Up to 85 percent of injuries in bomb attacks are caused by flying glass—“knives and daggers,” in the words of blast engineer Tod Rittenhouse. But thanks to commercial pressure for views and a graceful exterior, the Freedom Tower’s skin will be mostly glass. Designers will use safety glass, but have not provided details. There are two ways to pacify glass: tinker with it chemically or keep it from traveling.
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.