Monday, June 22, 2009

Quick Science--Diapers

Quick if you happen to have a diaper-wearer in the house. Today was one of those mornings where Bamm Bamm was quite active. When the kids asked 'What's that?' of the whitish, powdery substance near where he was sitting, I knew the answer immediately. Bamm Bamm had 'popped' his diaper. Anyone who has had a baby may have had the same experience. The diaper separates at the edge and allows the inner workings to escape. This is, of course, completely fascinating. The escaped inner-workings are what make disposable diapers so effective, sanitary, and healthy for baby's skin.

This material property is widespread. It is also this technology (perhaps even the exact same material) that hospitals use for cleaning up body fluids. Instant snow is also water-absorbing polymers. The gel is also in potting soil to help conserve water and keep plants healthy.

Here is the material: One diaper and about a 1/4 cup of water. Because Bamm Bamm is enormous, this happens to be a size 6 diaper. I liked using a clear glass so you could see from the side.



First thing is to tear open the diaper. The diaper is made in layers. From the outside there is a thin covering over the waterproof layer. After that is a layer of batting, a blue absorbent layer (in Pampers), and then a layer that goes next to baby's skin. Our interest is the layer of fluffy batting.

I still haven't quite figured out the macro mode of the camera, so the next picture is not as focused as it should be. In the batting, there are little bits of a white powder--they're even a little sparkly. They are mixed in with the batting. This is the absorbent polymer that we are going to use for experiments.


There are other ways to get the polymer out, but I just held the torn open diaper over the cup and gave it a shake and a couple of taps. That may also allow some batting to fall in, but I wasn't concerned about that.


You can see the powder in the bottom of the water (and on the countertops).

A few minutes later, there is no separate layer of powder. All of the water has been absorbed.

It's easy to see the gel here. At this point, there is no water left in the cup. It has all been absorbed by the polymer.
Here is Flurpee showing the individual particles. They've expanded immensely from their powdery appearance dry.


It took me MUCH longer to write this post than to show my kids this fun activity. See Steve Spangler for turning this into a more robust experiment.

5 comments:

Rational Jenn said...

Funny that you wrote about this today, because I re-discovered an even quicker, more sure-fire way to get the polymer out of the diaper.

Put it in the washing machine by accident.

:o)

Which reminds me, I've got to go finish cleaning the washer out!

Cool experiment though!

Amy said...

That's awesome!

Principled Parent said...

Very cool. I learned something new today!

Kim said...

I'm glad I could give you guys an idea of something to do with diapers besides change them frequently!

christinemm said...

Fun post.

With macro it is super simple but if you get too close it is blurry. So when macro setting is on you have to sometimes back the camera up a little bit. Usually you can use the zoom to cut in closer to compensate.

There is math behind the camera lens focusing. I'm trying to learn the hard core stuff for SLR cameras but my mind is not getting it yet.