Place these hard crystals in water and they expand about 300 times, producing gel-like spheres. Students love to feel the slippery, spherical gel! The Regular size starts with a diameter of about 2 mm and ends with a diameter of about 14 mm. Ask students to determine the change in volume, using V = πr3. Great for starting seeds and growing plants so that the roots can be seen! Can be tinted using food coloring. The polymer is similar to our super-absorbent, polyacrylamide polymer (GB-5B and GB-3) and can be dried and reused. Small (~1 cm expanded), Regular (~1.4 cm expanded) or Jumbo (~3.3 cm expanded)! (Each package contains 50 grams.)
| Item # | Style | Size | Grams | # of Spheres |
| GB-702 | Small | ~1 cm (0.4") | 50 | ~3000 |
| GB-710 | Regular | ~1.4 cm (0.55") | 50 | ~2500 |
| GB-730 | Jumbo | ~3.3 cm (1.3") | 50 | ~870 |