Sodium polyacrylate: a super strong desiccant
How to make an artificial snowdrift and immediately "melt" it
Warning! Only under adult supervision
- table salt;
Cut a few diapers and pour their filler into a glass. Fill a plate with water and pour the filler on it – the filler absorbs most of the water and increases dramatically in size, beginning to resemble snow. Fill a glass with this "snow," add three teaspoons of table salt, and stir with a spoon – the snowdrift “melts” into a cloudy liquid.
Sodium polyacrylate’s long molecules contain many carboxyl groups. These carboxyl groups attract a lot of water, which causes the sodium polyacrylate powder to swell and increase significantly in size. This effect is reversible: when table salt is added, osmotic pressure arises, which draws the water molecules out of the structure of sodium polyacrylate – yielding liquid once again!
A similar experiment is included in the “Chemistry of winter” set from the MEL Chemistry subscription.