A burning candle is used as an introduction to air pollution. Students make observations about the candle that illustrate the chemical and physical changes during combustion. The lesson develops the basic ideas that combustion activities are a major source of air pollution and that the products of combustion include particles (soot) and gases such as carbon monoxide and carbon dioxide.
Students answer three essential questions: How does a burning candle illustrate air pollution? What are the reactants and products of burning? What can happen to the air when fuel, leaves, and trees are burned? Concepts include physical and chemical changes, reactants and products of chemical reactions, combustion, incomplete combustion, ambient air, and volatile organic compounds. A background lesson on the composition of the atmosphere and the layers of atmosphere is found on the MEECS Air Quality CD.