Abstract: | The effects of a dynamic instructional environment (based on use of The Geometer's Sketchpad, N. Jackiw, 1991 , in a computer lab) and visualization on eighth-grade students' (N= 241) construction of the concepts of reflection and rotation were investigated. Also investigated were the effects of the environment on students' two- and three-dimensional visualization. After controlling for initial differences, it was concluded that students experiencing the dynamic environment significantly outperformed students experiencing a traditional environment on content measures of the concepts of reflection and rotation, as well as on measures of two-dimensional visualization. The students' environment did not significantly affect their three-dimensional visualization. |