Does the type of ice even matter?

Unlike what many people believe, Mars is actually very similar to Earth. Mars also have polar ice caps, which get bigger and smaller in accordance to the seasons. These seasonal polar caps are made from the martian air that freezes during the winter. They are made out of frozen carbon dioxide, or "dry ice." So why are these caps made out of carbon dioxide? Why not water?

Answering this question seems very simple. For one thing, the atmosphere of Mars is 95 percent carbon dioxide. That means that when the air freezes during the winter, the gaseous carbon dioxide is converted in solid carbon dioxide and stored in the polar caps. Depending on the time of year, more than a quarter of the atmosphere can be found frozen on the ground in these caps. 

But is that really the only answer? We can dive a little deeper into chemistry to fully answer this question. 

Carbon dioxide has a low boiling point. This is because the only intermolecular force in carbon dioxide is London Dispersion Forces, or LDF. It does not have dipole dipole interactions because of the structure's symmetry, nor hydrogen bonding, because it is a nonpolar molecule. Therefore, it does not require much energy to separate carbon dioxide molecules from the solid state to gas state. It would take low amounts of energy and low temperatures to have dry ice, and these measurements are found conveniently on Mars.

Maybe you already knew that carbon dioxide has only low LDF. But did you ever think to connect that simple idea to the polar ice cap cycle existing on Mars? These simple connections can easily be made, if you just look for them throughout the universe.