A new product has become popular among kids called “Squishy Baff”. The product is designed for use in a bath, and can become a fun and gooey science lesson for kids (and adults)!
Osmosis is a process in which water molecules diffuse through the membrane of a macromolecule such as a polymer. In the product “Squishy Baff”, water molecules go through osmosis and diffuse into the polymer Sodium Polyacrylate, which is found in the product. The water diffuses into the polymer, expanding its size. A physical change occurs when water is absorbed, because the polymer can downsize again by evaporation.
Salt is recommended to dissolve the Baff, as directed. The salt appears to “melt” the substance, but a physical change is only being reversed. When salt is added, the bath water becomes a hypotonic solution and draws out the water from the polymer. Polymer chains are broken during this process, preventing water from being absorbed.
Have fun experimenting with different variables! Add food coloring to the water. Does this change the color of the Baff? What effect does temperature have on the Baff’s formation?