Above the surface of upwardly sonicated silicone oil, falling droplets of the liquid are suspended by a thin membrane of air, acoustically regenerated underneath each droplet. Without coalescing for extended periods, these palpitating spheroids bounce on the air-oil interface. The repeated impact of a bouncing droplet incites a standing capillary wave that interlocks with the waves of neighboring droplets. This close-range attractive force can result in the orbital motion of droplet pairs and clusters. During more stable modes of excitation, self-organizing geometric rafts emerge in accordance with the closest packing of spheres: the distance between droplets decreases with increasing frequency, leading to dense lattice formation.”

Mucilaginous Omniverse. Evelina Domnitch, Dmitry Gelfand.

(via freshphotons)