In his hilarious book Cat's Cradle, Kurt Vonnegut describes a crystal substance, ice-nine, that turns any water it touches into more ice-nine. The inventor spends a day playing with it in his kitchen (before it destroys the world), freezing pots of water with crystals. When I read that passage, I knew exactly what he was talking about, because I've done it myself.
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.