If you have ever wondered how insects like water striders walk on water or skim the surface of ponds，rivers and oceans，
scientists in the United States have the answer。
Rather than move by creating waves， as some
researchers had thought， the insects use one of their that push them forward at speeds of up to 60inches per second。
Professor John Bush of the Massachusetts Institute of Technology and his colleges。Who
uncovered the secret said that although tiny were created， they were net the main driving force
“The momentum transfer is mainly in the form of subsurface vortices，”Bush said in a report in the science journal Nature。
Water striders， also known as skimmers ， come in hundreds of different species ranging in size from one centimeter （about half an inch ）to the giant Vietnamese variety—20 times bigger and still able to walk on water 。
The researchers uncovered the secret by using high-level tracking and a high-speed video camera that showed the curlicue patterns they made。
They also created a mechanical water，called Robostrider， based on the real thing.