This publication presents the activities pertaining to the third goal of this activity guide series. The activities in this publication focus on understanding conservation processes, efficiencies, socioeconomic costs, and personal decision-making. These materials are appropriate for middle school and junior high school students. These activities, organized by objective under the concepts listed, are interdisciplinary and can be used in many ways. The activities are simply ideas of things that students can do to help them understand the concepts. It remains for the teacher to choose and implement these ideas as desired. Activities range from stating the first and second laws of thermodynamics so the students' parents can understand them to designing a house which runs entirely on solar energy. (MR)