This is just a cool resonance experiment from Ernst Chladni, who was an 18th century German physicist and musician. His important works include research on vibrating plates and the calculation of the speed of sound for different gases.

io9 explains that the particles are arranging themselves along what are called "nodal lines" – narrow curves of motionless calm that criss-cross the otherwise vibrating surface. As the frequency changes, so does the distribution of these nodal lines, which becomes increasingly intricate at higher frequencies.