We introduce, motivate, and exemplify a proposed theoretical construct guiding the design and facilitation of collaborative geometry activities, conceptually generative perspectival complementarity (CGPC). Participants in CGPC activities learn content by negotiating their respective perceptions of situated features they manipulate to accomplish…

This paper summarizes the pedagogical design, product development and empirical evaluations of the game series, Animal Class, in terms of design study. The design phases, as well as the evaluation phases (N=2718), were carried out between the years of 2005-2007. The pedagogical idea of Animal Class is to place a learner in the role of teacher in a…

This study compared the effects of worked example and problem-solving approaches in individual or group work settings on learning to solve geometry problems. One hundred and one seventh graders from Indonesia were randomly allocated to four experimental groups using a 2 (problem-solving vs. worked examples) x 2 (individual vs. group study) design.…

This study investigated the ways in which the technological tool, The Geometer's Sketchpad, mediated the understandings that high school Honors Geometry students developed about geometric transformations by focusing on their uses of technological affordances and the ways in which they interpreted technological results in terms of figure and…

Discusses solving rotation problems and shows that there is an alternative to using mental rotations or their encoding into verbal terms, namely using geometrical properties. Presents an analysis of the functionality and effectiveness of the different kinds of strategies as a function of the task's characteristics. Describes research to improve…