Results of several studies on the relationship between science students' perceptions of their classroom environments and their cognitive and affective achievements indicate strong association between the perceptions and the achievements. While this underscores the need for more effective relations in the classrooms, the issue of the effectiveness of some contemporary instructional strategies for teaching science in different classroom environments has not been addressed. This study, therefore, sought to find out if the constructivist instructional strategy can enhance cognitive and affective achievements of students in non-conducive environments. A total of 100 (57 boys, 43 girls) junior secondary two (grade 8) students participated in this experiment. Two instruments-the Cognitive Achievement Test and the Affective Achievement Test-were used in pre and post-test administration to measure the treatment effect on cognitive and affective achievements, respectively. Findings do not support the stand that the constructivist instructional strategy is more effective than the traditional (expository) teaching strategy for improving cognitive achievement. But with respect to affective achievement, the evidence supports the use of the constructivist strategy for instruction in non-conducive classroom environment. Implications of the study are discussed and recommendations given.

Effectiveness of teaching reflects interplay among a number of teacher-variables prominent among which is the teacher's conceptions of teaching and learning. In educational institutions where teachers are educated, the influence of these conceptions on effectiveness is geometric. This is because teacher educators are teachers of teachers and most teachers teach the way they were taught. Two major conceptions of teaching (traditionalist/transmissive and contemporary/constructivist) have been delineated. The purpose of this study was to determine if a majority of teacher educators in Colleges of Education, Delta State Nigeria have contemporary/constructivist conceptions of teaching, and if teacher variables (qualification, discipline and experience) would influence their conceptions. A customized instrument was administered to 179 teacher educators selected through the use of cluster sampling technique. Results indicated that; a majority of the teacher educators had traditionalist /transmissive conceptions of teaching and learning, qualification and discipline did not influence their conceptions, inexperienced teacher educators had conceptions that were more inclined to contemporary/constructivist conceptions than the experienced teacher educators. Implications of these results for improvement of teacher education programs and for further research have been drawn.

Strands of evidence from research on science teaching support the use of conceptual change pedagogy for teaching science at the primary and secondary school levels (grades 1-12). This model emphasizes the determination of students' alternative conceptions and organizing a conducive learning environment for negotiation between the students and their teachers.Meaningful learning of science takes place within this type of learning environment. Despite this, there is the need to investigate the efficacy of this model for each of the levels of the various characteristics of students. This study, therefore, sought to find out if high achievers in integrated science taught using conceptual change pedagogy will achieve significantly better than their counterparts taught through the expository strategy. A total of 100 (54 boys, 46 girls) junior secondary school (grade 8) high achievers took part in this study. Using a non-equivalent control group design, the experimental group was taught energy concepts using conceptual change pedagogy while a second group was taught using expository method.No statistically significant difference was found between the two groups in cognitive achievement. But a significant difference was found in affective achievement between the two groups. The implications of the findings for integrated science teaching and further research are drawn.

The nature of classroom learning environments created by teachers had been considered very important for learning to take place effectively. This study investigated the effect of creating constructivist and transmissive learning environments on achievements of science students' of different ability levels. 243 students formed the entire study sample, while 146 (70 high and 76 low ability) students took part in the ability groupings. Three research instruments (teaching guides; scholastic ability test and Basic science achievement test), were used to obtain data for which two research hypotheses were tested. The validation and reliability of the instruments were fully established. Results indicate that students in the constructivist environment achieved more. And that the high ability students irrespective of their learning environment achieved more than the low ability students which indicates that learning environments do not have impact on learning ability. However, since the high and low constructivist groups achieved more than the high and low transmissive groups respectively, it is recommended that teachers should create the constructivist environment while paying extra attention to the low ability groups in order to reduce gaps between high and low ability during their basic science classes in Nigeria.

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