This may come as a shock to hear, but having some basic understanding of biology is important. Thank doctors and nurses, at least someone knows what's going on.
diapers
Via engineerguy
"Bill reveals the stunning engineering underlying the design of a diaper. He describes the five layers of a diaper, including the superabsorbent polymer in the diaper's core. He illustrates the action of this polymer with a stunning demonstration using a single bead of polymer: it soaks up enough water to grow from a diameter of 4 mm to nearly a half inch."
