  The spontaneous migration of droplets on conical fibers is studied
experimentally by depositing silicone oil droplets onto conical glass fibers.
Their motion is recorded using optical microscopy and analysed to extract the
relevant geometrical parameters of the system. The speed of the droplet can be
predicted as a function of geometry and the fluid properties using a simple
theoretical model, which balances viscous dissipation against the surface
tension driving force. The experimental data are found to be in good agreement
with the model.
