Presented in this unit are three activities designed to illustrate the importance of the Great Lakes in transporting cargo. Students first determine the movement of various materials shipped from selected ports. They then compute from map measurements the distances and relative costs of transporting different cargoes via water, rail and truck. Finally, students compare the energy efficiency and environmental implications of these three modes of transport. Included are a list of objectives, an answer key, teaching recommendations, and evaluation items. A student workbook is also provided. (Author/WB)