Baking a cake is a fun, but cleaning your kitchen bowls and counters afterwards is a pain. One day, you might perform this culinary chemistry without using your hands or kitchen utensils, thanks to a new gadget from Switzerland that can mix solid and liquid matter in midair.

The device consists of two metal platforms that were facing each other. Each platform was shaped like a cross and was comprised of a series of cubes, made of brass and aluminum. One platform emitted ultrasonic acoustic waves, while the other side served as a reflector.

Liquid droplet suspended in midair. (Credit: Dimos Poulikakos | PNAS)

The researchers found the precise sound frequency needed to suspend a droplet of liquid over a single cube. By adjusting the frequency coming from an adjacent cube, they could move liquid droplet through the air over the platform. Solids could also be moved in this manner.

The experiment started with a simple goal: combine a water droplet with a small piece of sodium (video). Later, the scientists successfully blended instant coffee grounds with water and were able to move larger objects, like a toothpick.

While it would be great to add this tool to the kitchen, its most immediate application would be for chemists trying to mix elements or pharmaceutical drugs without touching them.

Source: Foresti D, Nabavi M, Klingauf M, Ferrari A, Poulikakos D. Acoustophoretic contactless transport and handling of matter in air. PNAS. 2013.