One Thing We Do Know All About Is Water ... Right?

One of the things you'd think we'd have figured out by now is water since it plays such a fundamental role in life on this planet and since humans have been studying it for ... well, forever. For example, the philosopher Thales (620 BCE - 546 BCE) said that water is the Primary Principle. In the Timaeus, Plato's (427 - 347 BCE) major cosmological dialogue, the Platonic solid associated with water is the icosahedron which is formed from twenty equilateral triangles. This makes water the element with the greatest number of sides, which Plato regarded as appropriate because water flows out of one's hand when picked up, as if it is made of tiny little balls (from Wikipedia). Somewhat more recently we have: Researchers explore ubiquitous interaction of biomolecules with water (February, 2017), Antigravity water transport system inspired by trees (July, 2019) plus Breakthrough discovery reveals how thirsty trees pull water to their canopies (January, 2016), and Water Flow Helps Cells Move (May, 2015). So perhaps you'd be surprised to see such articles as Fast x-ray scattering reveals water's two liquid phases (November, 2020) or Second critical point appears in two models of water (August, 2020) where it is written, "The central role of water in life as we know it makes it easy to forget just how unusual it is. Unlike most other liquids, water is denser at ambient pressure than the ice it forms when it freezes. It also exhibits negative thermal expansion (meaning that it expands on cooling, rather than contracting), becomes less viscous when compressed and boasts no fewer than 17 crystalline phases." There's also:

where it appears that water is much more complicated than we'd naively thought.

For more articles on research of and about water (with some stuff about fluids in general) have a look at Stuff about Water.

Speaking of water in its frozen form (weren't we?), check out icicles where I've gathered some articles about the "Ice Atlas" put together by Professor Stephen Morris (we were graduate students together at the University of Toronto a long time ago!). The Ice Atlas contains some 230,000 images of icicles in various states of evolution. This is a serious subject of research since little is known about icicle formation. For a technical discussion see On the origin and evolution of icicle ripples by A.S. Chen and S.W. Morris (September, 2013).