This is another in my ongoing experiments to make clear ice. So far, I've tried comparing:
Someone in the comments mentioned hearing that carbonated water would freeze more clearly than still water. As most of the cloudiness in ice appears to come from trapped oxygen, this didn't make sense to me, but I figured it couldn't hurt to try.
I froze equal amounts of still water and carbonated water and this is how they came out:
The carbonated water is on the right, and it sure as heck isn't clear. It's got kind of a fun texture with lots of air bubbles in it, but that doesn't get us anywhere for the purposes of this experiment.
Conclusion: Carbonated water does not make clearer ice than still water.