We’ve all seen videos of glass shattering as an extremely loud, high-pitched noise plays in the background, but did you know that the same sound could also cause objects to levitate? Not only this, scientists have also been experimenting with this phenomenon to see if, in the future, we would be able to levitate humans. The phenomenon has been named ‘acoustic levitation’ and may have numerous applications, especially in the field of biology.
A levitator often has two parts – one that generates the sound, and one that reflects it. These are called the transducer and reflector. When the sound wave reflects, its compressions meet its rarefactions and create interference. This interference can merge with the reflected wave to cause a standing wave. Standing waves are waves which have points called ‘nodes’ that remain stationary while the rest of the wave is in motion. If an object is able to rest in a node, it will stay motionless in mid-air, levitating.
Acoustic levitation is currently being used in numerous ways. The phenomenon creates a zero-gravity environment that can be used to optimize cell growth. Surgeons can now use this technology to shape cartilage cells so they can perfectly replace a patient’s missing or damaged tissue.