H2O it's a complicated, three-dimensional, charged object. And one can pack these things in many different ways, a little like playing the child's game of jacks, where those complicated little objects can be thrown together in all different ways.
Ira FlatowI think the most remarkable thing about ice, in my opinion at least, is that it occurs in many, many, many different forms. Most solids occur in typically one or maybe two or three different forms, and ice has approximately 15 different crystal forms, as well as two forms that are called amorphous, which means without any shape at all.
Ira Flatow