Shape and instability of free-falling liquid globules

The velocity of a falling raindrop depends on its size, and thus so does its shape. Here we describe the different simple shapes which model drops falling in air. While millimetric drops remain spherical, owing to the action of surface tension, drops larger than the capillary length get flattened, as sessile drops on solids. Air penetrates still larger globules, which are observed to be unstable. They inflate till they burst, generating myriads of fragments.