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.
Learn the chemistry behind the reaction between calcium carbide and water...melon...?!
A trip to see the 2024 solar eclipse provided the opportunity to explore ideas associated with sulfur in petroleum, sunlight intensity measurements, laser interference patterns from eclipse glasses, and large-scale light emission from excited hydrogen.
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!
Laser cutters can be used to cut and engrave a variety of thin materials. Compact discs, composed of layers of polycarbonate plastic and aluminum metal, were explored for their ability to be shaped with a laser cutter. The laser can successfully cut and engrave the compact discs into the shape of snowflake. However, each disc must first be coated with a material like glue in order to protect the plastic from discoloration and the byproducts from cutting the plastic that can accumulate on the disc surface.
Diffusion of HCl(g) from concentrated solutions of HCl can be used to illustrate some chemistry related to the train accident in Ohio.
In a classic demonstration of energy conservation, smashing two large steel ball bearings generates sufficient heat to burn a hole through a piece of paper. Josh Kenney found this demonstration underwhelming because the paper doesn't look burned. So, he upgraded the experiment by covering the paper in Elmer's Color Changing Glue. Now, a spectacular color change reveals the increase in heat!
Egg cartons and small objects such as milk jug caps or plastic eggs can be used to illustrate chemical concepts. The egg cartons can be cut into trays to represent atoms or to represent energy levels associated with atomic orbitals. The plastic caps or eggs distributed among the dimples of the trays can be used to represent electrons or pairs of electrons.
Some metals and metal alloys undergo a transition to brittleness at cold temperature. This phenomenon likely contributed to the demise of the Titanic.
Describing the number density of molecules involved in chemistry demonstrations while presenting those demonstrations can help to convey concepts such as the small size of molecules and how the distance between molecules can vary during change of physical state.
