Dissecting Diapers

Experiment # 1

State the Problem

How do disposable diapers work?

Gathering information on the problemBefore 1982, diapers relied on the absorbency of cotton, paper and sponges to hold the, um, liquid in place. Unfortunately, those materials can only hold about 20 times their weight in water. The average diaper doesn’t really weight that much, so 20 times not very much equals leaks.Today we have a much better situation. The use of superabsorbent polymer materials such as sodium polyacrylate has dramatically increased the “storage capacity” of your typical diaper. Sodium polyacrylate was originally developed as an agricultural product. Spread over crop fields it helps even out the drench-drought cycle by releasing moisture as needed. It is a super-absorbing polymer that can hold up to 800 times it’s weight in water. Again, compare that with paper, cotton or sponges which hold about 20 times their weight in water.

The secret water-absorbing powder in a disposable diaper is a super absorbent polymer called sodium polyacrylate. A polymer is simply a long chain of repeating molecules. If the prefix "poly" means many, then a polymer is a large molecule made up of many smaller units, called monomers, which are joined together (think of a chain). Some polymers are made up of millions of monomers. Super absorbent polymers expand tremendously when they come in contact with water because water molecules are drawn into and held by the molecules of the polymer. - See more at: http://www.stevespanglerscience.com/lab/experiments/vanishing-water#sthash.fh4mzD6s.dpuf

Materials

DiaperZip lock bagScissorsWaterScale

Safety Precautions

Scissors have sharp edges.

Forming Hypothesis

Hypothesize how the diaper works based on the researched information (how might the polymers work).

Performing the Experiment1. Place a new (definitely unused) diaper on the

table. Use scissors to carefully cut along the center of the inside lining and then remove the cotton-like material placing it into the zip-lock bag. Seal the bag shaking the loose powder away from the cotton in a zip-lock bag.

2. Remove all cotton like substance leaving the white powdery/granular substance. Place the bag on the scale for weight measurement. Record this weight.

3. Pour 20 mL of water into the zip-lock bag.record what happens

Repeat three more times.

Recording and analyzing Data

Amount of water

Weight of substance

Observations

0mL

20mL

40mL

60mL

80mL

Stating a conclusion

Having concluded the experiment and research write a summary of how the diaper works based on observations, measurements, and prior research.