My kids were given this as a gift a long while ago and I finally got it out. There are three packets of "crystals" and we put them in separate glass cups. The review on Amazon is based on the fact that the person who bought them thought that they were actual crystals, not water absorbing polymers.
This turned out to be our first science experiment of the year. The kids had fun watching them grow and observing that some of them were connecting. Then they wanted to find out what would happen if different colors were placed together so we added a 4th cup.
Because this was so much fun I started researching more about polymers which lead me to The Magic School Bus Slime and Polymer Lab.
Please share if you have any experience with these cool science kits? Or have you done any polymer experiments? Please share in the comment section. : )