Cream Soda Physics & Diving

[DepartureDiver]

Depends on whether the container is open or closed. Hot water will tend to vaporize a large portion of its volume, thus allowing it to ultimately cool and freeze faster.

Okay. I gotta bite at this one. So are you saying if I just finished boling some water and then put it in a freezer with a control filled with water just above freezing that the boiling water will freeze faster? Of course I took the example to the extreme, but I can't make the hot water freezing faster than colder water story make sense.

 

[jonnythan]

Okay. I gotta bite at this one. So are you saying if I just finished boling some water and then put it in a freezer with a control filled with water just above freezing that the boiling water will freeze faster? Of course I took the example to the extreme, but I can't make the hot water freezing faster than colder water story make sense.

I've done it before. Turn the tap all the way on hot and fill up an ice tray.. then immediately fill up another with water from a cold tap. Toss both in the freezer.

The one with the hot water will be frozen first, but the cubes will be half the size. It really does work that way.

Not sure if the water was actually boiled on a stove.. the cubes might be even smaller then. Try it out, you'll probably be surprised.

 

[DepartureDiver]

Not sure if the water was actually boiled on a stove.. the cubes might be even smaller then. Try it out, you'll probably be surprised.

I hate to admit it, but I probably will try it out ... hey, I have no life anyway.

 

[-=>Larry<=-]

good points and physics in your post ... but in this situation, a supercooled liquid's temperature is already below freezing, so it is not the temperature drop that does it ... it was the seeding from the nuclei (in this gas the CO2 coming out of solution).

Phase diagrams show the relationship between pressure / temperature and the physical state of a material.

I pulled one for water up and looked:
http://www.lsbu.ac.uk/water/phase.html

and notice that water freezes at a relatively constant temperature - BUT - the slope of hte curve is negative and gets REAL inflected at a pretty high pressure.

SO - It's perfectly reasonable that water, under pressure, can get cooled to a lower temperature than it would freeze at for a normal pressure [super-cooled] - but when the presure is released, it would freeze quickly assuming there is sufficient energy, or lack thereof, there to do the phase change.

[Hang on Sue!]

 

[DepartureDiver]

and notice that water freezes at a relatively constant temperature - BUT - the slope of hte curve is negative and gets REAL inflected at a pretty high pressure.

SO - It's perfectly reasonable that water, under pressure, can get cooled to a lower temperature than it would freeze at for a normal pressure [super-cooled] - but when the presure is released, it would freeze quickly assuming there is sufficient energy, or lack thereof, there to do the phase change.

Good search ... and now we have yet another term we can discuss ... the Triple Point. You are correct that pressure does affect it. But as you also pointed out, the temperature at which ice will freeze (or melt) is relatively constant as shown by the near vertical line until the pressure becomes high. So at the pressure inside a cream soda bottle, the freezing temperature would be roughly the same and it was the nucleation that started the freezing (Dr. Deco should see this thread since he loves a good nuclei story). Just as in the cool (sorry) bucket example where the agitation caused nucleation for the freezing to start ... which occurred at the same pressure. Just fyi for those that don't know, 273 degrees Kelvin is the same as 0 degrees Celsius (32 F). Kelvin is on the same scale as Celsius ... it just uses a different starting point. So to get Kelvin you always add 273 degrees to the Celsius temperature. 0 Kelvin is absolute zero or minus 273.15 Celsius.

 

[Rick Inman]

My wife, looking over my shoulder, reading these posts: "You guys are all bananas. Why don't you just drink the stupid thing."

Sigh... Sometimes she just doesn't get it.

BTW, yes, my frig is super-cool.

 

[DepartureDiver]

My wife, looking over my shoulder, reading these posts: "You guys are all bananas. Why don't you just drink the stupid thing."

cuz of the supercooling it froze before we could ... now we have to talk about it melting before we can get to the drinking part.

 

[Mako Mark]

-Which freezes first hot water or cold water, Anyone?

Rick

Hot water will freeze first.

 

[Hank49]

Hot water will freeze first.

I've never tried a test on this but I've heard it's true. But how? The hot water has to cool to freeze and at some point as it cools it will be the exact temperature of the cold water...but then it goes on and freezes faster. Huh?

 

[jonnythan]

I've never tried a test on this but I've heard it's true. But how? The hot water has to cool to freeze and at some point as it cools it will be the exact temperature of the cold water...but then it goes on and freezes faster. Huh?

This was about 2 pages ago:

Hot water will tend to vaporize a large portion of its volume, thus allowing it to ultimately cool and freeze faster. Put both in a bottle and the cold water will freeze first.

So you get ice faster, but you get a lot less of it.