Everybody loves summer. And as the sun starts to set, and the fireflies twinkle, and bedtimes are some ancient school-day memory, you crack a glow stick and are amused for hours… and your parents have a way to keep an eye on you.But how do these wonders of creation work? Why do I have to ‘break’ it before it lights up? How come it doesn’t last forever? Chemistry, my child. Chemistry.