The study identified the concept-Electrolysis in Ordinary Level West African School Certificate (WASC) chemistry syllabus as a topic that was not usually well taught by Chemistry Teachers due to either lack of competence or inappropriate pedagogical skills by the Chemistry Teachers. Hence the study examines the relative effectiveness of Computer Simulation Instructional Package (CSI), Four Mode Application Technique (4MAT) and Lecture Method (LM) in improving students’ performance in chemistry. The study adopted a pretest post-test experimental design with lecture method as the control group. The sample consisted of 180 participants selected from three Senior Secondary School II (SSS II) Chemistry Students in Akure North Local Government Area of Ondo State. The sample was classified into two experimental groups (CSI 60), (4MAT 60) and a control group (LM 60). A 15 item instrument tagged Electrolysis Chemistry Achievement Test (ECAT) was developed by the researcher and ascertained for reliability (r 0.78, p<0.05). The study was guided by two hypotheses. Data collected were analysed using ANOVA. The results showed that there was a significant difference in the effectiveness of CSI and 4MAT on students’ performance in chemistry f_(2,177) 7.121. Furthermore, CSI was found to be more effective (X 11.88) than 4MAT (X 11.03) . The study concluded that CSI is an effective method in teaching electrolysis in secondary schools in Nigeria.

4MAT, computer simulation, relative effectiveness, performance, electrolysis