Rimehold: Supercooled Water
Thermodynamics & Statistical Physics arc, page 74 of 193. Back to The Pixelated Physics Universe
Who they are
Rimehold has one line, and says it often: “Supercooled. one speck from panic.”
Rimehold is a character of the Thermodynamics & Statistical Physics arc: drawn in pixels, ruled by one piece of real physics, and never allowed to break it.
The physics
Pure water droplets can stay liquid down to about −38 °C before homogeneous ice nucleation.
$$ \begin{gathered} J = J_0\, e^{-\Delta G^{*}/k_B T} \\ \Delta G^{*} = \frac{16\pi\gamma^{3}}{3\,\Delta g_v^{2}} \end{gathered} $$
| Symbol | Meaning | SI unit |
|---|---|---|
| $J$ | nucleation rate per unit volume | m^{-3}·s^{-1} |
| $J_0$ | kinetic prefactor | m^{-3}·s^{-1} |
| $\Delta G^{*}$ | free-energy barrier for a critical nucleus | J |
| $\gamma$ | ice–water interfacial energy | J/m^2 |
| $\Delta g_v$ | bulk free-energy difference per volume | J/m^3 |
| $k_B$ | Boltzmann constant | J/K |
| $T$ | temperature | K |
Sources
Crossovers
Rimehold meets Sublimora (Triple Point Sublimation). Sublimora skips the liquid phase below 611.657 Pa. Rimehold holds liquid water far below 0 °C without freezing. Phase diagrams say what is stable, and kinetics decides what actually happens.
Rimehold meets Vitressa (Glass Transition). Rimehold keeps water liquid below its freezing point until ice nucleates. Vitressa shows what happens if crystallisation never comes: the liquid slows until it is arrested as a glass.
Rimehold meets Cryo Fault (Ductile-to-Brittle Transition). Rimehold and Cryo Fault both need a trigger. A supercooled drop waits for a nucleation site; a cold steel waits for a crack that grows faster than the metal can flow.
Wear the lore
Concept keywords: Supercooled Water, Rimehold, Thermodynamics & Statistical Physics, physics lore, Pixelated Physics