A step toward harnessing clean energy from falling rainwater

When two materials come into contact, charged entities on their surfaces get a little nudge. This is how rubbing a balloon on the skin creates static electricity. Likewise, water flowing over some surfaces can gain or lose charge. Now, researchers have harnessed the phenomenon to generate electricity from rain-like droplets moving through a tube. They demonstrate a new kind of flow that makes enough power to light 12 LEDs.