Crustal Evolution Education Project (CEEP) modules were designed to: (1) provide students with the methods and results of continuing investigations into the composition, history, and processes of the earth's crust and the application of this knowledge to man's activities and (2) to be used by teachers with little or no previous background in the modern theories of sea-floor spreading, continental drift, and plate tectonics. Each module consists of two booklets: a teacher's guide and student investigation. The teacher's guide contains all of the information present in the student investigation booklet as well as: (1) a general introduction; (2) prerequisite student background; (3) objectives; (4) list of required materials; (5) background information; (6) suggested approach; (7) procedure, recommending two 45-minute class periods; (8) summary questions (with answers); (9) extension activities; and (10) list of references. Designed for independent work, this activity serves as an introduction to heat flow (movement from a point of higher to lower concentration), focusing on pattern of flow distribution in rocks of northeast Pacific Ocean and the relationship between heat flow and age of the ocean crust. Skills fostered include interpreting data from a map, plotting a graph, and making interpretations based on the graph. (JN)