Clean drinking water is arguably the most basic human necessity, yet in developing countries it’s a rare and precious resource — nearly 900 million people worldwide live without it, according to the World Health Organization. One MIT researcher has a solution: Drink the fog.
Remember when, as a kid, you would pen secret messages with "disappearing ink" by writing on paper with lemon juice? A team of researchers at Northwestern have taken the idea just a little bit further, engineering a nanoparticle ink that fades away at a predetermined time, keeping maps or messages away from spying eyes.
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.