1. Is there a significant difference between effects of LACC and TDPI on students’ understanding of electrostatics concepts? 2. What is the contribution of students’ science process skills to variation in students’ understanding of electrostatics concepts? The first two questions were analysed by using ANCOVA. 3. Is there a significant difference between effects of LACC and TDPI on students’ attitudes toward physics as a school subject? This question was analysed using t- test analysis.