the.com/phase diagram
A map of a substance's mood swings, charted by pressure and temperature.
means A chart showing which physical state a substance settles into—solid, liquid, gas, or beyond—at any given combination of temperature and pressure.
from 'Phase' traces back to Greek 'phasis' (an appearance or showing, related to the phases of the moon), borrowed into 19th-century science to mean a distinct physical state of matter. 'Diagram' comes from Greek 'diagramma'—'that which is marked out by lines'—from 'diagraphein,' to mark out or delineate. The two fused in the language of physical chemistry as scientists like Josiah Willard Gibbs and others mapped how substances shift between states, giving the humble line-drawing a job: tracing the borders where matter changes its mind.
- triple point
- where solid, liquid, gas coexist in truce
- critical point
- past it, liquid and gas stop differing
- water's weirdness
- ice melts under pressure, unlike almost everything else
- used in
- metallurgy, cooking, climate models, cocktail chemistry