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From: Jonathan on 27 Jan 2010 21:14

"PD" <thedraperfamily(a)gmail.com> wrote in message
news:7407f144-9f1d-4798-8ac0-2992390820b1(a)g29g2000yqe.googlegroups.com...


> Water is a better thermal conductor than air.

Exactly! I think the way to explain it 'plainly' would be to
ask the question, what's the fastest way to cool off a
red hot kitchen pan, with water or air?

Especially if she's the kind of cook that uses the smoke alarm
to tell when dinners ready.


> This is why 28C water feels cool compared to 32C air, because it wicks
> heat out of a 37C body faster. For that matter, 32C water would feel
> cooler than 32C air for the same reason.
> On the other hand, 28C water would wick heat INTO a bottle of beer
> faster than 32C air, for the same reason.

> This should explain things even to an idiot.


From: Peter Webb on 28 Jan 2010 05:56

"Jonathan" <Home(a)Again.net> wrote in message
news:vIKdnY4zyZRCY_3WnZ2dnUVZ_tqdnZ2d(a)giganews.com...
>
> "PD" <thedraperfamily(a)gmail.com> wrote in message
> news:7407f144-9f1d-4798-8ac0-2992390820b1(a)g29g2000yqe.googlegroups.com...
>
>
>> Water is a better thermal conductor than air.
>
> Exactly! I think the way to explain it 'plainly' would be to
> ask the question, what's the fastest way to cool off a
> red hot kitchen pan, with water or air?
>

I used the analogy of the hot air from opening an oven door doesn't fry your
face off.

I suspect a more important factor is that water has a far higher thermal
mass than air; cooling the air for a few centimetres around the bottle only
raises the beer temperature slightly, whereas water gives up far more heat
per unit of volume.




From: jmfbahciv on 28 Jan 2010 08:58
Yevgen Barsukov wrote:
> On Jan 27, 5:03 am, "Peter Webb"
> <webbfam...(a)DIESPAMDIEoptusnet.com.au> wrote:
>> Its summer where I am now, and on the weekend my girlfriend came over for a
>> swim in the pool.
>>
>> The pool is shady, heated to 28 degrees C, the outside air temperature was
>> maybe 32. She goes into the house, brings out 2 beers that have been sitting
>> in a fridge at 4 degrees, and then proceeds to put them in the water to keep
>> them cool!
>>
>> I know that's not right, and I even know why its not right, but how to
>> explain it? My attempts didn't work, but then she is an idiot.
>
> You are right on the short term (as you are planning to drink the bear
> immediately) but she is right on the long term (maybe she is planing
> to let
> it sit there for hours).
>
> Lets see what will happen
> 1) air - after several hours, but beer will change from 4 to 32C
> 2) water - after 15-30 min warming, beer will change from 4 to 28C,
> but than
> it will stay at that temperature which is less than 32C.
>
> So, over short periods 1 is better, over long periods 2 is better.
> Are you right or wrong?
> Not so clear anymore. Depends on the intentions towards the beer.
>
> Looks like you had a bit of wishful thinking there - finish the beer
> quickly and go over to more interesting things. She might have
> different ideas. So much can be derived from beer cooling
> strategies...
>
Very nice analysis :-).

/BAH
From: PD on 28 Jan 2010 09:30
On Jan 27, 8:14 pm, "Jonathan" <H...(a)Again.net> wrote:
> "PD" <thedraperfam...(a)gmail.com> wrote in message
>
> news:7407f144-9f1d-4798-8ac0-2992390820b1(a)g29g2000yqe.googlegroups.com...
>
> > Water is a better thermal conductor than air.
>
> Exactly! I think the way to explain it 'plainly' would be to
> ask the question, what's the fastest way to cool off a
> red hot kitchen pan, with water or air?

Well, that is actually due to another property of water, its
extraordinarily high heat capacity -- which means basically how much
heat it can absorb per temperature change. The heat comes out of the
pan an into the water, but the pan cools off a big temperature change
(because it has a LOW heat capacity) and the water only warms up a
small heat capacity (because it has a HIGH heat capacity).

So in this case, it is both the relatively higher conductivity of
water AND the higher heat capacity of water, compared to air, that
contributes.

>
> Especially if she's the kind of cook that uses the smoke alarm
> to tell when dinners ready.
>
> > This is why 28C water feels cool compared to 32C air, because it wicks
> > heat out of a 37C body faster. For that matter, 32C water would feel
> > cooler than 32C air for the same reason.
> > On the other hand, 28C water would wick heat INTO a bottle of beer
> > faster than 32C air, for the same reason.
> > This should explain things even to an idiot.

From: Darwin123 on 28 Jan 2010 10:01
On Jan 27, 6:03 am, "Peter Webb"
<webbfam...(a)DIESPAMDIEoptusnet.com.au> wrote:
> The pool is shady, heated to 28 degrees C, the outside air temperature was
> maybe 32. She goes into the house, brings out 2 beers that have been sitting
> in a fridge at 4 degrees, and then proceeds to put them in the water to keep
> them cool!
>
How do you know she was trying to cool the beer?
Maybe she was trying to cool the pool down to below 28 degrees.
Or maybe she wanted to warm up the beer.
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