Climbing a slippery slope

How a drop spreads across a solid surface is crucial to many applications in science and engineering. Yet, there is much we still do not understand about this phenomenon. In particular, situations where the edge of the drop moves rapidly across the surface remain obscure. There are two main issues: the effect of inertia and the presence of defects that are always present on ordinary surfaces and hinder the advancement of the liquid. Sartori et al. ( J. Fluid Mech. , vol. 876, 2019) show how these effects can be separated in the case of climbing drops, a phenomenon where drops paradoxically climb an inclined vibrating plate.