Abstract: The Problem-Based Learning Strategy (PBLS) is one of the most powerful instructional strategies on learning and achievement, but its impact can be determined arising from the behaviour of the learners who graduate after exposure to it. Its influence has been frequently mentioned in earlier research, surprisingly most educators have systematically and consistently not adapted to it, resulting to lower Learning outcomes from the learners. This study provides the use of PBLS for learner’s attainment of critical thinking skills in public secondary schools in Kenya. The objectives of the study were to determine the extent to which instructors’ use PBLS as a teaching strategy to promote problem solving abilities of girls in Physics and evaluate the gain in problem solving abilities of girls in “Fluid Flow” when using problem-based learning strategy. The study adopted constructivist theories of learning. Quasi-Experimental design was used with 4 girls’ schools targeted in Bungoma County. The study sampled Form two students because the topic of fluid flow is taught at form two. Simple random sampling was used to assign schools to experimental and control groups. The study used motivation questionnaire, physics Achievement Test (PAT) and Observation schedule. Two groups of each n=40 either control or experimental were exposed to pretest and post-test. The reliability coefficient was calculated using KR-Fomulla-20 at 0.75. With the aid of SPSS 26.0, data was analysed using descriptive and inferential statistics and presented in form of tables. Although there was inadequate use of PBLS before the experiment, results show that all the variables were significant.Thus, the use of PBLS as a teaching strategy promotes learners’ CTS at the study area. Similarly, the study found significant difference in the level of girls’ problem-solving abilities towards Fluid Flow, a topic in physics between students who were exposed to PBLS and those taught using conventional methods. There is need for upskilling or retraining of teachers for the adoption and use of PBLS in schools. We recommend the method should be strongly advocated by policy makers, the Government, Principals and teachers while teaching science subjects. The study is important in bringing public sector reforms in the education sector especially with Competency Based Curriculum.

Abstract: The government of Kenya has invested enormous resources such infrastructure development, learning materials and professional development of teachers. Despite the efforts put in place to support access and quality education, enrolment and performance in physics in most Sub-County girls’ secondary schools in Bungoma County at Form 3 remain relatively low and poor. The study aimed at investigating whether learners taught through Problem Based Learning Strategy demonstrate an obligation to conveying positive motivation towards Physics enrolment. The objective of the study was to establish the effect of problem-based learning strategy on girls’ motivation towards “Fluid Flow” as compared to conventional teaching methods. The study adopted constructivist theories of learning. Quasi-Experimental design was used with 4 girls’ schools targeted in Bungoma County. The study sampled Form two students because the topic of fluid flow is taught at form two. Simple random sampling was used to assign schools to experimental and control groups. The study used motivation questionnaire, physics Achievement Test (PAT) and Observation schedule. Two groups of each n=40 were either control or experimental were exposed to pretest and post-test. The reliability coefficient was calculated using KR- Fomulla-20 at 0.75. With the aid of SPSS 26.0, data was analysed using descriptive and inferential statistics and presented in form of tables. Results show statistically significant difference in the ability of Girls to derive the to perform better in the topic of Bernoulli’s effects using PBLS and its effect on girls’ motivation was relatively higher than use of conventional methods (ANOVA (F(4,155) = (Q2 = 459.886; Q16 = 462.375; Q24 = 831.272; Q26 =614.907 and Q28 = 406.743), p =.000). The study recommends the method should be strongly advocated by policy makers, the Government, Principals and teachers while teaching science subjects for effective skill development among the learners. The study is significant in bringing total reforms to CBC that call for the use of learner-centered instructional strategies to develop key competencies.