Design and Development of VH-iSTEM Learning Strategy on Geometric Thinking: An Experts’ Evaluation

In the 21st century, the process of teaching and learning STEM subjects must shift from teacher-centered dominated learning process to students-centered. In this process, students can actively carry out the learning activity and make an experiment to reach their own conclusions. For this reason, this study designed a learning strategy on geometry called VH-iSTEM learning strategy through connections between the iSTEM approach, particularly the engineering design with van Hiele phases to help students improve their geometric thinking skills. Three basic skills in geometric thinking consisting of visualization, analysis, and informal deduction that covered triangles and quadrilaterals are considered in this study. The five-phase instructional model called ADDIE model was adopted in the whole process of design and development of the VH-iSTEM learning strategy. The researchers used quantitative and qualitative approaches to analyze the experts’ feedback on the suitability of the connections between the two phases, the activities provided, and the materials used. Also the VH-iSTEM learning strategy was tested on 30 students to ascertain its effectiveness based on the students’ level of thinking. The result indicated that VH-iSTEM learning strategy was pedagogically functional and effective in improving the geometric thinking skills of students. The researchers used only one group of students to determine the levels of thinking skills. This study is unique based on its ability to connect engineering design with van Hiele phases in learning school geometry.