Now this is a strange effect. This stunning video shows a tiny drop of silicone oil that's perpetually bouncing on a bath consisting of the same fluid. A new study provides an explanation — and it's a phenomenon previously thought to be exclusive to the quantum realm.
It's called a pilot-wave system, and it was an idea that was first proposed by Louis de Broglie in 1926 to describe the motion of quantum particles, namely electrons that move in resonance to a corresponding guiding wave.
In this case, a version of pilot-wave dynamics has been observed at the macro scale. In this video — the product of work done by scientists the Technicla University of Denmark and MIT — a bath of silicon oil is vibrating in such a way that the waves produced during the collision allow the droplet maintain its cohesion and either bounce or skim across the surface. The drop achieves resonance with its wave field when the vibration amplitude is increased, allowing it to be propelled along the bath surface.
Here are some more examples of how the droplet can be made to interact with the bath depending on the characteristics of the wave field.
Super interesting! As an aside, this is a different effect than the coalescence cascade, which is what happens when a layer of air trapped beneath the droplet prevents it from immediately coalescing into the pool. It's also a study that reminds me a bit of this: Ferrofluids that dance and multiply over a water-repelling surface.