Development of Students' Spatial Thinking in a Unit on Geometric Motions and Area

In this study we investigated the application and development of spatial thinking in an instructional unit on area and motions, part of a large-scale curriculum development project funded by the National Science Foundation. We also investigated the role of noncomputer and computer interactions in that development. We collected data from paper-and-pencil assessments and case studies as we pilot tested the unit with 2 third graders and field tested it in 3 third-grade classrooms. Results revealed strong positive effects on spatial abilities and the establishment of spatial-numeric connections; they also provided information about students' strategies for solving the unit's spatial and spatial-numeric problems. A distinguishing feature of these strategies was the degree to which students applied a unitizing operation to construct spatial and numerical units and "units of units.".