Messing around with snow polymer is a fun way to pass the time inside on a bad weather day. If you've played with snow polymer before, I encourage you to purchase a pack and experiment with it. Here's one of many different snow polymer products you can purchase.
A container of snow polymer is filled with small, light weight "beads" or "flakes" That in itself is not interesting, but when you add water to the polymer, the fun begins! The beads/flakes begin to expand and do so quickly, reaching sizes that are 10 times or more larger than the original size! Very cool!
This is the same process by which diapers work. Diapers are filled with tiny bead-shaped polymers. When a liquid (urine) is added, the polymers quickly absorb the liquid and grow in size. The diaper grows in size, but the baby/toddler clothes stay dry! When my youngest was still wearing diapers we tested this by tearing a diaper apart and testing how much water the polymers held.
How Does a Diaper Work?
If you don't have polymer snow lying around, but do have a diaper, cut it open and experiment. Do different brand diapers work differently? Does a diaper absorb all liquids the same or are there differences? Give your kids some polymer snow and/or a few diapers and let them experiment!