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Samlafo, B.V, Bobobee, L.H, Quashie, E and Sarsah, L.A (2016). Cadmium, lead, arsenic and mercury levels in earthenware clay deposits at Vume, in the south Tongu District of Ghana, using Atomic Absorption Spectrophotometric Technique. International Journal of Current Research, 8,
Abstract
This paper screened for potentially harmful heavy metals such as As, Pb, Cd and Hg in earthenware clay deposits at Vume in the Volta region of Ghana using Atomic Absorption Spectrophotometric (AAS) technique. The concentrations of As in the clay samples ranged from 0.90 μg/g to 2.04 μg/g with a mean of 1.49 μg/g, and standard deviation of 0.47. Lead levels ranged from 2.85 μg/g to 4.08 μg/g with a mean of 3.67 μg/g, and a standard deviation of 0.38. Cadmium was below the detection limit of 0.002 μg/g in some samples: however, the levels measured ranged from 0.15 μg/g to 0.51 μg/g with a mean of 0.29 μg/g, and a standard deviation of 0. .13. The concentrations of mercury ranged from 0.18 μg/g to 0.69 μg/g with a mean of 0.53 μg/g, and a standard deviation of 0.15. The levels of Hg,Cd and Pb fell below their respective US EPA(1990) safe levels of 18.0 μg/g, 1.7 μg/g and 80.0 μg/g, except that of As which was above its US EPA(1990) safe level of 0.07 μg/g.The levels of Arsenic in the study area, though higher than the US EPA safe level, were comparable to the worldwide background level of 5 μg/g in soil. The precision and the accuracy of the AAS method were assessed via the use of reference material IAEA Soil-7. The values obtained for the various elements in the standard reference material (by analysing it with the AAS method) compared favourably well with the recommended values as Spearman’s correlation coefficient was + 0.96. The experimental values were within ±5% of the recommended value. The measurement precision determined by the relative standard deviation was within ±4%. With the exception of As levels which need some remediation, the quality of the clay at Vume was found to be generally good for the production of earthenware products.
This paper screened for potentially harmful heavy metals such as As, Pb, Cd and Hg in earthenware clay deposits at Vume in the Volta region of Ghana using Atomic Absorption Spectrophotometric (AAS) technique. The concentrations of As in the clay samples ranged from 0.90 μg/g to 2.04 μg/g with a mean of 1.49 μg/g, and standard deviation of 0.47. Lead levels ranged from 2.85 μg/g to 4.08 μg/g with a mean of 3.67 μg/g, and a standard deviation of 0.38. Cadmium was below the detection limit of 0.002 μg/g in some samples: however, the levels measured ranged from 0.15 μg/g to 0.51 μg/g with a mean of 0.29 μg/g, and a standard deviation of 0. .13. The concentrations of mercury ranged from 0.18 μg/g to 0.69 μg/g with a mean of 0.53 μg/g, and a standard deviation of 0.15. The levels of Hg,Cd and Pb fell below their respective US EPA(1990) safe levels of 18.0 μg/g, 1.7 μg/g and 80.0 μg/g, except that of As which was above its US EPA(1990) safe level of 0.07 μg/g.The levels of Arsenic in the study area, though higher than the US EPA safe level, were comparable to the worldwide background level of 5 μg/g in soil. The precision and the accuracy of the AAS method were assessed via the use of reference material IAEA Soil-7. The values obtained for the various elements in the standard reference material (by analysing it with the AAS method) compared favourably well with the recommended values as Spearman’s correlation coefficient was + 0.96. The experimental values were within ±5% of the recommended value. The measurement precision determined by the relative standard deviation was within ±4%. With the exception of As levels which need some remediation, the quality of the clay at Vume was found to be generally good for the production of earthenware products.
