Soak in water and these spheres grow 300 times their size!
These curious growing spheres are made from a chemical known as super absorbent polymer (or SAP). SAPs are amazing materials. They are long chains of molecules that join together in a net-like pattern. Water is pulled in through the holes of the net, then the molecule chains soak up tremendous amounts of water. When the molecules absorb water, they swell and soften and transform into a hydrogel.
After a while out of water, evaporation will dry out and shrink the spheres again.
WARNING: This set contains chemicals that may be harmful if misused. Not to be used by children except under adult supervision. CHOKING HAZARD: Small parts not for children under 3 years.