Most materials get their properties – how hard, or shiny, or what color they are – from what they're made of, but metamaterials gain their properties from their meticulously designed structures, consisting of small components. The shape, size, and arrangement of these small components lets them manipulate electromagnetic waves, improving things like sound insulation, electricity generators, or even invisibility cloaks or ultrasonic levitation surfaces.

or the new study, researchers at Harvard's School of Engineering and Applied Sciences (SEAS) set out to apply that principle to liquids instead.