Why do puddles stop spreading?
Simple everyday phenomenon was unexplained by physics — until now
It turns out that the problem is one of scale, he says: It’s only at the molecular level that the forces responsible for stopping the flow begin to show up. And even though these forces are minuscule, their effect changes how the liquid behaves in a way that is obvious at a much larger scale.
Dear Bog, these guys were still using a “perfect fluid” model to depict a decidedly imperfect fluid. I bet they moonlight building climate models, too.