We’ve all seen devices that can generate drinking water out of thin air, but is it possible for one to work even in the driest of climates? That’s what an international team of engineers set out to accomplish at the 2025 Gizmodo Science Fair, and the result earned them a winning prize.
The team’s ultimate design is compact and self-sustaining, requiring only sunlight and a little time to produce water that is immediately safe to drink. It works thanks to a hydrogel made from a hydrophilic polymer network and containing hygroscopic salts, which absorb water from the air. The gel forms multiple small domes that swell as they gather water and shrink when it’s expelled, making it look kind of like a sheet of black bubble wrap.
This hydrogel is placed between two sheets of glass and situated upright like a window. During the night when temperatures drop and humidity increases, the hydrogel collects the water vapor in the air. Then during the day, the sun hits the window and heats it, causing the stored water to evaporate and form condensation on the glass. A tube at the bottom of the panels collects the condensation as it trickles down. During a one-week test in Death Valley, the driest location in the U.S. where the humidity fluctuated between 21 percent to 88 percent, the window collected up to two-thirds of a cup of water per day.
