The video above shows a drop of water and a small piece of the element sodium colliding and causing an explosive reaction in midair.
What’s really great? The two particles are suspended there entirely by sound waves, using a new technique that to levitate objects and move them through the air. The research was published July 15 in the journal Proceedings of the National Academy of Sciences.
Scientists had already known how to use sound waves to suspend matter in air, but couldn’t get the objects to move from side to side. While levitating an object, the sound waves would basically create a tunnel around it, keeping it in on place.
Somewhat like a ping-pong ball suspended by the air from a hair dryer, the object suspended by sound waves could only bounce in one place.
“Before, it was like you had a beautiful car, but could only park it,” study researcher Dimon Poulikakos, of ETF Zurich, told Science News. “Now you can drive the car.”
Poulikakos and his team figured out how to bend the sound waves to allow movement.
To levitate the material, they use several small square metal plates that vibrate, with a sheet of plexiglass a few millimeters above them.
When the plates buzz rapidly, the sound waves rise up and bounce off the plexiglass sheet above. The collision of the rising and falling sound waves suspend the the objects perfectly between them.
The researchers found that tiny adjustments to the rate at which each metal block vibrated, they could manipulate the particles to move horizontally.
The breakthrough could make it much easier for scientists and engineers to handle volatile materials (as demonstrated in the video, where the element Sodium combines with water to produce a volatile reaction).
Polystyrene and water:
Instant coffee and water:
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