Summary Build models of mountains from a contour map, then use sand and water to explore how water erodes mountain sides. Science content Earth/Space: Landforms, Erosion (3) Activities in this lesson Landform models Erosion and Stream flow Procedure Build mountains using a contour map, to understand how their shapes are represented on maps. Discuss how mountain shapes are changed by water flow and erosion. Watch erosion in action with the sand and water erosion activity, at table groups of four, or as a demonstration. Wrap: Erosion by water, as well as ice and wind, slowly over thousands of years, changes the landscape. Maps need to change to reflect that. Grades taught Gr 2 Gr 3 Gr 4