[paul.fr]

when you make ice cubes from water they are pretty solid, why is it that ice cubes made from cola and other liquids are not as solid?

[chris]

Good question Paul. It's because the cola has substances dissolved in it; this affects the crystal-forming process in two ways:

1) any impurity lowers the freezing point of a solution, and cola contains a very high concentration of sugar, so the freezing point is much lower than water; as such you need to make the solution much colder to make it freeze. Your freezer might not be cold enough.

2) impurities also come between the water molecules, which affects their ability to get close enough to each other in order to form an ice crystal. A crystal comprises lots of molecules stacked together in a very regular fashion. If you have sugar molecules amongst the water molecules the shape of the crystal is affected and it can't form so effectively. You could think of it like a stack of baked bean tins arranged into a pyramid at the supermarket. If you were to try to build the stack with a supply of tins of different sizes it would end up very irregular and not very stable. So it is with ice, and this is exactly how antifreeze works.

Chris

[Karen W.]

I was goingto say sugar as my gran used to add sugar to peaches and freeze them, they would become slusy but not freeze as solid as ice!