Robot springs off water

Inspired by water striders, lightweight bots take advantage of surface tension to leap

FLOATING Like a real water strider (left), new robotic insects can rest on water and jump off it.

Seoul National University

July 30, 2015 at 2:00 pm

New robotic insects can hop on water. Researchers from Harvard University and Seoul National University in South Korea studied live water striders, which can skate and leap on water, to design the robots. The bots weigh just 68 milligrams and have bodies that are 2 centimeters long and legs 5 centimeters long.

Like real water striders, the robots use water’s surface tension to support them as they jump, pushing off without puncturing the water’s surface, the scientists report in the July 31 Science.

Both living water striders and the robots have water-repellent legs, which they rotate inward as they leap. This motion provides power to their jump.

The robots can jump on land as well as water. But unlike a living water strider, this first generation of robo-striders can’t get back up after a splash – or crash – landing.