This research is a longitudinal single group, three-time repeated measured experimental design. The population consists of 703 students studying Mattayomsuksa 1, 2, and 3 at Chulalongkorn University Demonstration Secondary School in the second semester of Academic
Year 2014. To derive a homogenous group of students, sample consists of 217 Mattayomsuksa 2
purposively selected from the population
.