Ultrasound creates an invisible tube that guides liquid through the air

Researchers demonstrated a stream of liquid flowing horizontally in midair inside an invisible ultrasound "tube." A cylinder lined with hundreds of tiny speakers about 5 cm away keeps the stream suspended without contact and without audible sound.

• Liquid flows horizontally through the air without a physical tube
• A cylinder of hundreds of tiny speakers sits about 5 cm away
• The ultrasound is inaudible to humans