An international team of engineers is a winner of the 2025 Gizmodo Science Fair for creating an atmospheric water harvesting device that could improve access to potable water in the most remote, arid regions of the world.
The question
Can we pull water out of thin air, even in the driest places on Earth?
The results
Engineers led by Xuanhe Zhao, a professor of mechanical engineering and civil and environmental engineering at the Massachusetts Institute of Technology (MIT), created an atmospheric water harvesting “window” (AWHW) that produces clean drinking water in extremely resource-limited conditions. It’s compact, completely self-sustainable, and only requires one input: sunlight.
“I invent soft materials to solve hard problems for the world,” Zhao told Gizmodo.
The core water-harvesting component of the AWHW is a hydrogel. This material is made from a hydrophilic polymer network and enriched with hygroscopic salts that readily absorb water from the air. It looks a bit like black bubble wrap, with small domed structures that swell when saturated, then shrink back down as they dry out. That swelling-shrinking transformation, inspired by origami, maximizes the material’s efficiency, Zhao said.
The next step was to design a chamber that captures the water collected by the hydrogel. They initially attempted to build a pyramid-shaped chamber, but this resulted in a large footprint for the device and sacrificed efficiency. So, Zhao asked his team, what would the simplest possible design look like?
The engineers ultimately sandwiched the hydrogel between two glass sheets coated with a cooling layer to create a black, window-sized vertical panel. When this panel is placed outside overnight, the hydrogel soaks up water vapor as temperatures drop and humidity rises. During the day, sunlight heats the gel and causes the captured water to evaporate, condense onto the glass, and then trickle down the panels and out through a tube for collection.
“This window-like design turns out to be very effective,” Zhao said.
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