Part of a series of polymer chemistry lessons and experiments under development for Video Science, we offer this particular segment as a "tickler" to encourage students to consider the chemistry and materials science involved in the objects and tools they handle day to day.
The counterintuitive effect of the melting "plastic" is intended to get students thinking about the potential for green engineering of other items. What if all plastics could dissolve and wash away when their intended uses have been served? Are there similar materials in use? Can your students engineer their own green approach to storing, sealing and handling materials at home and school?
Regarding the simple chemistry presented here, the blue "slime" handled here is a polymer, or large molecule built of identical components that are linked together in a chain. A second phase of this activity will entail "linking" the chains to prevent them from sliding over each other (as seen in our footage), "stiffening" the matter into a more viscous form commonly known as "slime". Adding a 4% solution of sodium borate (made by stirring 4 grams of laundry booster into 96 ml of warm water) will allow the borate ions to "lock" the polyvinyl monomers (chemical chain "links") into position in a chemical reaction called a cross linkage or cross link polymerization.
Retain samples of each reactant and ask students to compare the properties of the reactants and product in a simple matrix to show, in a structured way, the qualities of each component in this investigation.
Do you have any recommended science experiments using inexpensive materials? Did you find these ones useful? Let us know what you think.