Temperature-induced change in bubble-size distribution as the cause of sound differences

Establish whether temperature changes the sound of pouring water by altering the size distribution of entrained air bubbles, specifically determining if pouring hot water produces a greater number of larger bubbles than pouring cold water and whether this difference drives the observed acoustic disparity.

Background

Based on qualitative high-speed visual observations, the authors note that hot water tends to produce more and larger bubbles than cold water, which would shift Minnaert resonance to lower frequencies.

They explicitly state a conjecture that temperature influences the pouring sound via its effect on bubble size, linking fluid dynamics to the acoustic spectra reported.