Levitation Technology #shorts

Small pieces of styrofoam become trapped between areas of higher pressure induced by high frequency sound waves. Ultrasonic transducers placed at the top and bottom are basically speakers that emit sound waves at a frequency of 43,000 Hz, which corresponds to a wavelength of 8mm for dry air. If the transducers are positioned just right standing waves are produce with nodes of low pressure at half wavelength intervals- and low mass objects like these foam pellets will be suspended against gravity when placed near one of these nodes. Here we see a stack of three pellets with a spacing of about 4mm which is the expected distribution of the nodes. To place the pellets into the sound stream without disrupting the standing waves this device comes with a small screen with a handle which allows the sound waves to flow through the holes in the mesh and trap piece of foam. Although the device uses sound it appears silent as the frequency used is way above that which humans can hear (20Hz to 20kHz).