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The purpose of this study was to find out if there is a relationship between teacher-learner interactions and laboratory learning environment in Chemistry practicals in Namibia. Literatures and questionnaires from 1383 learners and 12 teachers have proven that the interactions between teacher and learners have great impact on the performance, understanding and the environment that prevail in the laboratory. The main data collection methods used was the mixed method research through the use of questionnaires and interviews. The results from the study show that good teacher-learner interactions have contributed to the positive learning environment that prevails in Namibian schools. Although the majority of the learners especially the girls have negative connotations towards Chemistry in terms of content, calculations and assessment generally learners look forward and are excited to do experiments in practical work. The impact of the excitement and willingness of learners to do practical investigations has not proven to improve learners‘ performance in Chemistry practical work in Namibia. The majority of the learners rated their teachers as good in subject knowledge, good leaders, helpful and friendly during practical investigations. The shortage of chemicals, equipments in laboratory activities that should have inspired involvement of learners in handling equipments is one of the factors that contributed negatively to the learning environment and teacher-learners interactions. Teachers mostly resolve to demonstrations due to lack of chemicals and equipment. Some schools show low/poor level of learner-learner interactions because some learners tease, laugh and discourage others during practical investigations. Chemistry laboratories in Namibia are characterised by lack of equipment, chemicals, poorly behave learners while on the other hand there are good behaviours from the teachers‘ side with most learners showing that their teachers always try to make the best out of the prevailing situations in the laboratories. The laboratory environment in Namibia closely resemble laboratory environment in other studies in Asia, Africa and Europe. From empirical evidence it can be therefore concluded that there is a relationship between teacher-learner interactions and laboratory learning environment in Chemistry practicals in Namibia. Although the relationship is not as harmonious or congruent as it ought to be, the government of Namibia can play a greater role in creating positive, productive and enjoyable learning environment by supplying secondary schools‘ laboratories with the needed equipment and chemicals to support the practical work as stated in the Physical Science syllabi. The three questionnaire used were rated by learners and teacher as effective; easy to understand; covering most areas of the Chemistry environment; not time consuming, statistically valid and consistent. The changes made to the questionnaire fit well to the Namibia Chemistry environment and it produced nearly the same reliability and validity when compared to the pilot study questionnaire and other similar questionnaires used in other country. / Curriculum and Instructional Studies / D. Ed. (Didactics of Education)

The purpose of this study was to find out if there is a relationship between teacher-learner interactions and laboratory learning environment in Chemistry practicals in Namibia. Literatures and questionnaires from 1383 learners and 12 teachers have proven that the interactions between teacher and learners have great impact on the performance, understanding and the environment that prevail in the laboratory. The main data collection methods used was the mixed method research through the use of questionnaires and interviews. The results from the study show that good teacher-learner interactions have contributed to the positive learning environment that prevails in Namibian schools. Although the majority of the learners especially the girls have negative connotations towards Chemistry in terms of content, calculations and assessment generally learners look forward and are excited to do experiments in practical work. The impact of the excitement and willingness of learners to do practical investigations has not proven to improve learners‘ performance in Chemistry practical work in Namibia. The majority of the learners rated their teachers as good in subject knowledge, good leaders, helpful and friendly during practical investigations. The shortage of chemicals, equipments in laboratory activities that should have inspired involvement of learners in handling equipments is one of the factors that contributed negatively to the learning environment and teacher-learners interactions. Teachers mostly resolve to demonstrations due to lack of chemicals and equipment. Some schools show low/poor level of learner-learner interactions because some learners tease, laugh and discourage others during practical investigations. Chemistry laboratories in Namibia are characterised by lack of equipment, chemicals, poorly behave learners while on the other hand there are good behaviours from the teachers‘ side with most learners showing that their teachers always try to make the best out of the prevailing situations in the laboratories. The laboratory environment in Namibia closely resemble laboratory environment in other studies in Asia, Africa and Europe. From empirical evidence it can be therefore concluded that there is a relationship between teacher-learner interactions and laboratory learning environment in Chemistry practicals in Namibia. Although the relationship is not as harmonious or congruent as it ought to be, the government of Namibia can play a greater role in creating positive, productive and enjoyable learning environment by supplying secondary schools‘ laboratories with the needed equipment and chemicals to support the practical work as stated in the Physical Science syllabi. The three questionnaire used were rated by learners and teacher as effective; easy to understand; covering most areas of the Chemistry environment; not time consuming, statistically valid and consistent. The changes made to the questionnaire fit well to the Namibia Chemistry environment and it produced nearly the same reliability and validity when compared to the pilot study questionnaire and other similar questionnaires used in other country. / Curriculum and Instructional Studies / D. Ed. (Didactics of Education)

D. Tech. (Department of Chemistry, Faculty of Applied and Computer Sciences), Vaal University of Technology. / In this study, few layer graphene (Gr) and heteroatom graphene (HGr) were synthesized by chemical vapour deposition (CVD) method. Acetylene gas was used as carbon source for the synthesis of graphene, while a mixture of nitrobenzene and dichloromethane (ratio 1:1) were used as both carbon and dopant sources for the synthesis of the heteroatom graphene (HGr). A mixture of argon and nitrogen gases were carefully combined and used as carrier gasses and purge for both the synthesis of graphene and the synthesis of heteroatom graphene. X-ray diffraction (XRD) characterized showed that the as synthesized materials were crystalline materials, Raman spectroscopy indicated that the synthesized materials consist of sp2 hybridized carbon atoms, while scanning electron microscopy (SEM) and atomic force microscopy (AFM) results showed that the synthesized materials possess regions of 2 to 7 nm of thickness. Transmission electron microscopy (TEM) characterization also showed that the synthesized heteroatom graphene possesses about 5 to 7 layers with about 2 nm thickness, and x-ray photoelectron spectroscopy (XPS) result showed the presence of nitrogen, oxygen and chlorine in the lattice of the synthesized heteroatom graphene while the synthesized material still retained about 80% sp2 hybridization. The synthesized materials were used in the fabrication of modified bioelectrodes for electrobiocatalytic biosensing of glucose and hydroquinone. The fabricated bioelectrodes were characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The CV characterization showed a diffusion-controlled electrode processes in al modified electrodes, while the EIS characterization showed the presence of both diffusion controlled and kinetic controlled impedance at the electrode-electrolyte interface. The fabricated GC/PEDOT-PSS/HGr/Lac modified bioelectrode exhibited a kinetic controlled impedance of 3150 Ω, while the fabricated GC/PEDOT-PSS/Gr/Lac modified bioelectrode exhibited a kinetic controlled impedance of 4138 Ω. Chronoamperometric experiments showed that the fabricated bioelectrodes exhibited swift electrobiocatalytic activity towards glucose and hydroquinone sensing respectively for graphene and heteroatom graphene. The graphene modified bioelectrode exhibited a linear response of 0.2 to 9.8 mM glucose concentration and a sensitivity of 87.0 μA/mM/cm2, while the heteroatom modified bioelectrode also exhibited a swift response to step by step addition of hydroquinone with a limit of detection of 2.07 μM and dynamic range of 2.07μM to 2.97 mM, thus indicating the tremendous potential of the materials in a wide range of electrobiocatalytic and bioelectronics applications.