Beetle Boat Runs on Surface Tension

Researchers have made a small boat that doesn’t require oars or pedals to move forward but relies on the energy of the water surface itself.

The mechanism is inspired by the larvae of the beetle Pyrrhalta. A pyrrhalta larva floating on the water propels itself forward by bending its back, releasing surface tension on its head and tail, and creating a capillary thrust that pulls it forward. The two-centimeter-long boat, designed by researchers at the University of Pittsburgh and presented at the MEMS 2009 conference in Sorrento, Italy, this week, uses a low-energy electrode to change the surface tension at its tail end to create propulsion, and another electrode at the front to act as a rudder. It could be powered by a solar panel and developed into a low-maintenance water-quality monitoring device. The video below shows the boat in action; the second half shows the rudder capability.