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stinsonbr
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Can someone explain how this happens?
I am not sure, if that would be a part of the answer then please explain it.DrClaude said:What is the temperature of the ice?
Yes and no...stinsonbr said:I had read that it had something to do with the process of ice melting making the ice itself colder?
Heat is given up by the solid phase (ice) in the process of dissolving/diluting alcohol.Bystander said:Google "freezing point depression."
Actually, that isn't true(you aren't the only one who said it...): they meet at the freezing temperature of the liquid, regardless of either's starting temperature.Ibix said:The ice cools the drink; the drink warms the ice. The will meet at a temperature in the middle somewhere.
This is exactly what I was trying to fish out. Can you give an "explain like I'm five" explanation on how this happens?russ_watters said:Actually, that isn't true(you aren't the only one who said it...): they meet at the freezing temperature of the liquid, regardless of either's starting temperature.
So that means, counter-intuitively, that they can end up colder than either started.
So the only thing that matters here is the freezing temp of the drink (as long as you add enough ice to reach it).
Not necessarily. Put a cube of ice from the freezer in liquid nitrogen. Do you expect the nitrogen to freeze?russ_watters said:Actually, that isn't true(you aren't the only one who said it...): they meet at the freezing temperature of the liquid, regardless of either's starting temperature.
That can happen below 0, if the ice starts cold enough.NihalRi said:As soon as the ice and alcohol reach the same temperature the heat exchange will stop.
A five year-old doesn't have much chance here, but I'll try to be basic...stinsonbr said:This is exactly what I was trying to fish out. Can you give an "explain like I'm five" explanation on how this happens?
No, that isn't what I said and is a totally different and much simpler situation because the nitrogen is boiling, not freezing and the temperature is lower, not higher than the ice temp.mfb said:Not necessarily. Put a cube of ice from the freezer in liquid nitrogen. Do you expect the nitrogen to freeze?
Iàm sorry, but I donàt see how that can be a general statement. What assumptions are you making here?russ_watters said:Actually, that isn't true(you aren't the only one who said it...): they meet at the freezing temperature of the liquid, regardless of either's starting temperature.
I'm pretty sure both of those are impossible (unstable). Could you please detail the conditions that could cause them?mfb said:It is an interesting situation if the two phases are not the same material. We can have several different options, if we neglect mixing of the substances:
If the freezing point of the liquid is below the freezing point of the solid:
...
- nothing melts, nothing freezes, the final temperature is between the freezing/melting points
- nothing freezes, something melts, the final temperature is at the melting point of the solid
If you have solid steel and liquid water, the steel stays solid and the water stays liquid. Nothing freezes. Nothing melts.russ_watters said:I'm pretty sure both of those are impossible (unstable). Could you please detail the conditions that could cause them?
This thread is about a water/alcohol mixture (perhaps also with sugar) in ice. If there are more complicated/different situations that have different outcomes, I don't thing it is wise to muddle the thread with them, particularly when the OP specifically asked for simplicity.DrClaude said:Iàm sorry, but I donàt see how that can be a general statement. What assumptions are you making here?
Even then, I don't see why you say temperature is not a factor. If the initial temperature of the ice is low enough, you can end up with the liquid freezing completely and the final mixture ending up below the freezing point of the liquid.russ_watters said:This thread is about a water/alcohol mixture (perhaps also with sugar) in ice. If there are more complicated/different situations that have different outcomes, I don't thing it is wise to muddle the thread with them, particularly when the OP specifically asked for simplicity.
Jeez, seriously!Bystander said:No one's made ice cream?!
Only if you have a really bad bartender.DrClaude said:Even then, I don't see why you say temperature is not a factor. If the initial temperature of the ice is low enough, you can end up with the liquid freezing completely and the final mixture ending up below the freezing point of the liquid.
Ok, fair enough. And that's assumptions/a situation far outside the scope of the OP's question. I submit that by expanding the issue so much before he has an understanding of the situation he's asking about (particularly when simplicity was requested), that makes reaching an understanding of that situation less likely.jbriggs444 said:If you have solid steel and liquid water, the steel stays solid and the water stays liquid. Nothing freezes. Nothing melts.
The steel/water example is just an extreme one, the ice/drink setup has the same properties. If ice and drink are at -2C for example, they are in thermal equilibrium (by definition of temperatures). Nothing melts or freezes, assuming the alcohol content is sufficient.russ_watters said:Ok, fair enough. And that's assumptions/a situation far outside the scope of the OP's question. I submit that by expanding the issue so much before he has an understanding of the situation he's asking about (particularly when simplicity was requested), that makes reaching an understanding of that situation less likely.
Agreed, and in the real world that can happen since sometimes people keep their alcohol in the same freezer as their ice. The wording of the question in the title implies that isn't the starting condition.mfb said:If ice and drink are at -2C for example, they are in thermal equilibrium (by definition of temperatures). Nothing melts or freezes, assuming the alcohol content is sufficient.
Correct.ToddSformo said:How about this: freezing is exothermic reaction, latent heat is given off. Melting is an endothermic reaction. So when ice is added to alcohol, it takes energy to melt the ice, and the energy comes from the liquid, in the form of heat, which, in turn, lowers the temperature of the ice-alcohol system?
If both start below zero, yes.mfb said:If the temperature is below zero, no melting happens.
That remains the main issue of the thread and it is not correct.You cannot reach an equilibrium temperature below zero if ice melts (neglecting transient effects from finite heat conductivity and so on)