Learn a bit about the chemical reactions that occur during a lightning strike, and how you can demonstrate these reactions in your classroom.
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.
Nora Walsh shares the outline of the interactive notebook pages she uses for her thermochemistry unit. All of the documents and foldables are available for download.
The "Two-Faced" thionin reaction involves causing a purple solution to fade to colorless by shining light on the solution. I wondered if it could be demonstrated the color of light that caused this transition.
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.
This blog post includes short descriptions of demonstrations and props that Dean Campbell has used while teaching his collegiate General Chemistry I course.
Did you know that sand can be converted into a mixture of gases that spontaneously ignites in air? The procedures involved are relatively simple to perform, spectacular to observe, and relate to a rich assortment of chemical principles.
Thermal paper such as that used for point of sale receipts typically functions by darkening when exposed to heat. The pigment system used in this paper also darkens when exposed to solvents of intermediate polarity and acids. This enables thermal paper to be used as an inexpensive sort of indicator paper for a variety of demonstrations.
Beautiful, metallic mirrors of copper or silver can easily be formed in test tubes. Simply add the appropriate metal salt to a test tube, and heat! These reactions should be performed in a fume hood.
The blossoms of eastern skunk cabbage produce heat for a couple of weeks in early spring. This heat, which can be detected using an infrared camera, results from oxidation of carbohydrates. The mechanisms behind this process can be used to introduce energy transduction during classroom discussions of thermochemistry.