Does pressure lower the freezing point?

Everyday I have a Pepsi at noon. They are in the fridge in the carriage house. I got mine today, opened it, and took a drink. Nice and cold. Second drink - slushy (one side of carriage house not heated). So did it become slushy due to the lower pressure or was the slush suspended due to the pressure? It must have been just at the freezing point either way.

There was enough slush that I didn't miss it first drink. It was either not there or lower in the can.

BTW - I lit the stove in there. No one needs to clean up a case of busted pop in the fridge!

Want me to try to sound smart or admit I copied this from the net? I saw this on TV on Outrageous Acts of Science. This is the explanation for beer,but I assume it applies to soda as well.


Ok, here's how it breaks down. Water freezes in a unique way compared to most other liquids. Water freezes in a crystalline latice structure that looks like layers of hexagons. That's why water expands when it freezes into ice.

Now the second part of the answer is that when you dissolve something like salt or sugar into water, you lower the freezing point of water. The additives or solutes disturb the way that water freezes by interfering with the water molecules as they try to freeze into their lattice pattern. This disturbance does not fully prevent water from freezing, it only lowers the freezing point. As long as it's cold enough, water can still freeze into ice. By lower the freezing point, the water needs to get colder and colder to be able to turn into ice. The other side of this is that you can dissolve more things in a hot liquid than a cold liquid. When you dissolve something to its limit into a liquid, it's called saturating the liquid. Also, you can dissolve a lot of something in a liquid when it's hot, but then let it cool without disturbing it and it will be a supersaturated solution.

Beer is not only a solution (something dissolved in water), it is a special solutions because of carbonation. The process of carbonation involves forcing carbon dioxide bubbles through water to force the carbon dioxide to dissolve in the water or in this case beer. When they bottle beers, the company is actually supersaturating the beer with carbon dioxide, that's why it always foams a little when opened.

Because beer has carbon dioxide in it, it's freezing point is lowered so it is less likely to freeze. When you cool the beer down below freezing with the cap on, the beer will not freeze, but once you open it, you release the carbon dioxide. As the beer quickly loses the dissolved carbon dioxide, the freezing point for the beer quickly goes up. Once freezing point gets up to the temperature of the superchilled beer, the beer freezes and turns into a solid.

E=MC2

Long story short... When you open a carbonated beverage, some of the CO2 evaporates, causing a slight decrease in temperature. In this case it was just enough to cause the contents to freeze.

Ya,the way they showed it on TV,for some reason if you tap the bottle it will start the reaction quicker. Something about the tap creating a larger bubble to escape all at once or something.

Sure. Even though heat rises who ever heard of a lake freezing from the bottom up? Or maybe its the fish swimming around that keeps the water moving? Hmmm.

There is a very, very fine line when beer is cold enough that when you open the bottle, a tiny bit of frost forms, and it's almost like drinking from a frosty mug. TOO cold, however, and it all gets slushy and yuck!

This fall during deer season a friend stopped by my camper when I wasn't there, he left two bottles of Pepsi on the front step. Quite cold out, by the way. When I got there about noon the next day one bottle was frozen solid and the other was not, it looked like it came right out of the fridge. Both bottles side by side, and in the shadow of the camper. What gives?? On a side note, you guys do know that heat does not rise, don't you?

It will Freeze When Air hits it, And Or... Shaken up...When it is Below freezing. Larry

water freezes at a lower temperature when the pressure increases.carbonated beverages have a different phenom due to the absorbed co2.

Simple answer is YES.

COMPLICATED answer follows:

<img src = "http://i.stack.imgur.com/n6LXj.gif">

Phase diagram of pressure-temperature relationship of water:

I don't think it actually has much effect. In a full vacuum, water can't technically exist. If liquid water is introduced into a vacuum, it would immediately evaporate. If ice was thrown into a vacuum at a low enough temperature, it would remain ice. But -50 wouldn't do it, it would have to be extremely cold. At a higher altitude, I think water will still freeze at very close to 32F/0C, but it will evaporate at a lower temperature than 212F/100C. The same way a persons blood will boil above 62,000-63,500 feet. In an aircraft capable of high altitudes, it is possible for ice to form on the wings at say 30,000 feet, and at 65,000'+ it could evaporate from the wings, never becoming a liquid.

So basically, the air pressure has very little bearing on the freezing temperature of water.

If I'm reading this diagram correctly, at around 0.9 Kpa(0.13psi), water can no longer can exist as a liquid. At over 500Mpa(72,500psi), the freezing point of water begins to change slightly, and falls down to around -20C at around 720Mpa(104,400psi). You will realistically never see the freezing point of water change.

The question wasn't about water though,it was about Pepsi and the carbonization and sugar effect the freeze point. Read what I posted about it.

Yes! I just discovered this a few days ago. I had 4 2 liter bottles of coke zero in the back of the pickup. Three were full, one I took some out of, like 16-20ozs. Went from Lansing Mi to Battle Creek. When I got there the 3 full ones were still liquid very cold but liquid. The partial was froze solid. I tapped one of three for the return trip and it had froze solid and the two remaining full ones were still 100% liquid.

If you decrease the pressure, the freezing point of water will increase ever so slightly. From 0° C at 1 atm pressure it will increase up to 0.01° C at 0.006 atm. This is the tripple point of water. At pressures below this, water will never be liquid. It will change directly between solid and gas phase (sublimation). The temperature for this phase change, the sublimation point, will decrease as the pressure is further decreased.

If the melting point of water didn't go down with pressure, ice skates wouldn't work. The reason ice is so slippery is that a film of water forms when you stand on it. Think about it: what other solid substance is as slippery as ice?

It's a common phenomenon for carbonated beverages to freeze when you open them. As any high school kid who hid a case of beer in the trunk of his car.

As stated before, water is about the only substance that expands when it freezes. That accounts for a number of odd characteristics in addition to the two I just mentioned. For example, the oceans would freeze from the bottom up if water contracted as it froze.

I'll expand this some more. I often have a case of bottled water in the mud room and in the winter, one bottle will freeze solid but the one right next to it will remain liquid.

This is just plain bottled water, nothing else added to it. How does that happen?

Donovan from Wisconsin