Click a thumbnail picture below to view a larger version.

View Movie

Narrative
Water is added to a few grams of superabsorbent sodium acrylate polymer. The polymer absorbs the water, forming a gel. The addition of an electrolyte such as sodium chloride collapses the gel. The positively charged metal ions are attracted to the negative charges on the polymer, shielding them from the surrounding water. This changes the interaction between the polymer and water, and the mixture becomes fluid again.