Researching are using sound waves to levitate and move hovering cells, DNA, toothpicks, water droplets, and other small bits of material in different directions. Eventually, the technique could be used for a "lab on a chip" or to transport hazardous or sensitive chemicals or biological materials in the laboratory. Watch the explosion above when sodium and a water droplet collide! ETH Zurich mechanical engineer Dimos Poulikakos and his colleagues reported their results in the new Proceedings of the National Academy of Sciences. From Science News:
To achieve levitation, Poulikakos and colleagues vibrate aluminum blocks about the size of postage stamps up and down, like tiny jackhammers. The rapid buzz kicks up sound waves that sail upward until they hit a Plexiglas reflector and then bounce back down to the blocks.
When these falling waves run into the climbing ones, they can cancel out, creating a low-pressure pocket that can support an object's weight.
By adjusting vibration rates to control the position of the pocket, the researchers could float particles across a chessboard of the aluminum blocks.