ISSN 2522-9400 European Modern Studies Journal Vol 4 No 4 available at journal-ems.com 21 European Modern Studies Journal, 2020, 4(4) Effects of Problem-Solving Teaching Strategy on Secondary School Students’ Academic Achievement in Physics Awodun, Adebisi Omotade (PhD) Department of Physics, College of Education, Ikere-Ekiti, Nigeria Abstract. The study investigated the Effects of Problem-Solving teaching Strategy on secondary school students’ academic achievement in Physics in Ekiti State, Nigeria. The study employed two-group pretest-posttest quasi experimental design comprising of one experimental (Problem-Solving) group and a control group. Purposive and stratified random sampling techniques was used to select a total sample of 120 SS II Physics students (this sample was divided into experimental and control groups in ratio 1:1) from three Senior Secondary Schools in Ekiti West Local Government Area, Ekiti State. Three null hypotheses were formulated and tested at 0.05 level of significance. The instrument for this study was Physics Achievement Test (PAT) and the treatment packages used for the study was Problem-Solving Instructional Package (PSIP). The data collected were analysed using t-test and ANCOVA statistical analysis packages. The results of the analyses showed that no significant difference existed between academic achievement of students in experimental group and control group involved in the study at pretest (this indicated initial academic homogeneity of the groups). However, students’ achievement in the experimental group and control group at post-test level was found to be significantly different in favour of the experimental group. This showed that Problem-Solving teaching strategy significantly influenced students’ academic achievement in Physics in Senior Secondary School. Based on the findings of the study, conclusion and recommendations were made. Keywords: problem, problem-solving, academic achievement and instructional package Introduction The teaching-learning process is as old as human being on the earth. It has been carried out by human beings and even by animals, to teach their young ones for successful adjustment to existing conditions in their environments (Owoeye, 2017). Teaching as conventionally understood by the traditional teacher, is just the act of disseminating information to learners in the classroom. An observation of the traditional classroom teaching reveals that either the teacher is delivering information, or one of the students is reading from the text book and other students are silently following him in their own text books. Conventional teaching is simply chalk-talk approach in which students remain passive as learners. Instruction is not properly organized and rote learning is heavily emphasized. Mostly, the results of the students are not satisfactory due to the use of this approach. According to Elif (2018) at every stage of our lives, we encounter various problems, which can sometimes be difficult, and we strive to solve these problems. While trying to solve these problems, either we apply strategies that we used to solve similar problems before or use different approaches. According to Mataka, Coben, Grunert, Mutambuki & Akom (2014) cited in Adegoke (2017) that among the lifelong learning skills that students of all ages need to acquire is Problem-Solving. Individuals solve different types of problems of varying complexities throughout their life cycle. Some of the problems are well-structured while others are ill-structured (Jonassen, 2010). According to Haury (1993) cited in Abubakar and Danjuma (2012), students’ achievement in the school situation can be measured by the degree of success attained in a specific area of learning. The more students score highly in test of achievement, the more the conclusion reached that the teachers are doing well in teaching the subject.