Levitation Without Yoga

Materials physicists at China’s Northwestern Polytechnical University have succeeded in levitating small animals with the force of sound. Ants, ladybugs, tadpoles, and fish fry were trapped in midair for a full half hour, buoyed by extremely high-­frequency, high-intensity sound waves. The trick depends on creating a standing wave with regions of low and high pressure. The animals get caught in the areas where pressure is the lowest. Levitation of larger animals, even humans, is not inconceivable but would require wavelengths twice the size of the animal and a levitating machine a couple of stories high. The physicists perfected their pint-size device while working on techniques for “containerless processing”—a way to research and manufacture liquids that otherwise would chemically react with the test tubes.