Water is not normal! It does not shrink while cooling down, like any other reasonable liquid would. It actually expands. It sounds crazy, but it’s a fact.

And despite all irrationality, this has many perks: It is why ice floats on top of the water instead of dropping to the bottom of the ocean. Fish and other creatures can then get comfortable in the warmer waters underneath the ice.

Granted, the story of Titanic and the iceberg was not all that great, but sea captains need to watch out properly! Also, you should not leave water bottles inside your car during winter, because frozen water will easily burst the most robust bottle. Then you have a mess!

Nevertheless, it is a good thing that water “swims against the current”: Otherwise, there would be neither climate nor weather nor humans – having emerged from the seas many thousand years ago. And no one would have been here to tell this little story. That would not be ok.