Scientists Levitate Small Animals
Pastor Dale Morgan
Scientists Levitate Small Animals*
Dec 01, 2006 8:41 AM
By Charles Q. Choi
Special to LiveScience
Scientists have now levitated small live animals using sounds that are,
well, uplifting.
In the past, researchers at Northwestern Polytechnical University in
Xi'an, China, used ultrasound fields to successfully levitate globs of
the heaviest solid and liquid—iridium and mercury, respectively. The aim
of their work is to learn how to manufacture everything from
pharmaceuticals to alloys without the aid of containers. At times
compounds are too corrosive for containers to hold, or they react with
containers in other undesirable ways.
"An interesting question is, 'What will happen if a living animal is put
into the acoustic field?' Will it also be stably levitated?" researcher
Wenjun Xie, a materials physicist at Northwestern Polytechnical
University, told LiveScience.
Xie and his colleagues employed an ultrasound emitter and reflector that
generated a sound pressure field between them. The emitter produced
roughly 20-millimeter-wavelength sounds, meaning it could in theory
levitate objects half that wavelength or less.
After the investigators got the ultrasound field going, they used
tweezers to carefully place animals between the emitter and reflector.
The scientists found they could float ants, beetles, spiders, ladybugs,
bees, tadpoles and fish up to a little more than a third of an inch long
in midair. When they levitated the fish and tadpole, the researchers
added water to the ultrasound field every minute via syringe.
The levitated ant tried crawling in the air and struggled to escape by
rapidly flexing its legs, although it generally failed because its feet
find little purchase in the air. The ladybug tried flying away but also
failed when the field was too strong to break away from.
"We must control the levitation force carefully, because they try to fly
away," Xie said. "An interesting moment was when my colleagues and I had
to catch escaping ladybugs."
The ant and ladybug appeared fine after 30 minutes of levitation,
although the fish did not fare as well, due to the inadequate water
supply, the scientists report.
"Our results may provide some methods or ideas for biology research,"
Xie said. "We have tried to hatch eggs of fish [during] acoustic
levitation."
The research team reported their findings online Nov. 20 in the journal
Applied Physics Letters.