Scientists have developed a way to pull water out of air in arid settings, powered by nothing more than sunlight. This is a big deal for fighting water scarcity, a problem faced by more than half the world, and it matters even more because it can work in impoverished low-humidity environments.

How it works: During the day, sunlight hits porous materials in the device, creating just enough energy to convert water molecules into vapor. The prototype isn't yet ready to be scaled for broad use, but the teams that developed it at MIT and the University of California-Berkeley believe that it shouldn't take long to test it in arid countries around the world.

Sound smart: The device is built on synthetic, porous materials (called metal-organic frameworks) made of molecules held together with metal atoms.