Superabsorption

Procedure

• Open the diaper with the help of scissors and carefully extract the powder substance it contains.
• Put a bit of this powder in a crystallizer, add distilled water, and observe what happens.
• Finally, add sodium chloride (or table salt), shake the crystallizer, and observe again what happens.

Theoretical explanation

The powder extracted from single-use diapers is a substance called sodium polyacrylate. This polymer is highly absorbent and turns into gel once moistened. When water is added, it absorbs it, and its volume increases compared to the initial volume. When sodium chloride is added, the large amount of sodium displaces the water from the polymer.