Scientists have successfully used sound waves before to levitate small objects long time ago, however, a new study have discovered a way to make these objects move midair.
Dimos Poulikakos, lead author of the study and chair of thermodynamics at the Swiss Federal Institute of Technology in Zurich, Switzerland, and his colleagues performed a number of midair experiments using different objects such as water droplets, chemical solutions, coffee, and even DNA and cells. They tried to mix different objects with each other while they were midair such as inserting a DNA in a cell. They also tested if the sound waves would be powerful enough to levitate a toothpick and make it rotate in different directions.
The researchers believe that this new discovery in acoustic levitation will allow scientists to conduct more research using this method which could possibly benefit the pharmaceutical and manufacturing industry.
Poulikakos explained in the report that the intense sound waves were able to do move objects midair counteracting the effects of gravity. They used about 160 decibels during their experiments which is much louder than a launching rocket sound. This intense sound would damage a human’s eardrum but by adjusting its frequency to about 24,000 hertz (Hz), similar to a dog whistle, they were able to work unprotected without damaging their ears.
The scientists designed a levitation device which looks like a chessboard because of its numerous squares. Each square can produce its own sound wave. Above the squares, in its center, a large transparent plastic plate is responsible for reflecting the sound waves.
During the experiments, the scientists encountered problems such as how to move the objects without breaking them and balancing the sound waves emitted by each square. They were able to resolve the issue by using computer software which will balance the sound waves each square will produce.
The study was published on the online journal PNAS.
