Geometry is the core module in mathematics counted as one of the problematic topics for the secondary school students. This research focuses on the design of teaching and learning in the 21st century to support the students’ needs for learning geometry. The purposes of this study were four-pronged, that is, to develop the tablet application for enhancing geometric thinking of secondary students in learning geometry with van Hiele’s phase based learning, to determine the efficiency of the tablet application, to study the secondary school students’ improvement in terms of level of geometric thinking and achievement score after learning geometry on the tablet application with van Hiele’s phase based learning, and to examine attitude towards learning. This study was carried out with 189 secondary school students in the three Thailand Southern schools where were selected based on a twostep purposive sampling. The students took geometric thinking tests before, during, and after the intervention and responded to a questionnaire after learning. An E1/E2 formula with a standard criterion of 85/85 was used to determine the efficiency of the tablet application. Descriptive statistics was used to determine the students’ geometric thinking and attitude towards learning while pair sample t-test was used to compare the students’ geometric thinking before and after learning as well as to compare the students’ posttest and delayed posttest scores for examining learning retention. The findings revealed that 1) level of the efficiency of the application was 85.98/87.11 which fullfilled a standard criterion of 85/85, 2) the students’ level of geometric thinking after learning with the application was greater than learning without the tablet application and that enabled the students to achieve level 3 (i.e., abstraction) 3) the students had learning retention after the completion of study, and 4) the students were very satisfied with learning geometry on the developed application.
Volume 12 | 04-Special Issue