When I was young, I was afraid of the dark. Now I am afraid of getting the electric bill. This fourth lesson in a series of eight focuses on coal mining, conservation, and energy efficiency. Scholars start by taking data from a table and creating a graph, drawing a best fit line or curve, and predicting future data. Next, they analyze a cross-section diagram to determine the best place to drill for coal. The last part of the lesson discusses the environmental consequences of coal, including many connections to math.