Running down the far-left column of the periodic table, the readily available alkali metals: lithium, sodium, potassium, rubidium and cesium—all generate potentially explosive hydrogen gas when they touch water. The strength with which they react with H2O goes up steadily in the order listed. Lithium just sizzles, whereas cesium explodes powerfully and instantly. You’d expect that to mean that cesium makes the biggest explosion, but it’s not the case.
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.