This study compared the effects of a constructivist-visual mind map teaching approach (CMA) and o... more This study compared the effects of a constructivist-visual mind map teaching approach (CMA) and of a traditional teaching approach (TTA) on (a) the quality and richness of students’ knowledge structures and (b) TTA and CMA students’ perceptions of the extent that a constructivist learning environment (CLE) was created in their classes. The sample of the study consisted of six classes (140 Form 3 students of 13–15 years old) selected from a typical coeducational school in Brunei. Three classes (40 boys and 30 girls) were taught using the TTA while three other classes (41 boys and 29 girls) used the CMA, enriched with PowerPoint presentations. After the interventions (lessons on magnetism), the students in both groups were asked to describe in writing their understanding of magnetism accrued from the lessons. Their written descriptions were analyzed using flow map analyses to assess their content knowledge and its organisation in memory as evidence of cognitive structure. The extent of CLE was measured using a published CLE survey. The results showed that the cognitive structures of the CMA students were more extensive, thematically organised and richer in interconnectedness of thoughts than those of TTA students. Moreover, CMA students also perceived their classroom learning environment to be more constructivist than their counterparts. It is, therefore, recommended that teachers consider using the CMA teaching technique to help students enrich their understanding, especially for more complex or abstract scientific content.
This study, based on constructivist learning theory, examined how effectively preservice chemistr... more This study, based on constructivist learning theory, examined how effectively preservice chemistry teachers (N = 43) can be educated to think flexibly and to reorganize their thinking in a way that may complement diverse ways students approach the subject domain. The teacher's cognitive structure was assessed prior to and after a conceptual change intervention using flow-map narrative analyses. There was a significant change in the organization of the preservice teacher's narrative after the conceptual change intervention, including greater networking of ideas and more thematic development of the content. Hence, a conceptual change approach may be a useful way to educate teachers to be more responsive to student individual differences when planning and delivering science lessons.
Abstract The aim of this study was to compare the effects of constructivist-informed, technology-... more Abstract The aim of this study was to compare the effects of constructivist-informed, technology-rich learning environments and traditional learning environments on students' achievement. The sub-jects of the study were 115 Form V combined science students (16 ...
The suitability of the single vessel principle (performing all steps of an analytical procedure i... more The suitability of the single vessel principle (performing all steps of an analytical procedure in one vessel) for cold vapour atomic absorption spectrometric determination of mercury in biological solids was evaluated. The single vessel method gave a lower mean blank level with better precision, hence lower detection limits, as compared to the conventional method. The determination of total mercury in biological standard reference materials by the single vessel method also produced significantly higher mercury values and better precision than the conventional method. However, the mercury concentrations obtained in certified reference materials by the use of both methods were close to the mean certified values. Moreover, the use of the single vessel method is cost effective, rapid and environment friendly. The use of the single vessel technique is therefore recommended for accurate and reliable determination of mercury in biological solids.
- The aims of this study were to estimate the total amount of mercury released to the environment... more - The aims of this study were to estimate the total amount of mercury released to the environment during 60 years of gold mining (1867-1926) at Gympie, Queensland, Australia and to measure the mercury levels in soil samples surrounding the mining activity. We estimated that 1902 tonnes of mercury was released to the environment and about 1236 tonnes of which was released to the air. The mean mercury in the soil samples in the vicinity of the Scottish battery varied from 1.07 to 99.26 μg g-1 as compared to 0.075 μg g-1 as background mercury concentrations. The maximum mercury concentration measured in sediments of the Langton Gully was 6.12 μg g-1. These results show that large amount of mercury was used in this area during gold mining. Since mining is active in the area and Langton Gully flows into Mary River, we therefore, recommend that mercury concentration in air and fish should be monitored.
This study compared the effects of a constructivist-visual mind map teaching approach (CMA) and o... more This study compared the effects of a constructivist-visual mind map teaching approach (CMA) and of a traditional teaching approach (TTA) on (a) the quality and richness of students’ knowledge structures and (b) TTA and CMA students’ perceptions of the extent that a constructivist learning environment (CLE) was created in their classes. The sample of the study consisted of six classes (140 Form 3 students of 13–15 years old) selected from a typical coeducational school in Brunei. Three classes (40 boys and 30 girls) were taught using the TTA while three other classes (41 boys and 29 girls) used the CMA, enriched with PowerPoint presentations. After the interventions (lessons on magnetism), the students in both groups were asked to describe in writing their understanding of magnetism accrued from the lessons. Their written descriptions were analyzed using flow map analyses to assess their content knowledge and its organisation in memory as evidence of cognitive structure. The extent of CLE was measured using a published CLE survey. The results showed that the cognitive structures of the CMA students were more extensive, thematically organised and richer in interconnectedness of thoughts than those of TTA students. Moreover, CMA students also perceived their classroom learning environment to be more constructivist than their counterparts. It is, therefore, recommended that teachers consider using the CMA teaching technique to help students enrich their understanding, especially for more complex or abstract scientific content.
This study, based on constructivist learning theory, examined how effectively preservice chemistr... more This study, based on constructivist learning theory, examined how effectively preservice chemistry teachers (N = 43) can be educated to think flexibly and to reorganize their thinking in a way that may complement diverse ways students approach the subject domain. The teacher's cognitive structure was assessed prior to and after a conceptual change intervention using flow-map narrative analyses. There was a significant change in the organization of the preservice teacher's narrative after the conceptual change intervention, including greater networking of ideas and more thematic development of the content. Hence, a conceptual change approach may be a useful way to educate teachers to be more responsive to student individual differences when planning and delivering science lessons.
Abstract The aim of this study was to compare the effects of constructivist-informed, technology-... more Abstract The aim of this study was to compare the effects of constructivist-informed, technology-rich learning environments and traditional learning environments on students' achievement. The sub-jects of the study were 115 Form V combined science students (16 ...
The suitability of the single vessel principle (performing all steps of an analytical procedure i... more The suitability of the single vessel principle (performing all steps of an analytical procedure in one vessel) for cold vapour atomic absorption spectrometric determination of mercury in biological solids was evaluated. The single vessel method gave a lower mean blank level with better precision, hence lower detection limits, as compared to the conventional method. The determination of total mercury in biological standard reference materials by the single vessel method also produced significantly higher mercury values and better precision than the conventional method. However, the mercury concentrations obtained in certified reference materials by the use of both methods were close to the mean certified values. Moreover, the use of the single vessel method is cost effective, rapid and environment friendly. The use of the single vessel technique is therefore recommended for accurate and reliable determination of mercury in biological solids.
- The aims of this study were to estimate the total amount of mercury released to the environment... more - The aims of this study were to estimate the total amount of mercury released to the environment during 60 years of gold mining (1867-1926) at Gympie, Queensland, Australia and to measure the mercury levels in soil samples surrounding the mining activity. We estimated that 1902 tonnes of mercury was released to the environment and about 1236 tonnes of which was released to the air. The mean mercury in the soil samples in the vicinity of the Scottish battery varied from 1.07 to 99.26 μg g-1 as compared to 0.075 μg g-1 as background mercury concentrations. The maximum mercury concentration measured in sediments of the Langton Gully was 6.12 μg g-1. These results show that large amount of mercury was used in this area during gold mining. Since mining is active in the area and Langton Gully flows into Mary River, we therefore, recommend that mercury concentration in air and fish should be monitored.
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