You are not a bastion of self-control. Everyone has a set amount of the stuff, and when life saps it, people can break. Now fMRIs from a University of Iowa study show exactly what it looks like when that happens.
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.