H Téphany

Long Lifetime Floating Drops

Using a rotating magnet device, we observe the noncoalescence of droplets of certain liquids slightly put in contact with the surface of the same liquid. The droplets go into the vortex and coalesce, the resulting drop staying in equilibrium in this position. If the rotation of the liquid is stopped, the drop rests at the surface for more than 20 s, as if it were immiscible, without any relative motion.