A drop falling from a faucet is a common example of a mass fissioning
into two or more pieces. The shape of the liquid in this situation has
been investigated by both experiment and computer simulation. As the
viscosity of the liquid is varied, the shape of the drop changes drama
tically. Near the point of breakup, viscous drops develop long necks t
hat then spawn a series of smaller necks with ever thinner diameters.
Simulations indicate that this repeated formation of necks can proceed
ad infinitum whenever a small but finite amount of noise is present i
n the experiment. In this situation, the dynamical singularity occurri
ng when a drop fissions is characterized by a rough interface.