Because of the affect that salt is insulating the ice into the vial of water thus making the water freeze
wat do u mean by insulating?
it insulates the water on the outside cold in
I don't understand what insulate means.
This definition from the American Heritage Dictionary will help you understand the meaning of "insulate."
"To prevent the passage of heat, electricity, or sound into or out of, especially by surrounding with a nonconducting material."
wat about da ice cream one??
All of this talk about insulating is nonsense (with no offense to Ms Sue--her contribution was simply defining the word insulate). Salt added to water or ice lowers the freezing point. The normal freezing point for water is 32 degrees F or 0 degrees C. A salt/water/ice mixture will freeze at well below 0 degrees C. That's why salt is poured on the ice in an old-fashioned hand cranked ice cream maker. You want the freezing point to be lower than ice alone because the mixture of milk/sugar/etc freezes at a temperature lower than zero degrees C. If you live in the northern parts of the US you will see salt (and other things are used, also) added to ice and snow on the roadway to make it melt--even in freezing weather. Of course salt is used because it's cheap. It's also corrosive to the underneath of the car and other metal parts of the car. Have you wondered why a cube of ice, frozen solid, melts when salt is poured on it? Simple. Ice lowers the freezing poing of water. That means that zero degrees C is no longer the freezing point--it is lower--therefore, the ice must melt. Where does it get the energy to melt? (Heat must be ADDED to ice to melt it. So the heat that is in the ice goes to melt it, but taking heat away from the ice means lowering the temperature.) I hope this helps.
Thank you, DrBob, for clarifying this.