The world's most precise water costs $120,000 a gallon
Standardized in Vienna in 1966, VSMOW defined the kelvin until 2019 and still calibrates precision thermometers.

A 5-milliliter ampoule of the world's most precise water sells for $159 — about $120,000 a gallon, Signore Galilei writes. It is Vienna Standard Mean Ocean Water (VSMOW), and labs buy it because water's freezing point varies based on its e…


