The world has improved a lot. The vision to make people’s lives enjoyable came faithfully through the efforts of scientists in developing technologies that will help people’s work easier. This study determined the effectiveness of Activity-Based Strategy in teaching science to Grade 7 high school students in a national high school in the Philippines. The method used in this study was a quasi-experimental design with control and experimental groups. The experimental group was taught using an activity-based strategy, while the control group used the teacher-centered approach. Pretest and posttest methods were used to measure the level of academic performance of the students in both groups. This study revealed that the pretest performances of the control and experimental group were low, but the posttest of both groups increased. Also, there is a significant difference in the posttest performances of both groups in Earth Science. The study concluded that science teaching for Grade 7 students could be enhanced by using the activity-based strategy, a better alternative to improve students’ performances. Activity-based strategy in Science 7 increases the students’ motivation in terms of mastery of the concepts skills, stimulating positive learning and interest, and love for science.