Researchers at MIT have solved the mystery of how the insects known as water striders move across water’s surface. While it is no mystery how they manage to stay afloat (many of us have surely done experiments with water’s surface tension), previous theories on how they manage to move on the surface have proven wrong. The striders actually “row” on the water surface and the researchers have made a very simple robot that mimickes this behavior.

Graduate students David Hu (mathematics) and Brian Chan (mechanical engineering) at MIT solved the riddle by carefully studying water striders’ motion and built the robot out of a 7-up can, stainless steel and an elastic band. It is not quite as elegant as its biological role model that can move at a speed of up to 1.50 m/sec, but nevertheless proves the theory in practice.

I can’t quickly think of any other machine that makes use of water’s surface tension (comments welcomed), but this could lead the way. Maybe successive water strider robots will be used to clean leaves and other dirt from swimming pools or simply make fun toys.

Links:
Article in MIT News (don’t miss the beautiful images and the videos)
Infographic from Nature magazine
The Nature article
Discussion on Slashdot
Purcell’s swimmer (another project in the same lab at MIT)