Something that might interest people.
It looks like “Harry Potter” magic, but it’s just acoustic levitation: Researchers have created a device that uses sound waves to make liquid droplets and small solid objects float in the air and merge into each other on command.
The ultrasonic chessboard could someday be used for delicate chemical or pharmaceutical processes where contamination from a surface could spoil the reaction, said Dimos Poulikakos, an engineer at Switzerland’s ETH Zurich. Poulikakos is the senior author of a paper on the project appearing in the Proceedings of the National Academy of Sciences.
“Levitation is an old story,” Poulikakos told NBC News. “It was really discovered 100 years ago.”
What’s new about the device that he and his colleagues constructed is that it uses a chessboard-like array of levitating devices to transport objects through the air with ultrasound. The research team made droplets of water and hydrocarbons float around the squares of the array and smash into each other.
Image: Levitating toothpick
ETH Zurich via PNAS
A wooden toothpick is seen from above as it levitates over ETH Zurich’s ultrasonic chessboard. The sound waves can be manipulated to make the toothpick twirl in place, as seen in this video: http://bit.ly/18Z8iOR
Poulikakos said the method also worked on bits of instant coffee, a bubbling fleck of sodium, tiny steel balls and a wooden toothpick (which looked as if it were slowly twirled by an occult hand).
Surfing the wave
Each of the squares in the chessboard is an acoustic resonator, sending out sound waves at 24.3 kilohertz so that it’s reflected off a precisely placed sheet of transparent plastic. The frequency is too high to be heard by human ears. But even at that frequency, the acoustic interference can be strong enough to create a standing wave between the resonators and the reflector, counteracting gravity’s pull on the target object.
Rest Here