Water jets may break up into droplets thanks to jiggling molecules

Water streams from faucets break into droplets due to molecular vibrations caused by heat, according to new research by physicists. Through 158 experiments using various nozzles and fluids, scientists discovered that thermal fluctuations—random jiggling of molecules—create tiny disturbances about one-tenth of a nanometer that grow into visible droplets through surface tension effects. This finding explains the mysterious origin of liquid jet breakup, revealing how microscopic molecular movements directly influence everyday phenomena visible at kitchen sinks.