Dean Campbell tries to use at least one demo for every class to illustrate concepts described in his chemistry courses. In this post, he includes short descriptions of the demonstrations and props he has used while teaching his collegiate General Chemistry II courses.
This timely post is a perfect fit for the theme of Chemists Celebrate Earth Week 2023! Algae is a rich topic with many possible connections to the chemistry classroom. Algae needs to take in light, carbon dioxide, and various simple nutrients and, though it can sometimes get out of control, can produce oxygen, diatomaceous earth, and other products. It can even fluoresce pink!
Diffusion of HCl(g) from concentrated solutions of HCl can be used to illustrate some chemistry related to the train accident in Ohio.
Part 2 includes further anthocyanin experiments to make a connection between the food we eat and the chemical principles that are employed to ensure that canned foodstuffs can be preserved properly.
The theme to the 2022 National Chemistry Week, observed October 16-22, is “Fabulous Fibers: The Chemistry of Fabrics”. A visit to Natural Fiber Welding, Inc. in Peoria, IL, revealed how that company is using ionic liquids to solvent weld cellulose fibers together to produce more durable yarn which can then be made into more durable fabric. The production method and “greenness” of the product is discussed, from the cellulose itself to the recycling of the solution used in the welding process. Macroscopic demonstrations of the fiber solvent welding process are also described.
Learn a bit about the chemical reactions that occur during a lightning strike, and how you can demonstrate these reactions in your classroom.
Flash rocks, typically pieces of quartz that produce light when struck together, are an example of the complex phenomenon of triboluminescence. The green chemistry aspects for the flash rock demonstration are considered, and LEGO models illustrating quartz crystals, piezoelectric materials, and nonpiezoelectric materials are presented.
The reaction of hydrogen and oxygen gases to form water is well known to be an exothermic reaction. That reaction can occur by first absorbing the hydrogen into palladium metal, and then placing the resulting palladium hydride into contact with oxygen in the air. Infrared and visible light videos were recorded for this process involving palladium foil, and the Green Chemistry and safety aspects of these activities are considered.
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.
The classic classroom or lab activity using coin flips to illustrate the first order kinetics of radioactive decay is connected to the tragedy of radiation exposure of workers at facilities using radium-containing luminescent paint. Some of the chemistry related to the contamination of these “radium girls” is explored, with connections being made to the Principles of Green Chemistry and the United Nations Sustainable Development Goals.
