Physics question. Why's my Coke still frozen?

[carpetbagger]

I know this is probably more my laziness in figuring it out than my lack of knowledge of physics, but here goes...

Sometimes I put my Coke in the freezer to cool 'em down more and more quickly. Of course, when they freeze too much, they expand.

Is it my imagination that after the can expands, the pop remains frozen for an inordinate amount of time, more than you'd expect from just the fact that it gets completely frozen, or is there something to it?

[Don_G]

1. Chemicals Maybe?

A Coke is a mixture of water, corn syrup, phosphoric acid and other stuff so the freezing point is probably well below 32 degrees.

[pmbryant]

2. I do that a lot

If the coke has frozen so much that is expands, it has frozen into a solid block of ice. Solid blocks of ice always take longer to defrost than a mass of smaller chunks since the surface area exposed to warmer air is much smaller.

This is just an educated guess, of course. Despite my vast experience in freezing soda cans, I've never done an experiment with them. ;-)

--Peter

[SoCalDem]

3. The "foamy" part stays frozen longer

and when it thaws, the fizz will be mostly gone too :(

Lucky for you it did not ooze out all over the inside of the freezer (that's happened to me):(

[rock]

4. While normally you can't heat water beyond 212 degrees

(because it boils), you can take frozen water to whatever temp your freezer is capable of. Maybe you got it set well below 32 degrees.

[Superfly]

5. You can heat water beyond 212 degrees

under certain atmospheric and crustal conditions. Water coming out of the so-called "black smokers" (VMS deposits for geologists) is more that 400 degrees.

[pmbryant]

6. This is a good point

Once the soda is frozen solid, its temperature can drop further. So, once out of the freezer, the whole block of 'soda ice' has to warm up to 32 degrees before it can even start melting.

Then, the fact that it is a single solid block of ice will cause it to melt rather slowly as I described above.

--Peter

[tridim]

7. There's nothing better than a perfectly frozen Coke

When it just starts to form ice crystals and it's all slushy. You soda freezers know what I mean. I find that cracking the seal just a tiny bit helps the process. Mmmm, refreshing!

The worst is the stage right after this when it freezes into a mass of ice and the water separates from the syrup. Even opening the can with a can opener is a messy, tasteless disaster.

Soda science 101. :)

[LARED]

8. One possibility

is that when the can expands it relieves surface pressure on the ice. The melting point of ice is raised if it is under pressure. That's why ice skates are so slippery. The high pressure created by all your weight distributed over a thin blade turns the ice to water creating a very slick surface.

[carpetbagger]

10. That's part of what I was thinking about.

Thanks.

[LARED]

12. Your welcome n/t

[carpetbagger]

9. Thanks. Followup- does it require more work...

...now that the can's bigger for the ice to melt?

P.S. I apologize for my nonspecificity, but the drink is Diet Dr. Pepper, so there's no corn syrup. I use Coke in the generic sense, since I usually use the work "pop" (instantly identifying myself as a carpetbagger), but "pop" in the freezer could be confused with popsicles.

[Enraged_Ape]

11. As the pressure in the can drops, the temperature drops further

I think I remember this from college chemistry (the Ideal Gas Law, or Boyle's Law, or something). The Coke contains pressurized CO2 in solution. When you pop the top, the temperature drops below what it was when you took it out of the freezer.

I do know this is the reason why you can take a liquid Coke out of the freezer and it will freeze solid when you pull the tab.