Hanson, R. (2015). Identifying studnets' alternative concepts in basic chemical bonding- A case study of teacher trainees' in the University of Education, Winneba. International Journal of Innovative Research and Development, 4,
Abstract
The study developed a diagnostic instrument to identify misconceptions that teacher trainees have of chemistry topics in relation to ionic and covalent bonding. Students’ initial ideas on these topics were collated through classroom discourse, Treagust’s (1988) and Tan and Treagust’s (1999) adapted diagnostic tests, concept maps and whole class interviews during the first week of interaction with teacher trainees in 2011. These data were used to produce 20 two-tier multiple choice items in four concept areas. The test had a Cronbach alpha reliability of 0.75. Item difficulties ranged from 0.12 to 0.65. Discrimination values ranged from 0.32-0.60. The diagnostic instrument was administered to 98 undergraduate teacher trainees in their second year of chemistry education at the University of Education, Winneba. The participants’ scores on each item were analysed by simple percentages to identify their misconceptions on basic chemical bonding and structure. The identified alternative concepts have been presented and discussed and possible teaching remedies suggested.
The study developed a diagnostic instrument to identify misconceptions that teacher trainees have of chemistry topics in relation to ionic and covalent bonding. Students’ initial ideas on these topics were collated through classroom discourse, Treagust’s (1988) and Tan and Treagust’s (1999) adapted diagnostic tests, concept maps and whole class interviews during the first week of interaction with teacher trainees in 2011. These data were used to produce 20 two-tier multiple choice items in four concept areas. The test had a Cronbach alpha reliability of 0.75. Item difficulties ranged from 0.12 to 0.65. Discrimination values ranged from 0.32-0.60. The diagnostic instrument was administered to 98 undergraduate teacher trainees in their second year of chemistry education at the University of Education, Winneba. The participants’ scores on each item were analysed by simple percentages to identify their misconceptions on basic chemical bonding and structure. The identified alternative concepts have been presented and discussed and possible teaching remedies suggested.
Hanson, R. (2015). Using microscience equipment to facilitate the study of qualitative analysis- A case study in an undergraduate class. European Journal of Basic and Applied Sciences, 2,
Abstract
Analytical chemistry is an important aspect of chemistry as it provides a lot of insight into the constituents and measurements of matter in all fields of science and medicine. Thus its study comprises the practice of qualitative and quantitative analysis which allows learners of science to have an experience of analytical work. However, the growing cost of science resources and the increasing numbers of students make the regular practice of such activities difficult. It drains the resources of schools which attempt to expose their students to practical work. In this interpretive study of quality micro analysis, 46 undergraduate teacher trainees participated in the use of microscience equipment in their forth semester for the identification of ions in solutions. Data to assess the feasibility of the intervention was done through observation, a questionnaire and a semi-structured interview. About 86% of the sample intimated that the micro activities were interactive, easy to use, yielded faster results and was fun to work with.
Analytical chemistry is an important aspect of chemistry as it provides a lot of insight into the constituents and measurements of matter in all fields of science and medicine. Thus its study comprises the practice of qualitative and quantitative analysis which allows learners of science to have an experience of analytical work. However, the growing cost of science resources and the increasing numbers of students make the regular practice of such activities difficult. It drains the resources of schools which attempt to expose their students to practical work. In this interpretive study of quality micro analysis, 46 undergraduate teacher trainees participated in the use of microscience equipment in their forth semester for the identification of ions in solutions. Data to assess the feasibility of the intervention was done through observation, a questionnaire and a semi-structured interview. About 86% of the sample intimated that the micro activities were interactive, easy to use, yielded faster results and was fun to work with.
Hanson, R., Kwarteng, T. A., & Antwi, V. (2015). Undergraduate chemistry teacher trainees' understanding of chemical phenomena. European Journal of Basic and Applied Sciences, 2,
Abstract
Knowledge about periodic trends enables students to understand and explain chemical phenomena which they encounter in everyday life and in formal settings such as in chemical activities in school laboratories. The case of first year undergraduate students’ understanding of chemical phenomena was assessed through an interpretive study. The study revealed that almost half of Ghanaian students at the entry point of tertiary teacher education had several alternative conceptions about periodicity in general and chemical phenomena in particular. The highest alternative conception was found to be on the electronegativities within a group of atoms and how they changed as well as how they affected polarity.
Knowledge about periodic trends enables students to understand and explain chemical phenomena which they encounter in everyday life and in formal settings such as in chemical activities in school laboratories. The case of first year undergraduate students’ understanding of chemical phenomena was assessed through an interpretive study. The study revealed that almost half of Ghanaian students at the entry point of tertiary teacher education had several alternative conceptions about periodicity in general and chemical phenomena in particular. The highest alternative conception was found to be on the electronegativities within a group of atoms and how they changed as well as how they affected polarity.
