Baby Diaper Secret If you've changed a diaper, you've uncovered polymers. email to friend
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1. Place a new (unused is your first choice) diaper on the piece of newspaper. Carefully cut through the inside lining and remove all the cotton-like material. Put all the stuffing material into a clean, zipper- lock bag.
2. Scoop up any of the polymer that may have spilled onto the paper and pour it into the bag with the stuffing. Blow a little air into the bag to make it puff up like a pillow, then seal the bag.
3. Shake the bag for a few minutes to remove the powdery polymer from the stuffing. Notice how much (or how little) powder falls to the bottom of the bag.
4. Carefully remove the stuffing from the bag and check out the dry polymer you just extracted from the diaper. Amazing stuff!
5. Grab a new diaper and slowly pour about one-fourth cup warm tap water into the center. Hold the diaper over a large pan or sink and continue to add water, a little at a time, until it will hold no more. Keep track of how much water the diaper can absorb before it reaches its limit.

How does it work?

The secret, water-absorbing chemical in a diaper is a superabsorbent polymer called sodium polyacrylate. A polymer is simply a long chain of repeating molecules (monomers). If the prefix poly means many, then a polymer is a large molecule made up of many smaller units, called molecules, that are joined together. Some polymers are made up of millions of monomers. Superabsorbent polymers expand tremendously when they come in contact with water because water is drawn into and held by the molecules of the polymer. They act like giant sponges. Some can soak up as much as 800 times their weight in water! The cotton-like fibers you removed help to spread out both the polymer and the, uh, "water" so that baby doesn't have to sit on a "gooshy" lump of water-filled gel. It's easy to see that even a little bit of powder will hold a huge quantity of water, but it does have its limits. At some point, baby will certainly let you know when the gel is full and it's time for new undies!

ADD SALT... Gather the pieces of gel into a cup and smoosh it down with your fingers. Add a teaspoon of salt, stir it with a spoon, and watch what happens. Salt messes up the gel's water-holding abilities! When you're finished, pour the salt water goo down the drain.

Additional Info

Look for Steve Spangler using the baby diaper experiment as the 2008 National 4-H Youth Science Day Spokesperson.