An improved version of a technique for folding tiny objects from a thin membrane uses a magnetic field to affect the shape. The membrane wraps around a droplet of fluid that distorts in response to the field.
Phys. Rev. Focus28, 7 (2011) – Published August 12, 2011
A rapidly expanding and collapsing microbubble in a fluid exerts forces strong enough to roll submerged particles stuck to a solid surface, which may explain how ultrasonic cleaning of jewelry and silicon wafers in a liquid removes dirt.