Abstract. This study aimed to determine the effectiveness of using localized litmus paper and computer interactive simulation in teaching the concepts of acids and bases. The respondents of the study are the grade seven students of a private school in Dumaguete City, during the academic year 2023-2024. The researcher utilized the descriptive, correlational, comparative, and Cluster-Randomized Controlled Trial (CRT) methods of research. This study also made use of researcher-made questionnaires that measured the performance of the students in using the two methods of instruction, respectively. The statistical tools used in this study include standard deviation, mean, t-tests for dependent and independent data, and Spearman’s rho. The findings revealed that there is a significant improvement in the student’s performance after using localized litmus paper (p=0.001 < α=0.05) and computer interactive simulator (p=0.000 < α=0.05). Overall, both methods of instruction proved to be vital and effective (p= 0.597 > 0.05) in the student’s learning of the concepts of acids and bases. The results suggest that both approaches can be valuable tools for educators, enabling them to effectively cater to students’ different learning styles or maximize teaching effectiveness through varied instructional strategies. While using both methods of instruction resulted in comparable posttest success, the usage must be coupled with classroom dynamics, a helpful learning environment, improved study habits of students, and teachers’ positive behavior to achieve higher student performance. Additionally, the findings indicate that both methods are useful teaching tools that the Department of Education and various private basic education institutions can use in teaching acid-base lessons.

Keywords: Localized apparatus; Computer interactive simulator; Litmus paper; Acids and base; Methods of instruction