Sam, A., Niebert, K., Hanson, R., & Twumasi, A. K. (2015). The model of educational reconstruction: Scientists' and students' conceptual balances to improve the teaching of coordination chemistry in higher education. International Journal of Academic Research & Reflection, 3,
Abstract
The general knowledge of coordination chemistry, nomenclature and geometry was characterised by domain-specific students` conceptions as observed in this study. Based on the Model of Educational Reconstruction (MER), a clarification of coordination chemistry content structure was developed and made available for teaching. Generated conceptions from four (4) university-level science textbooks and students own ideas informed this clarification process. In this interpretive study, conceptual balances from scientists and fifteen (15) third year students of the University of Education, Winneba were brought into meaningful correspondences. Students` chemical drawings were analysed by qualitative content analysis and two (2) interventions adopted to be implemented in a subsequent study. Examples of how to bring students` conceptions vis-à-vis scientists` conceptions into balance have been discussed in this study.
The general knowledge of coordination chemistry, nomenclature and geometry was characterised by domain-specific students` conceptions as observed in this study. Based on the Model of Educational Reconstruction (MER), a clarification of coordination chemistry content structure was developed and made available for teaching. Generated conceptions from four (4) university-level science textbooks and students own ideas informed this clarification process. In this interpretive study, conceptual balances from scientists and fifteen (15) third year students of the University of Education, Winneba were brought into meaningful correspondences. Students` chemical drawings were analysed by qualitative content analysis and two (2) interventions adopted to be implemented in a subsequent study. Examples of how to bring students` conceptions vis-à-vis scientists` conceptions into balance have been discussed in this study.
Sam, A., Niebert, K., Hanson, R., & Aryeetey, C. (2016). Fusing Scientist and students' conceptual correspondences to improve the teaching of metal complex isomerism in higher education- An educational reconstructive process. International Journal of Academic Research & Reflection, 4,
Abstract
The study was conducted to explore Scientists’ and Students’ perspectives on metal complex isomerism. These correspondences formed a powerful grain for conceptual change in content oriented instruction for 15 third year chemistry major students at the University of Education, Winneba-Ghana. The interpretive case study was used to explore students’ responses on geometrical isomers of complexes. Based on the researchers` interpretation and the Model of Educational Reconstruction (MER), a clarification of geometrical isomerism in coordination chemistry content structure was developed. The generated conceptions from four (4) university-level textbooks and students, primarily informed this clarification process. These conceptions on metal-complex isomerism (geometrical) from scientists and students were brought into meaningful correspondences. All data were analysed by qualitative content analysis, addressing students` reasoning during a ten (10) week class sequence. The research afforded students access to use their constructed knowledge rather than being passive recipients of scientist-presented knowledge. The study discussed the relevance of geometrical isomerism in Higher Education (HE).
The study was conducted to explore Scientists’ and Students’ perspectives on metal complex isomerism. These correspondences formed a powerful grain for conceptual change in content oriented instruction for 15 third year chemistry major students at the University of Education, Winneba-Ghana. The interpretive case study was used to explore students’ responses on geometrical isomers of complexes. Based on the researchers` interpretation and the Model of Educational Reconstruction (MER), a clarification of geometrical isomerism in coordination chemistry content structure was developed. The generated conceptions from four (4) university-level textbooks and students, primarily informed this clarification process. These conceptions on metal-complex isomerism (geometrical) from scientists and students were brought into meaningful correspondences. All data were analysed by qualitative content analysis, addressing students` reasoning during a ten (10) week class sequence. The research afforded students access to use their constructed knowledge rather than being passive recipients of scientist-presented knowledge. The study discussed the relevance of geometrical isomerism in Higher Education (HE).
