Finding Flash Rocks

Flash rocks were discussed in a previous post as stones made of quartz that produce light by triboluminescence when struck together. This post provides some description of their origins and tips on how to find them, making connections to some of their properties.

Using My Marbles: Connecting Surface Area and Calorimetry with Temperature Curves and Thermochromic Cups

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. 

Colourful Chemistry of Canning

Educators may be able to use these 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.

KoolAid and similar drinks as convenient laboratory reagents: The weak acid-strong base titration of citric acid or malic acid

The major component of a non-carbonated drink such as KoolAid or a similar beverage is usually a fruit acid, either citric acid or malic acid. The titratable acid (H+) concentration of such drinks has been found to be in the range of 0.02 to 0.04 M. A weak acid-strong base titration of these drinks with 0.1 M NaOH solution is feasible as a student exercise. The use of such drinks as reagents is safe, convenient, and inexpensive. Experiment instructions are included.