No other element could make fireworks glow as intensely red. Demand for strontium should fall as users switch from cathode-ray tubes in old-style monitors to flat-panels that use much less of the element. And there’s plenty in the ground and oceans for every Fourth of July to come.
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.