A can of beer, and some water...?

Question

Heres and experiment, you get 3 cans of beer, three containers, in the first container you put plain cold water, in the second container you put cold water and some ice, in the third container you will place water ice and some salt (as to make the solution salty). Now placing the cans of beer one in each container and leaving it for 15 minutes. Taking out the beer from each container and testing the temperature of each beer. Why is it that the can of beer in the salty water and ice was the coldest?
As in is there a reaction between the ice and salt water that cools the beer the most? or what?

Answer 1

I believe the reason why, is because salt causes freezing point depression, which results in a lower temperature. This is a result of increases in entropy- more molecules moving around hitting each other which results in the ice melting. When the ice starts to melt it undergoes an endothermic reaction (a reaction where the effect is a net decrease in temperature). An exothermic reaction, would be where the temperature would increase.

See the link below for more details...

Answer 2

The temperature of the beer in the can will approach the temperature of the water bath it is in.

If you put ice into the water, the water temperature will become lower, as the ice melts and cools the water. (Heat from the water is used to melt the ice, so the water gets colder.) But pure water cannot cool below 0 C - it will freeze and change into ice - so that's the lowest water temperature you can get with an ice bath.

However, if salt is added to the ice-water mixture, the dissolved ions interfere with the freezing process. It is harder for the water molecules to get together and form a solid - the temperature must go below 0 C before this can happen. The melting ice can take more heat out of the water, and the water temperature drops below 0 C. So, this last water bath will be the coldest, and cool the beer the most.

Cheers !

Answer 3

This experiment was conducted on an episode of Mythbusters. Search the Discovery Channel for the episode. Beer cools the fastest with water, ice, and salt.

Answer 4

Water and some salt (ie amonia salt) creates a drop in tempeature, hence cooling the beer can on top faster.