ABSTRACT

 The study was aimed at determining the effects ofthink aloud and selfassessment instructional strategies on students’ achievement in senior secondary school chemistry in Imo State. Four research questions and four null hypotheses were formulated to guide the study. The research adopted quasi experimental design. The population for the study comprised 7,825 chemistry students of 2017-2018 sessions in public secondary schools in Imo State. A two stage samplingprocedure was used to draw 128 chemistry studentsfrom the three intact classes which were used for the study. A 50 item multiple chemistry achievement test (CAT) with optionsA-Eas developedwhich covered the SS2 chemistry curriculum. The content areas are: Rate of chemical reaction, energy change and chemical reaction, chemical equilibrium, energy change (Endothermic and Exothermic reaction), energy change (Hess Law, lattice energy, law ofthermodynamics, enthalpy and entropy change), energy change (energy of reaction, bond energy, enthalpy, entropy andfree energy changefThe reliability ofthe instrument was determined using Kuder-Richardson KR-20 and it yielded estimate of0.86. The data collected were analysed using mean and standard deviationforresearch questions while the null hypotheses were tested using Analysis ofcovariance (ANCOVA) at 0.05 level ofsignificance. The findings ofthe study, among others, showed that there was a significant difference in the mean achievement scores ofchemistry students taught think aloud, selfassessment and conventional method. Students taught using think aloud instructional strategy and selfassessment instructional strategy performed significantly better than students taught using conventional method. It is recommended that chemistry teachers should use think aloud, self assessment instructionalstrategies in teaching and learning ofchemistry