Watch the video.
But maybe you’re wondering what’s going on. Well, it seems researchers at the Argonne National Laboratory outside Chicago are looking into ways of developing more efficient drugs. Specifically, they want to make more precisely calibrated drugs that would still deliver their therapeutic benefits while requiring less of the drug being taken. As part of this process, they have to evaporate the solvent that contains the active molecules while avoiding these taking up a crystalline form, as this yields a less efficient product. But if they mix the ingredients in a regular vessel (like a beaker), crystals are much more likely to form during the evaporation process (think of snowflake crystals forming only around dust particles). So they turned to “to an acoustic levitator, a piece of equipment originally developed for NASA to simulate microgravity conditions.”
Two small speakers to generate sound waves at frequencies slightly above the audible range – roughly 22 kilohertz. When the top and bottom speakers are precisely aligned, they create two sets of sound waves that perfectly interfere with each other, setting up a phenomenon known as a standing wave.
At certain points along a standing wave, known as nodes, there is no net transfer of energy at all. Because the acoustic pressure from the sound waves is sufficient to cancel the effect of gravity, light objects are able to levitate when placed at the nodes.
Crystals form when touching a surface? No problem: let’s get rid of the surface! Clearly you can only do this to small amounts at a time, so it’s more of an analytical tool than one intended to be used in mass production.