Water science

Water breaks most of the rules its molecular weight predicts. It should be a gas at room temperature, and ice should sink. Almost every anomaly traces to one thing: the molecule is bent.

Almost all the world’s liquid fresh water is underground. It is invisible, slow, and the easiest resource in the world to overdraw without noticing.

A river is a flow, not a store. Understanding discharge, baseflow and the flow duration curve explains almost everything about what a river can and cannot supply.

Solid, liquid and gas — and the transitions between them, which move more energy around the planet than almost anything else.

Frozen water is the world’s largest freshwater store and its most important natural reservoir — releasing water in summer, precisely when it is needed.

Water chemistry is mostly a record of what the water has flowed over. Hardness, pH, alkalinity and mineral content are all set by rock.

Density, viscosity, surface tension, specific heat, conductivity — the numbers, what they mean, and why so many of them are anomalous.