Abstract:
Physics is recognized today as a fundamental part of both science and society. Knowledge of physics provides solutions to many of the problems that occur in today’s world. Deficiency in linking physics knowledge to real-life context of problem-solving by learners is however a major problem in the Kenyan education as evidenced by results in KCSE Physics national examinations. Progressive research recognizes the importance of teaching thinking skills through appropriate methodology as key to developing learners’ problem solving ability. The study investigated the effects of PBL instruction on learners’ acquisition of core critical thinking skills in physics in Nakuru East and Nakuru west Sub-county secondary schools using Solomon Four non-equivalent Control Group design. A sample of 154 students from four schools obtained through stratified random sampling was used in the study. The students were selected from the population of 1,108 form three physics students in the Sub-counties. Independent variables for the study were PBL mode of instruction and the conventional teaching, while dependent variable were learners’ core critical thinking skills in physics. The instrument for data collection was the Core Critical Thinking Skills Physics Achievement Test (CCTSPAT) prepared by the researcher, reviewed by three specialists in physics education from Egerton University and four qualified and experienced physics teachers. Reliability of the CCTSPAT instrument was determined through internal consistency reliability estimation using Cronbach’s Coefficient alpha. Two independent samples of thirty form three physics students from two schools of similar characteristics as sample schools were used in a pilot test in which an acceptable Cronbach’s α value of 0.74 was obtained. Data collected was analyzed using both descriptive and inferential statistics. Differences between means of the four groups were analyzed using ANOVA while ANCOVA was used to reduce experimental errors. All hypotheses were tested at α equal to 0.05 level of significance. The study established that the achievement of analyzing skills by students taught by PBL was higher than that of students taught using conventional methods but not significantly different(ANCOVA results for F was equal to 1.205 at df(3,134) and p<0.05). The study however found that the achievement of applying skills by students taught by PBL was significantly higher than that of students taught using conventional methods (ANCOVA results for F was equal to 9.287at df(3,135) and p<0.05). The study established that PBL may be used as a suitable intervention for developing applying skills in learners in physics in the topic of ‘heating effect of electric current’ but was inconclusive about developing learners analyzing skills in a similar way. Use of PBL is likely to improve the physics curriculum in Kenya by enhancing its capacity to develop applying skills and perhaps analyzing skills in learners. Students taught using PBL are likely to acquire more analyzing and applying skills in Physics, and better subsequent preparation for problem-solving in real life than those taught using conventional instruction. The study revealed some fundamental skills to be acquired by teachers, critical considerations for effective implementation of PBL instruction in the classroom and guidelines for curriculum developers on PBL integration into the Kenyan physics curriculum. The study recommends that classroom practices in Kenyan schools should be reviewed so as to incorporate instructional approaches such as PBL that promote inquiry and increased learner engagement.