Scientific OT question

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Pete Allan

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Oct 29, 2003
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I have a Neighbor that tries to stick me with tough questions Well today he got me. He said this morning when he got into his truck there was a new bottle of water sitting on the seat and it wasn't frozen. He said he picked it up and shook it to see if it was just clear ice and found it to be liquid but within a heart beat it was solid white ice. He looks at me and says "tell me what happened"? Now when I was in school I studied every thing in science I could find but this has me clueless. I even remember all the stuff about Latent Heat reguarding changing state from solid to liquid to gas and I think it has something to do with that BUT.
Turn those brain cells on and tell me what I am overlooking here :o
 
Supercooling.
It's a known phenomenon. A liquid below it's "freezing point" can have just the slightest vibration applied and crytallize almost instantly.
 
it could happen when it was a bottle of water with gas in it. When u open up a bottle of water with gas in it, and the water temp is just above 0° C. When the pressure drops in the bottle the temp will fall down and the water can start to solidify and form ice.

But not by holding it. U need some pressure loss in the bottle.
 
The triple point of water is what was viewed. The above post is correct. Have you ever put a warm beer in the freezer and left it in there just a little too long and upon opening it all seems well at first but very soon it begins to ice up? The triple point is a region of temperature which water can exist in all three known states, gas, liquid and solid.

RL
 
This is actually not entirely off topic, since it is a good demonstration of how many of the crystaline structures in steel nucleate. Steels have been produced that are austenitic at room temp but will transform to martensite if impacted. The driving force behind many of the tranformations we mess with is stored energy in places like the grain boundaries.

The real wild thing is if your friend had a probe on the bottle when he shook it, :D he would have noticed a spike in temperature as the ice crystals formed. Same thing happens when you cool austenite slow enough to make pearlite, the transformation is exothermic. Which could lead to speculation about how much fine pearlite may be self generating if it begins to form, since it could retard the cooling process simply by forming :confused: . I just thought I would throw that at yah, just incase you didn't have enough to worry already. ;)
 
The exothermia, "heat of crystallization" in chemisty lingo, makes sense because as the crystal lattice forms, the "units", whether they be ionic or organic molecules or metallic atoms, are going to a less energetic state as a stable solid from being in solution. The vibrations of each "unit" have to slow down to "fit in". In order for that to happen the energy has to go somewhere. It becomes heat.

A good example is cited in the link I posted above: the little "heat pads". A solution in a metastable state, things happen when the little metal tab is clicked inside the bag, nucleation is induced, the dissolved salt rapidly turns into a mass of hydrated crystals, and the phase change liberates its energy as heat.

It is interesting to make correlations between the crystallization work I did with organic compounds and the steel transitions of heat treating. Thanks for the insight, Kevin.
 
fitzo said:
..A good example is cited in the link I posted above: the little "heat pads". A solution in a metastable state, things happen when the little metal tab is clicked inside the bag, nucleation is induced, the dissolved salt rapidly turns into a mass of hydrated crystals, and the phase change liberates its energy as heat...
Click to expand...

When I was young, my parents had one of those little hand warmer pads for ice fishing, I was always getting in trouble for clicking it just to watch the crystals form, then it would have to be soaked in a pan of hot water to reset it back to liquid.
 
I've actually witnessed this happening with freezy pops, the kind that look like colored water in little flat plastic tubes.

If you got kids you probably have the pops already, put 'em in the frezzer and keep checking on them periodically, when you see that some are starting to freeze/turn to slush, and some are not, take the ones that aren't frozen an shock them by slapping it against the table, now some flavors are better at this than others, but I'm not sure which, after slapping you should see an ice crystal start to form, usually by shaking/agitating the liquid it speeds up the process.

I have no idea why this happens, I just know I've seen it and have shown it to many people.
 
The only problem I have with this is the part where it makes my beer turn to ice. We're talking a serious situation here.
 
Tom, I hate when that happens too. You get it home too late and try to hurry it up n the freezer and then forget just a little too long. I mean you're nursing a warm one and just loose track. It sucks.

If my memory serves correctly the triple point of water at sea level on earth is 32 F / 0 C. That is, if I have temp correct, water exists in gas, liquid and solid simultaniuosly. It is a slush to view and feel but still evaporates.

RL
 
Roger, you are correct abut the temperature (well actually it is 0.01C ;)) but pressure is only 611.73Pa (0.006ATM) while I belive pressure at sea level is defined as 101.33kPa.
 
WRONG!
When WATER freezes it becomes ICE.
Water-Ice expands - one of the few substances that does that.
Typically substances contract when cold/frozen.
However, there is a temperature at which ICE contracts.
 
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