relative to the pressure at room temp because pV=nRT.

Also your understanding of pressure is a little off. Cold air is not heavier, it's denser. There is no way you can convince a chemist or physicist that the pressure in a freezer is higher than the pressure outside, all other things constant. Please referrence ideal gas law above. And, pressure is force per unit area. Yes, cold air is denser but not heavier. So consider one molecule hitting the surface of a container and another molecule of the same mass hitting the same container at a higher speed. Since momentum = mass * velocity and mass is the same, the warmer molecule has greater momentum since its travelling faster.

I'm not sure I follow your post the way you meant it, but you should also know that water, as with most liquids, is almost totally incompressible. You can't simply change its pressure by changing the pressure of its environment.

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#8108 - 07/18/06 06:18 AM Re: Thermodynamix question for ya
Anonymous
Unregistered


I think the phemomenon of supercooling is to blame for what you see when you remove and ice tray or a chilled bottle that freezes when removed from the freezer. the liquid is supercooled and jarring it while moving causes it to freeze instantly. With a bottle freezing up when you take the lid off you have a pressure effect. As you release the pressure the freezing point changes and the pressure release acts similar to supercooling. Also, the bubbles that formed when the bottle was opened provide points for crystallization to form. It's all simple physics.

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#8109 - 07/18/06 12:30 PM Re: Thermodynamix question for ya
dehammer Offline
Megastar

Registered: 03/23/06
Posts: 1089
DrBarr, two things your overlooking is that

1) air in the liquid causes the liquid to become pressuriazed. that does not mean that there is any savings in space the liquid takes, but that the space inside the liquid is taken up by the air molicules. depressurizing it allows that air to come out. if you want to see this, take a soda bottle, shake it up and open it over a container large enough to take up the liquid as it comes out. after it settles compair it to an unopened bottle of the same type of soda. If you have a sensiative enough scale, it would show that the opened liquid is lighter than the unopened one, but they take up the same amount of space. the co2 in side the unopened one makes the differences

2) denser air means more molicules, which means more weight. when the door opens the air will equilaze but not immeadiately. doing so will cause the water in the ice tray to have a little more push to freeze. not much, but some. have you even open a freezer in a humid, hot enviorment, and watched the vapors fall towards the floor, usually disappating before the get far? that denser air heading for the lowest lvls.

as far as the water bottles not being pressurized, it depends on where the water was bottled. If it were bottle at sea level and your at high moutains, there is considerable amount of pressure difference. if they are in the same town and the day the water was bottled there was a high pressure ridge and you opening it with a low pressure weather pattern around you, there would be some differences. perhaps even enough by itself to cause freezing.
_________________________
the more man learns, the more he realises, he really does not know anything.

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#8110 - 07/18/06 01:28 PM Re: Thermodynamix question for ya
DrBarr Offline
Junior Member

Registered: 07/17/06
Posts: 22
Loc: Deutschland
Yikes,
Okay, with all do respect dehammer, I'm not going to argue with you. I respect your opinion and I'm new to this community but I've read several other posts and I know there there is no convincing you. So this will be my last response to you.
Concerning point 1
We are talking about water not soda. As a chemist it is vitally important to this discussion that you not change chemicals on me and try to prove a point. Surely you can understand that they are not the same. Also, there is very little disolved gas in water. And the water is no where near saturated with said gas. It is free enough to escape into the head space if it were. So, the gas has no more reason to leave the water when you remove the cap than it did while the cap was on.
On point 2
While you are totally off of the topic I started, I will address this concern anyway. Ice trays? I said nothing about ice trays. Please do not insult my intelligence by assuming I don't know that cold gas is denser than warmer gas. Bear with me, pressure has nothing to do with density directly, only temperature how much you have and the volume of the container.

I'm not going to argue the last point because it's just ridiculous and has absolutely nothing to do with my original post.

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#8111 - 07/18/06 06:14 PM Re: Thermodynamix question for ya
dehammer Offline
Megastar

Registered: 03/23/06
Posts: 1089
one major point id like to make is that there is a big difference between arguements and debate. im not argueing with you, im debating the issue with you. you have made some major points, but have not indicated that you understand that it might not all be the same thing. I'm pointing out an alternative.

someone mentioned ice trays freezeing over when they were brought out of the freezer, so i mentioned that.

yes, the thing about that is mostly about soda (which was also mentioned), but you ignored the point about the differences in the pressure of the day/place the water was bottled and the day/place it was open CAN cause some of the freeze.

that is all im saying, not that your completely wrong. you probably are right about what causes it most of the time. I dont know. as you might notice on my first post here i said take what i say about this with a major grain of salt. say about a half pound.

youll find i have a tendacy to respond in the same manner im treated. most of the people here treat me with respect and i return it. I will debate things, but i have been proven wrong on several occasions and have at times even said so.
_________________________
the more man learns, the more he realises, he really does not know anything.

