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 Mountain contours / topography 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 a sand and water erosion activity. Grades taught Gr 3 Gr 4 Teaching Site Gordon Elementary