Looks like fun, and will probably get messy!YouTube
Have a ball with this fun polymer science experiment! Watch in amazement as your polymer balls which starts out smaller than a small marble grows to the size of a racquetball when placed in water-all in less than a day! Comes in an array of vibrant colors that hold true, even when hydrated. They roll, and even though they do not bounce, they will explode when thrown or dropped! Drop the balls in water and imagine the endless possibilities as they grow before your eyes!