Particles trapped between two rough surfaces generate friction between them.
Totally Internally Reflected (TIR) light within a glass plate highlights the contact points of a rough rubber sample.
Colliding underwater vortices produce exquisite ordered patterns and turbulence.
A laser sheet reveals the collective behavior of bacterial cells underneath a liquid-air biofilm.
A close-up of a fluorescently-tagged bacterial biofilm shows red motile cells swimming along highways of green matrix cells.
