Scientists have deisgned a robot that not only walks but can bounce on water.  By using a highly water-repellent sphere, which mimicked the actions of a water strider’s highly water-repellent legs, a team of researchers at Seoul National University were able to determine a small range of speeds at which the sphere or insect could hit the water and not sink.If the sphere hit too fast, it would shoot through the surface of the water. If it hit too slow, it would not bounce back and sink.The water strider is one of the fastest moving insects in the world. It can travel up to 100 times the length of its body in one second, equivalent to around 400 mph in human terms.