The purpose of this activity is to make students aware that there is no free energy source for the present or the future and that all technologies are potential threats to the environment. The activity consists of a short reading (discussing basic trade-offs, issues, and decisions related to petroleum, coal, and nuclear energy sources) and student exercises. Objectives and instructional strategies are provided for these exercises in which students research and evaluate environmental, societal, and monetary costs of energy sources. The key for students as decision makers is to pick the energy source least likely to be permanently harmful or the one that has the smallest total effect. (JN)