A bunch of drips just got their ticket to stardom. Weiyu Ran and colleagues from Clemson University in South Carolina have levitated droplets of water using an ultrasonic field
First the researchers increase the strength of the field, which flattens the floating drops into discs. They then turn the drops into stars by tuning the field to the resonant frequency of the drops – or exact multiples of that frequency. Using a particular multiple produces a star with the corresponding number of spikes.
The starry shapes may look cool but have no known use. However, Ran's team produced them while playing with a set-up that makes drops hover, with the aim of coming up with new ways of removing particles from air. In mines, for example, sprays are commonly used to eliminate dust. However they aren't effective at removing tiny, micrometre-sized particles that are harmful to lungs.
The team's device is too small for such applications – and would need to be scaled up. "Using current techniques would require excessive power so an alternate design would be needed," says team member John Saylor. "It's a proof of concept."
The research will be featured at the American Physical Society's Division of Fluid Dynamics meeting in Pittsburgh, Pennsylvania, next month.
Reference: arxiv:1310.2967
If you would like to reuse any content from New Scientist, either in print or online, please contact the syndication department first for permission. New Scientist does not own rights to photos, but there are a variety of licensing options available for use of articles and graphics we own the copyright to.
Have your say
Only subscribers may leave comments on this article. Please log in.
Only personal subscribers may leave comments on this article
All comments should respect the New Scientist House Rules. If you think a particular comment breaks these rules then please use the "Report" link in that comment to report it to us.
If you are having a technical problem posting a comment, please contact technical support.
