Why does water roll off a duck's back but spread on clean glass? For macroscopic (millimeter-scale) drops, this behavior can be explained using continuum theory. However, when nanoscale (10–9 mm) droplets spread on surfaces, a force called line tension becomes relevant and mysteriously changes ...
Source: [Phys.org](https://phys.org/news/2026-06-molecular-simulations-uncover-nanodrops-thin.html)