Cream Soda Physics & Diving

[Rick Inman]

I think it's fair to say that this a a diving related question because it relates to liquid and gas under varying pressures in a cold environment - just like my diving! So here goes.
As I'm sitting here reading SB posts, I crack open a bottle of cream soda and I notice an interesting phenomena (I've noticed this before). Now, I've put this bottle in the freezer for about 5 minutes to get it nice and cold, and when I take it out, there is NO ice inside or around the bottle.
So I crack open the bottle. Then, slowly, as the pressure is released and the C02 begins to bubble up, ice crystals begin to form in the cream soda. In about 2 minutes I have a cream soda slush.
What causes this to happen? Lower pressure which changes the properties of the liquid and gas? Does this have anything to do with why ice forms on the top of the lake first?

 

[simbrooks]

I would think it is from the bubbles forming, and escaping (high pressure to low pressure) the can thus cooling the can and so the water on the outside crystalises. Moisture would have adhered to the outside of the can in the freezer due to condensation (it is humid in most freezers) onto the warm object. This might be roughly the same on the inside and outside hence the slush.

As for lakes, it takes a lot of energy to freeze something, particularly something with a specific conductance as water, is it a surface contact kind of thing, it starts from the very top and works in/downwards? Dont know just hypothesising around this at the moment.

 

[Rick Inman]

I would think it is from the bubbles forming, and escaping (high pressure to low pressure) the can thus cooling the can and so the water on the outside crystalises. Moisture would have adhered to the outside of the can in the freezer due to condensation (it is humid in most freezers) onto the warm object. This might be roughly the same on the inside and outside hence the slush.

As for lakes, it takes a lot of energy to freeze something, particularly something with a specific conductance as water, is it a surface contact kind of thing, it starts from the very top and works in/downwards? Dont know just hypothesising around this at the moment.

I'm sorry, let me clarify. The ice forms only INSIDE the bottle. I can actually see the little crystals forming in the middle of the liquid.

 

[simbrooks]

I'm sorry, let me clarify. The ice forms only INSIDE the bottle. I can actually see the little crystals forming in the middle of the liquid.

Do they start from the edge of the can and work inwards? My thinking is that this would be due to the cooling of the can due to the escape of the gas. We dont get weather that cold down here My drinks stay warm mostly, even when i put ice in it melts in less than a minute!

 

[Rick Inman]

Do they start from the edge of the can and work inwards? My thinking is that this would be due to the cooling of the can due to the escape of the gas. We dont get weather that cold down here My drinks stay warm mostly, even when i put ice in it melts in less than a minute!

Well, it's a glass bottle, not a can. And no, the bubbles form right in the liquid, not on any surface.
Guess you Orlandites don't know squat about ice!

 

[jonnythan]

The temperature inside the bottle drops because you're releasing pressure. The ice forms there because the humidity is so much higher there.

Get your tank valve wet then crank it open and wait a minute. You'll see ice crystals. Or grab a CO2 paintball tank and press the pin valve so it's full open. The thing gets encased in frost in a matter of seconds.

 

[simbrooks]

Well, it's a glass bottle, not a can. And no, the bubbles form right in the liquid, not on any surface.

I should learn to read

Guess you Orlandites don't know squat about ice!

You are correct there - most people here are glad of that fact I however am enjoying this cooler weather in the 40's and 50's! Maybe i should leave this thread to the physics experts

 

[DepartureDiver]

The term (at least when I knew it) was called supercooling.

 

[Fly N Dive]

you dont even need that much pressure, bottled water will do the same thing. its really cool. i think it happenes because the pressure lowers the freezing point of the liquid,but when the pressure is realesed it freezes.

 

[Firefyter]

you dont even need that much pressure, bottled water will do the same thing. its really cool. i think it happenes because the pressure lowers the freezing point of the liquid,but when the pressure is realesed it freezes.

You're on the right track, but not quite there. Increased pressure raises the boiling point of a liquid. This is the principle that allows pressure cookers to cook faster than regular pots, as the water in the cooker gets a lot hotter than open air cookers, i.e. >212º F or >100º C. Since this is true, the reverse is also true. If a liquid under pressure is cooled, then the pressure is released, the freezing point is also changed, at least temporarily.