Hydrogels are Swell

Hydrogels are substances that can absorb and retain extremely large amounts of water relative to their own mass (but don’t tell this to your students yet). They are part of a family of compounds called Superabsorbent Polymers (SAPs) that are unique in their ability to absorb tremendous amounts of certain liquids.  In Part 1 of this lesson, students are given a sample of a hydrogel (sodium polyacrylamide) and are asked to make careful observations to record the changes in the hydrogel after placing it in water.   They are then asked to develop an explanation that can be used to explain the changes that have been observed.   After sharing and discussing their ideas, students read/research to learn more about the unique and useful properties of hydrogels. In Part 2 of this lesson, students design their own simple experiment that can help them to learn more about the properties and/or usefulness of hydrogels.    

Key Concepts: matter, materials, mixtures, properties, polymers.