gas laws

Surprising Shrinking Styrofoam Stick: Using the Gas Laws to Get a Square Peg into a Round Hole

Polystyrene foam sticks with a square or rectangular profile will not fit into a round target hole (e.g., the opening of a soda bottle) at room temperature. However, they do contract sufficiently in contact with liquid nitrogen to fit into the hole and produce a simple demonstration of Charles’s Law. Many other polymer foams do not shrink under these conditions, but still provide opportunities to discuss and explore their structure and chemistry.

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.