Scientists have long been able to levitate small objects, like drops of water or plastic pellets, using only the power of sound. By sandwiching an object between two sets of speakers—or a speaker and a reflector—you can send precise, energetic blasts of ultrasonic noise to trap objects midair. But today, a fascinating new breakthrough can now accomplish this odd feat of levitation with a single array of speakers on just one side. It’s like using sonic tongs with just one side instead of two.
Philip Marston, an acoustic physicist at Washington State University who was not involved in the research, says, “There’s been a long-reaching effort for doing these kinds of things with optical laser beams, and now [this research team] has found a relatively inexpensive way to do the same with acoustic sources.”