Why does acoustic cavitation in water fail far below quartz-inclusion strength?
In plain words
Water stretched by sound waves breaks at about minus 300 atmospheres, but tiny drops of water sealed inside quartz crystals survive about minus 1400 atmospheres. Either the sound experiments are spoiled by something not yet identified, or the textbook theory of how bubbles form is wrong for water.
Precise statement
Dynamic methods (focused ultrasound, shock reflection, centrifugation) give reproducible room-temperature cavitation pressures $P_{\mathrm{cav}} \sim -2.6\mathrm{e}8 \text{ to } -3.3\mathrm{e}8\,\mathrm{dyn}/\mathrm{cm}^{2}$ (about $-0.3\,\mathrm{kbar}$), while isochoric cooling of micrometer quartz inclusions reaches about $-1.4\mathrm{e}9\,\mathrm{dyn}/\mathrm{cm}^{2}$ ($-1.4\,\mathrm{kbar}$), close to classical nucleation theory with the bulk surface tension. Identify the mechanism that sets the acoustic value (an unidentified impurity or heterogeneous nucleation, a curvature-dependent surface tension, an equation-of-state anomaly tied to a liquid-liquid critical point, or a flaw in the inclusion experiments) and show that it reproduces the measured $P_{\mathrm{cav}}(T)$ of each method over the temperature range in which that method has data.
What would settle it
An acoustic or inclusion experiment on water of controlled purity that moves $P_{cav}$ continuously between the two values by varying a single identified parameter, or a simulation that reproduces both values from one model.
Status in the literature
Unverified note
Molecular simulations with curvature-corrected nucleation theory (2016) agree with the inclusion value near -1.4 kbar, so the lower acoustic value is the unexplained one; no accepted mechanism as of 2026 (not re-verified for 2024-2026).