Researchers at Argonne National Laboratory are developing an acoustic levitator that can suspend droplets of liquid in mid-air (video). Speakers at the top and bottom of the device create sound waves that interfere with each other, causing a standing wave. Droplets can be suspended along this standing wave. Researchers are using the device to analyze and develop pharmaceuticals without the need for a container (a container can cause unwanted changes in pharmaceuticals).
photo by Dan Harris/courtesy Argonne National Laboratory, video via Argonne National Laboratory