Science
What makes water behave so unlike other liquids?
- Its molecules stick together
- It has no colour
- It has no taste
The answer is Its molecules stick together. Hydrogen bonds - which is why it climbs, beads, and expands when frozen.
Hydrogen bonds. A water molecule is bent and lopsided - the oxygen pulls the shared electrons towards itself, leaving that end slightly negative and the hydrogen ends slightly positive - so molecules stick to each other far more strongly than their small size would suggest.
Almost every strange thing water does follows from that. It stays liquid over a huge temperature range when a molecule that size ought to be a gas at room temperature. It has an enormous heat capacity, which is why oceans moderate climate and why sweating works. It has high surface tension, which is why insects walk on it. It climbs against gravity in narrow tubes, which is how trees drink. And it expands on freezing, because the crystal lattice holds the molecules further apart than the liquid does.
It is also called the universal solvent, and that lopsidedness is why - charged particles get surrounded and pulled apart by water molecules, which is what dissolving is. Useful for a cell, awkward for a planet: it means rain slowly dissolves rock, and much of what is in the sea got there that way.