A closer look
Gravity is merely a suggestion if you have a loud enough speaker. Acoustic levitation uses perfectly opposed ultrasonic transducers to fire sound waves at each other, creating a standing wave of intense high and low pressure. These pressure nodes become invisible acoustic tweezers that can physically grip and float droplets of water, blood, or hazardous chemicals in mid-air. Chemists are literally using sound to run delicate reactions inside floating orbs of fluid, eliminating the need for glass beakers that might accidentally contaminate the mixture.
