Plane-Sphere Comparative Geometry: An Experiment in the Third Grade of Primary School

The main aim of our research was to teach basic concepts of spherical geometry to elementary school children, constantly comparing the spherical concepts with those of plane geometry. Twenty-eight third-grade students participated in playful activities dealing with elements of plane geometry and spherical geometry simultaneously. We have found that it becomes completely natural for third graders to compare two different worlds of geometry. This activity is beneficial not only for introducing spherical geometry, but also for a deeper understanding of planar geometry. In addition, spherical geometry contributes to better understanding of geographical concepts and orientation on the earth-globe. The post-test results confirmed our assumption about the advantages of comparative plane-sphere geometry in lower grades. Children who were considered less gifted in the subject showed interest and activity in these classes. Our experience suggests that further research on this topic may be necessary and fruitful with a larger sample of students.