Water-walking Robot Helps Solve Insect
Puzzle
Dwayne Hunter
Betterhumans Staff
Friday, August 08, 2003, 1:35:46 PM
CT
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John Bush, David Hu and
Brian Chan |
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Postbug: A water
strider meets its robotic
counterpart |
A robotic insect that walks on water like
a water strider has helped researchers understand how the bugs
propel themselves across the surface of ponds and lakes.
A team of scientists from the Massachusetts Institute of
Technology has developed a robotic version of the water
strider that captures the essence of the organism's
movement.
The team was trying to test how water
striders move across the surface of water, as previous
theories incorrectly predicted that young water striders would
be too weak to move.
Caught on camera
Surface tension explains how striders can
stay on the water's surface without sinking, but only careful
experimental study led to an explanation of how they move.
"What we did was to apply some
conventional techniques of flow visualization in fluid
dynamics," MIT's John Bush told BBC News Online.
"You basically sprinkle dye or tiny
particles into the water and record what happens with a
high-speed camera," he says.
Row, row, row your bot
Bush and his team soon found from video
recordings that water striders cause telltale hemispherical
vortices when they move.
These suggest that the striders row
across the water's surface without penetrating it.
This insight guided the team to construct
a self-contained mechanical water strider that moves in a
similar way to its natural counterpart.
The robotic version is much bigger and
less graceful, but still captures the essence of the natural
phenomenon.
The team's work was reported in the
journal Nature (read
abstract). | 
