@article{UNY23190, journal = {Proceeding of International Conference On Research, Implementation And Education Of Mathematics And Sciences 2015 (ICRIEMS 2015), Yogyakarta State University, 17-19 May 2015}, title = {SHIFTING STUDENTS? AWARENESS OF GEOMETRICAL CONCEPTS THROUGH LESSON STUDY}, author = {Adulyasas Lilla and Abdul Rahman Shafia}, year = {2015}, publisher = {Faculty of Mathematics and Sciences Yogyakarta State University}, abstract = {Students? performance in geometry and hence, their geometric thinking remain a concern for researchers globally. This quasi-experimental research design aims to investigate the effects of Phase-Based Instruction (LS-PBI) using Geometer?s Sketch Pad to reveal Thai students awareness of geometric concepts. Three groups of mixed ability Grade 7 students (aged 12 ? 13) were chosen as participants in one of the schools in Yala Province, Thailand. These groups were taught the topic of Properties of 2D and 3D geometric shapes in a cycle of three instructions by three different teachers engaging in Lesson Study method. A twelve-item multiple choices test was administered to students in each group before and after each lesson study session to assess their understanding of geometrical concepts. Findings of the pre-tests and post-tests revealed that LS-PBI using GSP was effective in revealing students? shifts in awareness of geometrical concepts. Keywords: Geometer?s Sketchpad, Geometric Thinking, Geometry, Lesson Study}, url = {http://eprints.uny.ac.id/23190/} }