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#8112 - 07/18/06 08:20 PM Re: Thermodynamix question for ya
Blacknad Offline
Superstar

Registered: 10/05/05
Posts: 901
Loc: Coventry, England
Dehammer,

I'd give this one up. You attempted to give an explanation for something you don't really understand (just as I post on evolution when I don't really understand it - therefore it comes as no surprise when I get put in my place). There are people here eminently more qualified to explain DrBarr's question.

Even I can see that you are not making much sense here.

Sometimes you gotta eat your humble pie smile

Blacknad.

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#8113 - 07/18/06 11:27 PM Re: Thermodynamix question for ya
DA Morgan Offline
Megastar

Registered: 10/17/04
Posts: 4136
Loc: Seattle, WA
Dehammer wrote:
"one major point id like to make is that there is a big difference between arguements and debate."

Give it up dehammer. Just for once demonstrate some maturity, some wisdom, some ethical standards higher than those practice by six year olds in the playground.

You are absolutely without a shred of credibility and DrBarr should neither apologize or cut you slack because he is new here. You are not just a synapse free zone. You haven't the maturity required to ever, not once, admit to an error.

Next time you get the urge to post ... post here:
http://www.mazepath.com/uncleal/effete3.png
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DA Morgan

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#8114 - 07/19/06 01:28 AM Re: Thermodynamix question for ya
dehammer Offline
Megastar

Registered: 03/23/06
Posts: 1089
Quote:
Originally posted by Blacknad:
Dehammer,

I'd give this one up. You attempted to give an explanation for something you don't really understand (just as I post on evolution when I don't really understand it - therefore it comes as no surprise when I get put in my place). There are people here eminently more qualified to explain DrBarr's question.

Even I can see that you are not making much sense here.

Sometimes you gotta eat your humble pie smile

Blacknad.
did you not see the comment about salt? i offered an opinion. did no one see this line.

"never seen that myself, but i can offer some possible reason."

notice the word "possible"

DA you would not know the difference between a debate and argument if someone wrote the difference on a ten ton rock and dropped it on you. come out of the playground and pretend your an adult. I offered a possible explanation as an opinion. now everyone seems to forget the the word opinion does not mean argument. I was told that it was impossible and i explain why i believe it is. that is adult behavior. yours is not, da.

I have more than once in this very thread said that i could be wrong, albeit not with those words. doesn't anyone understand what the phrase "taken with a grain of salt" means. what it meant in this content was to take that as a possible point of conversations, something adults do. If you can point out my point of error, do so. otherwise state your opinion and keep the insult to yourself. i don't need them and this forum does not need them.

when you express your opinion and you state at the beginning you could easily be wrong there is no need to eat humble pie, but there is also no need to be insulted for it.

i certainly never asked for an apology. DrBarr does not owe me one, and da would never notice he had any reason to.

if by cutting slack you mean allowing others to express their opinion and not slam them with insults, than he does owe me that. if you mean he has to take what i say as gospel, i never demanded that either. if my expressing my opinion does not require him to cut me slack then i don't ask for any.

THIS IS A FORUM. A PLACE FOR PEOPLE TO EXPRESS THEIR OPINIONS AND WHEN THEY ARE WRONG TO HAVE THOSE ERRORS POINTED OUT WITH DIGNATY OR ATLEAST WITHOUT INSULTS. INSULTS ARE NOT NEEDED OR ACCEPTED.
_________________________
the more man learns, the more he realises, he really does not know anything.

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#8115 - 07/19/06 02:59 AM Re: Thermodynamix question for ya
Anonymous
Unregistered


"THIS IS A FORUM. A PLACE FOR PEOPLE TO EXPRESS THEIR OPINIONS AND WHEN THEY ARE WRONG TO HAVE THOSE ERRORS POINTED OUT WITH DIGNATY OR ATLEAST WITHOUT INSULTS. INSULTS ARE NOT NEEDED OR ACCEPTED."

You're right. Let's have a bit more decorum and more dignitious behavior around here.

A bit more respect for your fellow forumites is in order around here, especially from some of you. You know who you are. I can and will cut and splice your remarks if need be. So cut the cuts and let's act like Scientists not playground bullies.

Amaranth

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