Sound doesn’t just help us hear music or communicate underwater—it can also be used to move objects without physically touching them.
Thanks to new research from the University of Wisconsin-Madison, scientists have developed a special material that allows them to control the movement of floating or submerged objects using only sound waves.
Dajun Zhang, a Ph.D. student leading the research, presented his findings at a major international acoustics conference on May 20.
He created a new type of “metamaterial,” which is a man-made material designed to behave in unique ways because of its special structure.
In this case, Zhang’s metamaterial has a tiny sawtooth pattern on its surface. When sound waves hit this surface, they bounce off in controlled ways, allowing nearby speakers to push and pull the material in very specific directions.
By attaching this metamaterial to different objects—such as pieces of wood, wax, or plastic foam—Zhang was able to use sound waves to move them around in water. He could push, pull, and even rotate the objects.
In tests with submerged items, the sound-controlled movement worked in three dimensions, giving him precise control over where the objects moved and how they turned.
This kind of touch-free manipulation has big potential. It could make underwater work much easier, such as positioning parts for robots or assembling items underwater.
Even more exciting, since the human body is mostly water, this technique could eventually be used for medical applications like remote surgery or delivering medicine to exact spots in the body—without the need for invasive procedures.
Creating materials with the right properties for this kind of work is usually expensive and complex, but Zhang developed a new way to make the metamaterial that is both low-cost and highly precise. His method also creates the right acoustic contrast needed for the sound waves to work effectively in water.
Zhang is now working on a smaller, more flexible version of his material—something like a patch that could be used inside the body or on underwater robots. He believes this innovation opens the door to a wide range of future technologies, including new tools for medicine and ocean exploration.
“This is just the beginning,” Zhang said. “Our material shows that we can now use sound to move things remotely, both underwater and potentially inside the body.”
