Scientists defy gravity with ‘perpetual’ water pump
Scientists have figured out how to pump water upwards in a thick tube using a combination of surface tension and water-repellent materials. Before you get your hopes up, it’s definitely no perpetual-motion machine — but the discovery from Beihang University researchers in China could bring other benefits. Here’s how it works: The right angle pipe shown above is filled with a small amount of water, which can’t drain thanks to a copper mesh doped with a superhydrophobic (water-rejecting) material at the bottom. When a small droplet is introduced, it’s drawn upward by surface tension, albeit very slowly (the above GIF is sped up about 75 times).
Though it seems to violate the first law of thermodynamics, there are some caveats. First off, the system can only “pump” water around a centimeter (half-inch) up before the effect stops working. More importantly, the water must be introduced at the bottom in droplet form (below) by someone squeezing a pipette, for instance (it takes energy to make a droplet). When the droplets collapse via surface tension, enough energy is released to lift the water. That said, the invention could still prove useful. The new technique can lift water up a thicker pipe than capillary action, and the team feels the research could eventually result in new “microfluidic” devices like labs-on-a-chip.
Filed under: Science
Via: New Scientist
Source: Wiley
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