elementary school science

Demonstrating the Glass Transition of Polylactic Acid with a Rattle

Polylactic acid (PLA) exhibits a glass transition from hard and brittle to soft and rubbery when immersed in boiling water. PLA-based structures containing a small metal object can be used as rattles when they are shaken. The sound of the rattles change when they are heated above or cooled below their glass transition, enabling them to be used as demonstrations.

Expanding on Self-Inflating Balloons: Activities Involving Moles, Gas Laws, and Thermochemistry

Balloons that inflate using carbon dioxide produced from the reaction of citric acid and sodium hydrogen carbonate can be used to demonstrate a number of aspects of chemistry. Gas laws were used with the balloons to illustrate limiting reactants, molar mass of gases, and rockets. The endothermic reaction in the balloon was visualized with an infrared camera, and the Green Chemistry aspects of these balloons were considered.