The anatomy of a Disposable Diaper.  The outer cover of a disposable diaper is made of special plastic that has been formulated to feel like cloth.  But it's still plastic, and it is waterproof.  Which also means it's air-proof, and that no air circulation is allowed inside the diaper.  The elastic around the legs is tight to prevent any air that might get in through the child's natural movements.

The absorbent middle layer is the essence of the "magic" disposable.  It has a cotton/polyester mesh that covers a powder that will turn into gel when it gets wet. The gel is supposed to stay inside the diaper but it's common for parents to find gel beads on their baby's skin during a diaper change.   The gel will allow for multiple pees before needing a change.  They child will probably not feel wet until the diaper gets very full.  At that point the diaper will have been on the child for several hours, soaked in concentrated pee-gel, and will start to feel mushy.  No air has gotten through all this time and the bacteria is multiplying.  If the child does a bowel movement the gel sucks the moisture out of that too, leading the bm to stick to the baby's skin and have to be practically scraped off during the change.

And parents wonder why their child has diaper rash that won't go away.  To combat the diaper rash they use all kinds of medicated creams.   So the child has against their skin plastic, absorbent gel, sometimes fragrance, and medicine for diaper rash.

I have heard several mothers who use cloth diapers, who have used disposables for trips sometimes, say that the disposables have a much stronger odor than cloth, probably because of the gel that concentrates the urine.  They also leak a lot more often than cloth diapers. 

And don't forget.  Each disposable diaper costs an average of 15-25 cents and has only one use.  The chemical processes that go into making a disposable diaper are harmful to the environment and produce a lot of byproducts.   The biggest byproduct is the diaper itself, which will sit in the landfill and . . . well, just sit and sit until hundreds of years from now it will finally decompose.

Look below:  I poured a little more water on the fluff and it kept growing! 

After pouring just a little water on the fluff it puffed up and the gel beads expanded.

Here's a close-up of the gel slush.  It was very slimy to the touch, and the gel beads stuck to my fingers.  Imagine if these beads were saturated with urine instead of water, and that some poor child was sitting in this for hours on end, bacteria growing all the while.  YUCK!  Not to mention it weighed a ton when I picked it up -- and only about half the fluff was wet.  It was not fully loaded yet.  Can you say saggy, soggy diaper?

Just for fun I compared the slush to a 100% cotton cloth diaper.

The Anatomy of a Cloth Diaper
There are many cloth diapering products available, made of flannel, hemp, and so on.  I'm going to talk about the most common cloth diapering system using Chinese cotton prefolds, a Velcro cover, and a liner.

The Velcro cover can be made of various materials from fleece to cotton to vinyl. The most common cover is waterproofed nylon or cotton.   The waterproofing is done by adding a thin layer of waterproofed material such as vinyl or rubber to the inside of the fabric.  The next layer of a cover is a cotton mesh that allows for airflow to take place between the cover and the diaper.  The leg gussets are elastic but not so tight that airflow is completely restricted.  The covers are opened and closed with Velcro tabs.  Each cover can be used several times before it gets soiled, at which point it can be washed and reused.