Coke physics (ice and pressure)

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Discussion Overview

The discussion revolves around the behavior of Coke in a freezer, particularly focusing on the effects of pressure and temperature on the freezing point of liquids, specifically water and soda. Participants explore theoretical aspects of phase diagrams, nucleation, and the physical properties of liquids under pressure.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant describes an experience where Coke did not freeze in the freezer, suggesting that pressure can prevent water from crystallizing into ice.
  • Another participant notes that Coke likely shares properties with water, indicating that increased pressure can keep it in a liquid state at lower temperatures.
  • A claim is made that pure water can be cooled to around -42°C before freezing, contingent on the absence of nucleation points.
  • Questions are raised about the possibility of cooling water to 1 Kelvin without freezing, with a suggestion that there may be a limit based on phase diagrams.
  • Participants reference a phase diagram indicating that the coldest liquid water can reach is about -20°C, excluding nucleation effects.
  • There is speculation that the pressure within a Coke bottle could influence the freezing point, potentially due to some of the soda freezing and increasing internal pressure.
  • One participant mentions that Coke is pressurized during packaging, which may affect its ability to expand and freeze.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the effects of pressure on the freezing point of liquids and the specific behavior of Coke. The discussion remains unresolved, with no consensus reached on the exact limits of cooling without freezing.

Contextual Notes

Limitations include assumptions about nucleation points and the specific pressure conditions of Coke, as well as the dependence on the definitions of freezing and phase behavior.

LostConjugate
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Funny thing just happened. I left my coke in the freezer, expecting the bottle to be busted I found that it wasn't even frozen at all. Liquid all the way through. Figured it was that new fake sugar chemical, but when I unscrewed the cap it instantly turned to ice.

So I guess you can prevent water from freezing if you have enough pressure on it, by preventing it from expanding it doesn't crystallize.

How cold can you get water in this case without turning it to ice? As cold as you want?

Or does the water stop releasing heat.
 
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I don't know if anybody's ever figured out the phase diagram for Coke :) but it sounds like it has the same "backwards" property that water has (that increasing pressure will keep it as a liquid in colder temperatures), which makes sense, since it's mostly water.

400px-Water_phase_diagram.svg.png


and see:
http://en.wikipedia.org/wiki/Properties_of_water

Pressure on the Y scale, temperature on the X scale), we're normally at about 10^5 Pa pressure, showing that the freezing point is normally around 273K, but the freezing point drops lower as the pressure increases.
 
Is it possible to get it down to 1 degree Kelvin without freezing? It looks like from the charter there that there is a limit.
 
DaleSwanson said:
It seems soda has about 300kPa, which doesn't seem like it would significantly change the freezing point.
http://hypertextbook.com/facts/2000/SeemaMeraj.shtml

Perhaps some of the coke froze, expanded, and increased the interior pressure enough to lower the freezing point...?
 
I think they pressurize the bottle when they pack it. So there was no way for it to expand in the first place. It was diet so there was no sugar in it, it's basically just flavored water.
 

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