The Science of Polymers

Right before break, the Kindergarten students learned about the chemistry of polymers.  They took hydrophylic, or water loving, plastic alligators and placed them in water for a week.  At the start of the experiment they were about 11 cm long.  I posed a question to them; "What do you think will happen to the alligators in the water?"  There were many hypotheses, such as "They will melt!", "I think they will change color."  After a week in the water, the students were very surprised to see that the alligators absorbed the water and became huge!  Some were as big as 35 centimeters!  We also grew "water jelly crystals" that even changed color since we added food coloring.