CAMBRIDGE, Mass., Sept. 29 -- Walking
on water is no problem for some bugs. Getting out
can be another story.
An
obstacle that's nearly invisible to humans can be
a life-or-death challenge for a creature the size
of, say, a speck of dust. Two researchers are
studying this dilemma, with an eye toward applying
it to nanotechnology.
Many water-walking insects
can't climb menisci using their traditional means
of propulsion. (Credit: David Hu and John Bush,
Massachusetts Institute of Technology/Nicolle
Rager Fuller, National Science Foundation)
Water-walking insects that can't
climb a "meniscus" -- the crescent-shaped and
barely visible slope literally at water's edge --
must summon the energy to surf the interface
between liquid and solid in ponds and other wet
places in order to escape predators or reproduce.
Menisci are all around us --
for example, the slight upward curve of water in a
glass where it meets the side.
"But we don't notice them
because they're so small, only a few millimeters
in height," said mathematician David Hu of the
Massachusetts Institute of Technology. For
insects, he said, those slopes are like
frictionless, slippery mountains.
Hu and coworker John Bush
have done the math to explain how nearly
weightless insects find the traction to ascend a
wall of water several times their height. Such
obstacles may surround a leaf floating in a stream
or a stone on the riverbank.
According to Bush, the
study, which was funded by the National Science
Foundation, may be of interest to nanotechnology
researchers, "because they, too, are concerned
with problems at very small scales."
For more information, visit:
http://www.photonics.com/clickthru/webclickthru.asp?url=http://www.mit.edu&codivid=mit&placement=News
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