Surfing on Acoustic Waves

(ETH Zurich, July 16, 2013)

ETH researchers are able to make objects fly in mid-air and even rotate a toothpick in the air by letting them ride on acoustic waves. This is not simply an amusing trick: moving objects such as particles or droplets of a liquid freely in mid-air makes it possible to investigate processes while avoiding any disruptive contact with a surface. For instance, some chemical reactions and biological processes are compromised by surfaces, and certain substances disintegrate on contact with a surface. Until now, scientists have been able to generate such a "contact-free" levitational state only with the help of magnets, electrical fields or in liquids with the help of buoyancy, but this limited the selection of materials that can be handled massively.