When a drop falls on a liquid film, its impact drives a thin liquid sheet called the ejecta upward and outward from the point of impact. Within milliseconds, tiny perturbations develop in the ejecta and begin growing exponentially. These become the distinctive spikes of the crown. The momentum from the impact drives the ejecta and spikes further outward until it overcomes surface tension’s ability to hold the liquid crown together. Tiny droplets escape the crown before the ejecta comes crashing down. The whole process takes only a few hundred milliseconds from start to finish. (Photo credit: S. Jung et al.)
Momentary Crown
