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.
This Pumpkinator is a fantastic orange-to-blue-to-orange chemical reaction that will make a great addition to your Halloween-themed chemistry demonstrations.
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.
A variety of resources are available for chemistry faculty interested in incorporating lessons and activities around art and archeology. Find out what they are in this follow up post from the inaugural ChemEd X virtual Journal Club held April 2022.
The importance of surface area can be illustrated by adding spherical solids at known sizes and temperature to other substances at different temperatures and then monitoring the rates of temperature changes of the system over time. Larger spheres (with less surface area per sample) exchanged heat with water more slowly than smaller spheres, and less thermally conductive glass spheres exchanged heat with water more slowly than iron spheres. Additional, more colorful demonstrations are described in which small glass spheres cool thermochromic plastic cups more quickly than larger glass spheres.
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.
You can solve Chemical Mystery #20 if you know your chemistry...and your magic!
Why does the "Whoosh Bottle" experiment behave differently at different temperatures?
Continuation of the practical application of chemistry to seemingly something unrelated- global maritime trade. In this classroom activity students predict the buoyancy (and hence stability) of a merchant cargo ship based on interpretation of seawater surface salinity values. Like in the first three posts, the question types are conceptual.