Investigating nappies

I have carried out this investigation with primary children through to KS4. Primary children particularly enjoy the context, and like to bring in the nappies from younger brothers and sisters. It could be used at A-level to discuss structures and bonding.

How Science Works
Media and bias: which is the best brand of disposable nappy?
Environmental considerations: which is better, to use detergent and cloth nappies, or to use disposable nappies?
Historical context: Space programme, disposable nappies developed as maximum absorbency pads for Space travel

SC1 investigation: Testing absorbency

1 Cut open the nappy and remove the padding. Put the padding into a plastic food bag. Shake the bag until the white powder like substance has separated out.

2 Put the powder into a large glass beaker and add measured quantities of water. Stir with a glass rod. The powder will swell into a gel and thicken. Keep adding water until it no longer continues to thicken.

You will be surprised at the large quantity of water absorbed.

Try other methods of testing absorbency designed by the students. Lots of opportunity here for discussions on fair testing, accuracy and reliability.

Last updated: 31 January 2008