…so you reach for a disposable diaper.  As advertised – baby is kept dry and the “used” diaper is, well, amazingly heavy.

You toss it out, it’s gone.

But wait!  How does the diaper HOLD all that water?

Disposable diapers have been a part of our child-rearing culture ever since Pampers were introduced in 1961 (Johnson & Johnson actually marketed disposables in 1948, but they didn’t catch on like Pampers).  And boy do we Americans  love ‘em!

Over 3.6 million tons of disposable diapers protect little American baby bottoms every year.

But back to our question:  what sort of magic keeps the water in and helps keep our little prince or princess dry?

It’s not magic, it’s just neat chemistry.  So if you’re REALLY the hands-on type, this simple little experiment is easy and fun to do. (GUITV suggests this experiment for scientists ages 6-12)

• Clear a little counter or smooth table-top space and lay out a single sheet of newspaper (not multiple sheets, just one sheet without tears).  Have a small empty disposable paper or plastic drinking cup nearby.
• Take a new, unused disposable like Pampers or Huggies (or even Depends!), while holding it over your paper, slowly tear it open.  You can give a gentle shake as you tear, and you’ll see a white powder falling on your paper.
• The more times you tear, the more white powder will fall out.  The soft stuffing inside is full of it.   Don’t worry, it won’t hurt you – keep tearing to gather more.
• When you have at least a teaspoon full of white powder (the more the merrier), carefully lift up your paper and use it to pour the powder into your small disposable cup.  Don’t use your permanent glassware:   while this powder is NOT toxic or destructive (after all, it’s next to baby’s sensitive skin!) when we’re done, you’ll toss out the cup and contents.
• Now it’s time for the big test:  fill your cup to about 2/3 full with water (either right from the tap or poured from another cup – don’t use cold refrigerated water – it slows everything down).  What happens?

The water you pour in the cup immediately turns into a gelatin-like solid.  You’ll be amazed at how fast this works.  It’s okay to touch it and even press your finger into it.  You shouldn’t eat or drink it, however, and be sure it’s securely tossed away when you’re done.

That’s how the diaper does the job:  the white powder consumes over 800 times its volume in water – which means it can hold a whole lot!  More than a baby can dish out…usually.