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On 9/5/2011 5:50 PM, Patrick Elliott wrote:
> Worse than that, in certain conditions you can "hyper-heat" water, and,
> I assume, probably super cool it, without changing state. In the former
> case you just need a container that has "no" places for bubbles to form.
> Not sure what you would need to do in the later case to make it happen,
> if you could.
You can super-cool water. Fun trick:
Get some bottled water, leave it in the freezer for approximately 30
minutes (some experimentation will be needed to determine the exact
amount of time needed for the best effect) remove it from the freezer,
note that it is still liquid, bang it against something to get a crystal
to nucleate, then watch the ice form right in front of you. Enjoy your
slushy, cold water.
--
~Mike
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On 9/6/2011 3:04 AM, Invisible wrote:
> I see what you did there.
>
> I've got a box of hand warmers at home. They contain a super-saturated
> solution (of what I don't know). Once you provide a nucleation point,
> the whole lot crystallises within a few seconds. It also gets quite warm
> in the process. (This is what makes it good for warming your hands.)
Sodium acetate. I've made my own countless times in my life. And
recently made a big enough batch to create the super-saturated solution
(actually melted crystals) to crystallize. Very cool to watch. Drop a
tiny sodium acetate crystal in, and it grows out from that and warms the
container nicely.
--
~Mike
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On 9/6/2011 5:08 AM, Invisible wrote:
> Unrelated, but I note that dissolving ammonia in water is an endothermic
> reaction. That, apparently, is how Victorian icecream was made. So I
> guess the question is, WOULD YOU EAT IT? ;-)
There is a certain type of candy or treat (Finnish, I believe?) that is
seasoned with ammonium chloride ....) They eat it, though ammonia
solution I think I would avoid.
--
~Mike
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>> I've got a box of hand warmers at home. They contain a super-saturated
>> solution (of what I don't know). Once you provide a nucleation point,
>> the whole lot crystallises within a few seconds. It also gets quite warm
>> in the process. (This is what makes it good for warming your hands.)
>
> Sodium acetate. I've made my own countless times in my life. And
> recently made a big enough batch to create the super-saturated solution
> (actually melted crystals) to crystallize. Very cool to watch. Drop a
> tiny sodium acetate crystal in, and it grows out from that and warms the
> container nicely.
And here I was thinking it was sodium thiosulphate...
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On 9/6/2011 11:20 PM, Darren New wrote:
> On 9/6/2011 18:11, Alain wrote:
>> Le 2011/09/06 15:59, Darren New a écrit :
>>> On 9/6/2011 11:34, Jim Henderson wrote:
>>>> I've also had it happen to me.
>>>
>>> Me too.
>>>
>>
>> Put a pinch of croase sand in the container.
>
> Yeah, because Croase sand goes so well with tea.
>
>
It adds a nice crunch.
--
~Mike
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Le 06/09/2011 12:08, Invisible a écrit :
>
> Unrelated, but I note that dissolving ammonia in water is an endothermic
> reaction. That, apparently, is how Victorian icecream was made. So I
> guess the question is, WOULD YOU EAT IT? ;-)
Hydration of common salt is endothermic. The fusion temperature of the
mix is usually lower than the fusion of clear water.
(For road usage: Hydration of CaCl2 is exothermic, but the one of NaCl
is endothermic; CaCl2 is used in countries with very low temperatures on
their road)
For the preparation of ice-cream (well, rather sorbet (water-based
ice-cream, using fruit juice, water), than the rich ice-cream with cream
of milk, eggs and other stuff), you only have to cool the recipient and
the preparation a bit below 0°C (which can take a lot, as freezing water
has a lot of joules to expel): using a recipient with an internal
container and an external container, you prepare the sorbet in the
internal container, and have the water+ammoniac mixed in the external
container.
(If you remember your chemistry about mixing acid and water (you drop
one in the other, but avoid the other way round), can you guess what
must be added to what (ammoniac is a base)) ?
Nothing related to the fancy preparation of ice-cream with liquid
Nitrogen (pour liquid nitrogen over the preparation, and mix with energy
and a wood spatula (and some goggles, and some heavy gloves)!).
I would be interested in a preparation with liquid Oxygen, served at a
table of smoking people... well, soon-ex-people. I'm just afraid the
reaction with liquid Oxygen would also change the taste too much.
(oxidation power is very strong)
--
Software is like dirt - it costs time and money to change it and move it
around.
Just because you can't see it, it doesn't weigh anything,
and you can't drill a hole in it and stick a rivet into it doesn't mean
it's free.
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Am 20.09.2011 15:11, schrieb Mike Raiford:
> You can super-cool water. Fun trick:
>
> Get some bottled water, leave it in the freezer for approximately 30
> minutes (some experimentation will be needed to determine the exact
> amount of time needed for the best effect) remove it from the freezer,
> note that it is still liquid, bang it against something to get a crystal
> to nucleate, then watch the ice form right in front of you. Enjoy your
> slushy, cold water.
NOT recommended with glass bottles >_<
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On 9/20/2011 10:11 AM, clipka wrote:
> Am 20.09.2011 15:11, schrieb Mike Raiford:
>> You can super-cool water. Fun trick:
>>
>> Get some bottled water, leave it in the freezer for approximately 30
>> minutes (some experimentation will be needed to determine the exact
>> amount of time needed for the best effect) remove it from the freezer,
>> note that it is still liquid, bang it against something to get a crystal
>> to nucleate, then watch the ice form right in front of you. Enjoy your
>> slushy, cold water.
>
> NOT recommended with glass bottles >_<
Just don't bang it too hard... ;)
--
~Mike
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Am 21.09.2011 14:41, schrieb Mike Raiford:
> On 9/20/2011 10:11 AM, clipka wrote:
>> Am 20.09.2011 15:11, schrieb Mike Raiford:
>>> You can super-cool water. Fun trick:
>>>
>>> Get some bottled water, leave it in the freezer for approximately 30
>>> minutes (some experimentation will be needed to determine the exact
>>> amount of time needed for the best effect) remove it from the freezer,
>>> note that it is still liquid, bang it against something to get a crystal
>>> to nucleate, then watch the ice form right in front of you. Enjoy your
>>> slushy, cold water.
>>
>> NOT recommended with glass bottles >_<
>
> Just don't bang it too hard... ;)
Well, bang as softly as you might - I wouldn't want to be close to /any/
glass bottle in which water is busy crystallizing.
(Hint: The specific density of ice is only about 92% that of ice-cold
water.)
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On 9/21/2011 1:00 PM, clipka wrote:
> (Hint: The specific density of ice is only about 92% that of ice-cold
> water.)
Oh, right... Water expands when freezing.
So long as there's sufficient air at the top, and the glass bottle is
thick enough....
--
~Mike
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