Slushie Science

Most recent answer: 11/10/2012

Q:
Will the different colored slushies affect its freezing point? I wanted to try and test this question in an experiment. However, I wasn't sure about the original science behind making a slushy, and then testing it in this experiment. May you please explain to me why, and how this experiment would take place?
- Nya (age 13)
usa
A:
Here's some background.

 A slushy (or slushie) is a mixture of some crushed ice and some sugary liquid water. It stays slushy for a while even out in a warm room because the ice melts slowly. The main reason is that it takes some heat to melt ice, and heat flows into the slushy slowly. The slushiness actually helps slow the heat flow, since it keeps the water from circulating around. Less importantly, as the ice starts to melt, it dilutes the sugar in the liquid. The more dilute the sugar gets, the higher the melting temperature of the ice goes. So that helps keep the ice from melting more quickly.

You ask what role the color plays. Usually the molecules that cause the color are much less numerous than the sugar molecules. So they play very little role in how fast the slush melts. If one color happens to be sweeter, that would matter some, since sweeter drinks melt at a little lower temperature. We discuss why on several old answers, including .

Mike W.

(published on 11/10/2012)