Teachers' Discernment of Invariant Properties in a Dynamic Geometry Environment

• In Event: AERA Poster Session 4
  In Poster Session: Mathematics Education Research Poster Session 1

Abstract

In this study we investigated the ways high school teachers discerning invariant properties in a Dynamic Geometry Environment (DGE). We interviewed six teachers about four situations to understand how they attended to invariant properties. We then categorized the types of invariant properties the teachers described. Our findings show that teachers are more likely to consider invariant properties when prompted than when left to describe the DGE alone. We also identified four categories of invariant properties that were important to these teachers for a rich and deep understanding of geometrical objects in a DGE. It seems that environments as DGEs may have structural affordances in accessing geometry dynamically, especially when seeking for invariant properties.

Authors

• Gal Gili Nagar, Yeshiva University High Schools

• Chandra H. Orrill, University of Massachusetts - Dartmouth

• Stephen J. Hegedus, Southern Connecticut State University