Researchers used a 3D printer to create a glass microfluidic device to generate vortices. (Simon Haward)

A vortex in the atmosphere can churn with enough power to create a typhoon. But more subtle vortices form constantly in nature. Many of them are too small to be seen with the naked eye. Researchers at the Okinawa Institute of Science and Technology Graduate University (OIST) created a way to examine these small-scale whirlpools with the aid of a device specially developed for this purpose.

Using a 3D printed “microfluidic” device — a small block of glass containing a pair of microscopic crossing channels not much wider than a human hair — the scientists were able to create a vortex that could be readily examined under a microscope. They found that the addition of just one part per million of polymer helped the fluid to flow more smoothly.