Ions or Molecules? Polymer Gels Can Tell

In this Activity, students first prepare a gel using the superabsorbent polymer sodium polyacrylate (found in certain diapers) and water. The gel is split into piles and samples of different compounds are sprinkled on the piles. Students determine that ionic compounds break down the gel, while covalent compounds have no effect on the gel. This Activity strengthens understanding of the differences between ionic and covalent compounds. It could be coupled with an investigation of the effect of these two classes of compounds on electrical conductivity when added to water. The Activity also ties in well with a discussion of how science is used in the design of consumer products.