I love ice, when I was in Antarctica many decades ago, I got to see a lot of ice. And the one thing that impressed me -because I love to talk about ice - is that it has a color.

I love ice, when I was in Antarctica many decades ago, I got to see a lot of ice. And the one thing that impressed me -because I love to talk about ice - is that it has a color.

The different colors [of water] again refer to the fact that those little jacks, if you want to call them jacks, those little pyramids, can be packed together in all different ways. And depending on how they're packed together.If you Google blue ice, as I did just while your caller was asking his question, you see some beautiful pictures of ice covering a lake.

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.

Mainly, of course, if you're not an ice climber, where you really need ice, for most people ice is a damn nuisance. And we just can't wait for it to all melt.And it's always a remarkable fact that it takes so long to melt because the temperature of the air can be well above the freezing point, and the ice is still solid there. So for most people, that's the experience.

Amorphous forms [of ice], for example, are found naturally on comets, on asteroids, and the crystalline forms are found on Earth or at least could be made on Earth with enough pressure. Nothing else does this.

Ice is remarkable in many ways. A simple experiment one can do at home is to add salt to an amount of water in different concentrations. For example, one can mimic the concentration of the ocean, or one can make it even saltier.