Why Big Babies Leak, Part 1

Little tykes have it all. They get to be carried around, cuddled, can take stuffies anywhere, and can fit into off-the-rack baby clothes. They even have physics on their side: Babies are physically less apt to leak. They benefit from surface area, curvature, and shear scale. The unfairness of physics is enough to make an adult baby cry.

To start with, babies have the advantage of surface area. Consider a baby cube. Let's say its a girl cube, one baby cube tall. Each of her six square sides will have a surface area equal to her width times her height. 6x1x1=6. Her diaper will cover some of this surface area. The baby cube will have a volume equal to her width times her height times her depth. 1x1x1=1. Some fraction of this volume would be bladder. The rest of her body will be generating waste to go throught the bladder. The baby cube will also be able to be changed in public, but I digress.

In contrast to the baby cube, we have an adult baby cube. (The mathematics would apply equally to a diaper lover cube.) Let's say that the adult baby cube was two baby cubes tall. Each of his six sides would have a surface area equal to his height times his width. 6x2x2=24. That is, it has four times as much surface area as the baby cube. In turn, his volume would be equal to his height cubed. 2x2x2=8. That is, he has eight times are much volume as she does.

Since the adult baby cube has eight times as much volume, he would generate about eight times as much urine. Unfortunately for him, he only has four times as much surface area to wrap a diaper around. Every square inch of diaper has twice as much pee to soak up.

Any urine that isn't instantly absorbed by the diaper runs down towards the leg or waist gathers. Some will be absorbed before it hits the gathers. The rest runs up against the gathers at the legs or waist. Here again, physics favors babies, as part two will show. It just isn't fair.

Take care

~BitterGrey

Email BitterGrey Level: General | Status: Finished | Last Update: 12 June 2009| First Posted: 20 Sept 2006

	Related Topics: A New Yorker article on how disposable diapers are getting "Smaller"