Slime is a unique play material composed of a cross-linked polymer. It is classified as a liquid and is typically made by combining polyvinyl alcohol solutions with borate ions in a large mixing container. It often has an unpleasant odor, a green color, and is cold and slimy to the touch.Slime is a fun, easy and safe way for kids to learn about chemical and physical changes. Glue has an ingredient called polyvinyl acetate. The borax powder acts as a bonding agent, bonding the molecules together creating one large flexible polymer, which we know to be as slime!