Making slime is a lot of fun but there is a lot more to chemistry and in fact, many of the things we come across in our daily lives enabled by chemistry. Chemists study how matter or “stuff” changes when they are combined or how they react to each other. They then use their knowledge of how different matter behave to invent useful solutions.
Diapers are a great example of chemistry at work. How exactly do they hold so much liquid? Let’s explore!
What you need:
Diapers (size doesn’t matter)
Food Coloring
Water
Disposable Cups
Spoon for mixing
Scissors
Steps:
1. Open up the diaper and lay it out flat on a tray.
2. Mix together one cup of water and a drop of food coloring
2. Mix together one cup of water and a drop of food coloring
3. Slowly pour your colored water mixture on to the padding of the diaper and watch how much of the liquid it absorbs. Keep adding water until the diaper stops absorbing it.
4. Use scissors to poke a hole in the lining of the diaper and peel of the top layer.
5. A gel-like substance should now be exposed and you can touch and feel it.
6. Put another diaper in a big ziplock bag, cut open the lining and shake to get the gel granules out.
7. Use a spoon to scoop as much of the granules as you can into a cup and throw away the rest of the diaper.
8. You can now explore the properties of this substance more closes.
9. Add some water into the cup holding the granules and watch it become gel as it absorbs water.
10. Be sure to wash your hand after touching or playing with the gel.
What makes it work?
Diapers are made with a substance called sodium polyacrylate. When exposed to water, its molecules stretch and straighten making room for even more areas to be attracted to water. It absorbing power is what keeps babies that still wear diapers happy and comfortable :).
What other problems could you use sodium polyacrylate to solve?
Consider other scenarios where there is a need to absorb large amounts of liquid. For example, Florists use sodium polyacrylate to preserve water and help retain the freshness of flowers.
Reference: Diapers, The Inside Story – American Chemical Society
For your safety, you should always use personal protective equipment (PPE) when conduction STEM experiments. PPE can include gloves, goggles, coat and more.