I suppose that there will be dozens of Ices in this week's I-theme, but never mind: This is my way of doing it. Wikipedia defines Ice like this:
Ice is the name given to any one of the 15 known crystalline solid phases of water. In non-scientific contexts, it usually describes ice Ih, which is the most abundant of these phases. It can appear transparent or an opaque bluish-white color depending on the presence of impurities such as air. The addition of other materials such as soil may further alter appearance.The crystal below ought to fit in nicely here.
As you can see, then, Ice is plain old H2O in a frozen phase. This transition takes place at 0 degrees C, and that is in fact why Celsius decided to start his scale here. In addition, as long as both water and ice are in contact, they both are at 0 degrees. (It is of course unnecessary to mention that boiling water - the next phase transition for water - is at the other end of the scale, at 100 degrees).
There exist many types of ices since ice changes properties when things like pressure and temperature and other variables are changed. Ice XV was mentioned by Wikipedia, but as far as I know, that exists only in theory. The others has been produced.
This getting a bit a bit esoteric, so I'll get on to something that ice can be used for. Skating is of course an obvious choice, but I don't seem to have any proper picture of a skater, so you'll have to settle for another little fellow who can walk on the ice without any artificial support whatsoever.
PS For more about ABC Wednesday, please visit Mrs. Nesbitt's Place. Is well worth the effort.
PPS I'll be away for some days, so it may be some time before I have the opportunity to visit all of you.
PPS If you did not find me registered with Mr. Linky at Mrs. Nsbitt Place - it was because it did not show up! Now closing down.