Elementary students demonstrate conflicts when measuring with rulers as well as measuring with discrete units. Their conflicts often lie in their focus on counting tick marks or focusing on the endpoint of objects on rulers or ignoring spaces with discrete units. In this study, we also investigated another area of conflict: students' conceptions…

Spatial abilities--required in both academic and everyday information processing--are recommended as an important target for explicit instruction in the K-12 curriculum. However, most school curricula do not address this spatial issue, probably because spatial ability is a general rather than domain-specific skill and also due to debate regarding…