The Complicated Physics of a Dribbling Teapot (via Neatorama)

When flow from a teapot (or a liquor bottle) is very slow, the liquid has a propensity to dribble back along the surface of the spout.

“Previous studies have shown that a number of factors affect [dribbling], such as the radius of curvature of the teapot lip, the speed of the flow and the “wettability” of the teapot material. But a full understanding of what’s going on has so far eluded scientists…”

Now scientists at the University of Lyon have identified a “hydro-capillary” effect that can be overcome either by thinning the edge of the spout, or by applying superhydrophobic materials to the lip.� Superhydrophobicity is sometimes referred to as the “Lotus effect,” because the leaves of the lotus and certain other plants (and the wings of some insects) are among the most water-repellant surfaces known to science.

Further details about the “Teapot effect” are available at M.I.T.’s Technology Review, via the New Shelton wet/dry.