# Scientific Enquiry



## Bill Mattocks (May 19, 2009)

This is just a question for those who might know a bit about thermodynamics.

I recently turned my fridge to a lower setting - that is, I wanted things in the fridge to be colder.  It is on the next-to-lowest temperature setting.

In my fridge, I have beer in 12-ounce bottles, 2-liter bottles of soda, a jug of filtered water, a pint of milk, and some 'vitamin' 1-quart non-carbonated waters of various sorts.

I noticed the other day that my vitamin water bottles had all frozen solid.  Yet for some reason, nothing else was frozen.

Then, I noticed that after I had opened a 2-liter bottle of soda and poured myself a glass, the soda remaining in the bottle began to freeze like a slushy drink within an hour.

I thought that perhaps the soda in the open bottle was starting to freeze because the empty space in the bottle had been replaced by air, but my pint of milk has been opened for nearly a week, and it is not frozen.

So what would cause soda in a 2-liter bottle to freeze, but only AFTER it had been opened for the first time, and 'vitamin' water in 1-quart bottles to freeze, but not unopened bottles of soda, beer in glass bottles, or an opened carton of milk?

I suspect the alcohol in the beer lowers its freezing point.  How about the rest?


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## Twin Fist (May 19, 2009)

the water bottles froze because they are water

the other stuff int he soda makes the freezing point lower, so it hadnt frozen yet.

you opened the 2 litre, released some of the gas, causes it to freeze easier than when it hadnt been opened

more or less


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## Carol (May 19, 2009)

Yup.  The alcohol lowers the freezing point.   Put a bottle of vodka (even the cheap stuff) in the freezer and it won't freeze at all.

Not like I ever tried that or anything...I just learned that in organic chemistry, yeah yeah that's it, chemistry class.  :angel:

The unopened bottles of soda are pressurized, which lowers their freezing point.  The additives also lower the freezing point.

Milk isn't pressurized so it wouldn't matter if the carton is open or not.  It has a lower freezing point than water by about a half degree C, or approx. 1 degree F.  Doesn't seem like much but in a cold fridge that can be the difference between water freezing and milk not freezing.

Another important difference is where the items are located in the fridge.  Refrigerators provide cold storage for your perishables but the temperature isn't even throughout.  You might have items that freeze on some shelves but not others.  Or you might have an item that freezes when on a shelf, but doesn't freeze when placed in the door rack.

Like the freezing point of milk, the temperature difference isn't that great, but in an area that cold, the difference of a fraction of a degree Celsius can mean the difference between something freezing and not freezing.


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## elder999 (May 19, 2009)

Bill Mattocks said:


> This is just a question for those who might know a bit about thermodynamics.
> 
> I recently turned my fridge to a lower setting - that is, I wanted things in the fridge to be colder. It is on the next-to-lowest temperature setting.
> 
> ...


 

That's actually several questions. :lol:

The soda freezes upon opening because it is, in essence, a super-cooled solution: a liquid with other substances dissolved in it that has been lowered _below_ it's solvent's freezing point, but is capable of staying liquid at a lower temperature because of the "other stuff," principally, CO2, which, upon opening, exits the bottle, lowers the concentration, raises the freezing temperature and, _voila,_ the remaining liquid freezes. Same thing would likely have happened on opening the beer , if it were cold enough already-the alchohol in beer won't limit its freezing; put some in the freezer, and see for yourself.Ditto the remaining soda.

It might have happened upon mere shaking-you must have a soft touch. This is, btw, further evidence that sodas are evil. :lol:

The vitamin water is, basically, water-it's freezing temperature hasn't been lowered, so it froze.


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## Bill Mattocks (May 19, 2009)

Thanks, all, and most of that makes sense to me - but the open jug of filtered water did NOT freeze.  The sealed bottles of vitamin water did.  They are smaller bottles (1 quart versus 1 gallon), but both essentially water.

I now understand the part about the sealed soda not freezing and then freezing quickly after being opened.  But the water is still throwing me.

OH, and they're all on the same shelf in the fridge, the top (largest) shelf.  I have also tried to move the bottles around in the fridge from back to front - doesn't seem to make a difference.  The open jug of filtered water does not freeze, the sealed smaller bottles of vitamin water do.


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## Twin Fist (May 19, 2009)

larger container takes longer to get the entire contents to the freezing point


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