2. Methodology
Model of this experimental research was pretest-posttest design with control group. Both two groups included
twenty four each student mathematics teachers. In order to obtain data, Santa Barbara Solid Test designed by Cohen
and Hagarty to measure ability of identifying cross sections that are 2D slices of 3D objects was used (Figure I).
Alpha coefficient for reliability of the test which contains 30 multiple choice items was found 0.84.In instruction of experimental group, problem based activities was solved with using dynamic tools and a project
study was carried out on SketchUp environment while traditional geometry activities was applied to control group
with using only paper and pencil. Before instructions, researchers introduced basic tools and showed usage of the
software to experimental group. Afterwards, students made practice on the software to gain experience about using
toolbars and building up basic objects. Next lessons students solved problems about solid objects with manipulating
and analyzing 3D simulations of objects on dynamic environment. At these lessons SketchUp gave students some
opportunities as sketching, rotating and cutting solid objects. On the other hand, control group solved same
problems on paper without getting help from computer or any dynamic material.
In project study, at firs
experimental group designed buildings having different and complex geometric shapes on SketchUp; then they
measured their surface area and volume with using measurement tools of the software and drew their surface
developments on paper. At the final lesson, students in experimental group made virtual presentations of their own
products to researchers (Figure II).