Fed Up With Tabletop Puddles, Scientists Engineer a High-Tech Dripless Teapot

We've all experienced the fluid-dynamics phenomenon known as
the "teapot effect." Every time you pour out a nice relaxing
cup of tea, a little of the elixir dribbles down the outside
of the spout of the teapot, dampening your doily and your
spirits.

It happens because liquid clings to the lip of the spout
instead of exiting neatly, especially at low rates of flow.

Cyril Duez and his team of fluid dynamicists could not
tolerate one more dribble. They have identified the root
cause, a "hydro-capillary effect" that makes the tea fail to
leave the spout material gracefully. Two techniques can be
used to combat this.

One is to simply use a spout made of thinner material, which
gives the wayward beverage less purchase. Metal teapots, for
instance, like we see at Chinese restaurants, tend to drip
less than pudgy-walled ceramic ones.

The other, cooler approach is to coat the spout with one of
a class of super-hydrophobic materials, which repel any
attempt by the tea to cling to the spout instead of going
where it's supposed to. Some of these materials can be
activated and deactivated electrically, raising the exciting
possibility, as Technology Review points out, of a hilarious
gag teapot with a drip/no-drip switch. It would go nicely
with your Fraunhofer Perfect Mug.

The puzzling part is that the team of exacting tea scientists
are not British, but French.