Heavy particles Diagram.
(a-b) Heavy particles move towards antinodes of a submerged vibrating plate. (c-d) Single particles and (e-f) a swarm of particles move on pre-defined trajectories on the plate by playing carefully chosen musical notes. (Image: Kourosh Latifi)

Researchers at Aalto University have discovered a surprising phenomenon that changes how we think about how sound can move particles. Their experiment is based on an experiment in which particles move on a vibrating surface. It showed that when a plate is vibrating at a frequency, heavy particles move towards the regions with less vibration; however, the new phenomenon shows how heavy particles move towards the regions with more vibrations.

Many procedures in microsystem assembly require the ability to move and manipulate small particles easily. The method can also inspire future factory-on-a-chip systems.