US-China team harnesses bubble-popping energy for robot launch
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The method works by rapidly heating light-absorbing materials with a laser, causing water droplets on the surface around the material to boil, triggering the formation of vapour bubbles.
Once these bubbles grow to a certain point, they suddenly collapse – rapidly releasing energy and creating a strong force that can launch millimetre-scale jumpers 1.5 metres (5 feet) into the air.
By controlling the flow of light, scientists can change how and where these jumpers launch from a wet surface and can even get the small pieces of material to swim in water.
“Our study demonstrates that cavitation can serve as an efficient launching mechanism,” the team said in a paper published in the peer-reviewed journal Science on August 28.
Cavitation is the development and subsequent violent collapse of vapour bubbles that form in regions of a liquid that experience low pressure or high temperature.