Hanson, R. (2016). Chemistry teacher trainees' perceptions of chemical equilibrium. The International Journal of Humanities & Social Studies, 4,
Abstract
Abstract This study investigated Ghanaian chemistry teacher trainees’ understanding about chemical equilibrium. A total of 104 second year undergraduate teacher trainees participated in the study. A test consisting of ten, 2-tiered multiple choice questions were used to collect data on the trainees’ conceptions about chemical equilibrium. The results from the study indicated that about 46% of the trainees had no conception about chemical equilibrium, while 32% had alternative conceptions, some of which had been identified in other studies in some parts of the world. About 50% of the trainees in this study, in addition, could not comprehend thoroughly on an abstract level. Neither could they appreciate the factors that influenced rates of chemical reactions, equilibrium shifts, nor their implications. In all, only about 23% of the participants understood the concept of chemical equilibrium. Eleven alternative concepts were identified. The use of interactive intervention was suggested for remediation.
Abstract This study investigated Ghanaian chemistry teacher trainees’ understanding about chemical equilibrium. A total of 104 second year undergraduate teacher trainees participated in the study. A test consisting of ten, 2-tiered multiple choice questions were used to collect data on the trainees’ conceptions about chemical equilibrium. The results from the study indicated that about 46% of the trainees had no conception about chemical equilibrium, while 32% had alternative conceptions, some of which had been identified in other studies in some parts of the world. About 50% of the trainees in this study, in addition, could not comprehend thoroughly on an abstract level. Neither could they appreciate the factors that influenced rates of chemical reactions, equilibrium shifts, nor their implications. In all, only about 23% of the participants understood the concept of chemical equilibrium. Eleven alternative concepts were identified. The use of interactive intervention was suggested for remediation.
Hanson, R. & Kwarteng, T. A. (2016). Using concept mapping to remediate chemistry teacher trainees' understanding of chemical phenomena- Before and after. International Journal of Scientific Research in Science and Technology, 2,
Abstract
Researchers have shown interest in how beginning chemistry teacher trainees can improve on their technological pedagogical content knowledge so as to be able to engage their students in concept-based and reflective activities. This is a task that trainees have to build up on their own by first mastering their content knowledge. This article focuses on 29 first year teacher trainees’ understanding of chemical phenomena and how their understanding could be improved through concept mapping. An intervention was designed to enhance their basic conceptions upon which other concepts could be built. We analysed concept maps on linkages of periodic properties and how they affect chemical bonding. Their submissions were analysed based on three categories of conceptual understanding. The results showed that their levels of conception improved after the concept mapping intervention.
Researchers have shown interest in how beginning chemistry teacher trainees can improve on their technological pedagogical content knowledge so as to be able to engage their students in concept-based and reflective activities. This is a task that trainees have to build up on their own by first mastering their content knowledge. This article focuses on 29 first year teacher trainees’ understanding of chemical phenomena and how their understanding could be improved through concept mapping. An intervention was designed to enhance their basic conceptions upon which other concepts could be built. We analysed concept maps on linkages of periodic properties and how they affect chemical bonding. Their submissions were analysed based on three categories of conceptual understanding. The results showed that their levels of conception improved after the concept mapping intervention.
Hanson, R. (2016). Ghanaian teacher trainees' conceptual understanding of stoichiometry. Journal of Education and e-Learning Research, 3,
Abstract
Chemical stoichiometry is a conceptual framework that encompasses other concepts such as the mole, writing of chemical equations in word and representative form, balancing of equations and the equilibrium concept. The underlying concepts enable students to understand relationships among entities of matter and required amounts for use when necessary. Success in this area of chemistry depends mainly on a student’s understanding of the concepts of the mole. An interpretive study on trainees’ conceptual understanding of chemical stoichiometry was carried out among 78 teacher trainees in their second year of study. The study comprised a combination of quantitative and qualitative interpretation of responses provided by trainees to stoichiometric questions. The interpretation indicated that their learning of stoichiometry was basically through the use of picket fence (factor label), undefined strategies and algorithm. The trainees were found to have more persistent problems with conceptual interpretation as they were not able to fully translate word problems into mathematical equations regardless their algorithmic underpinnings. Neither did they understand fully, the law of conservation of matter. Qualitative findings were found to be consistent with quantitative outputs. Keywords: Chemical change, Conceptual understanding, Non-limiting reactant, Percent yield, Stoichiometry, Theoretical yield.
Chemical stoichiometry is a conceptual framework that encompasses other concepts such as the mole, writing of chemical equations in word and representative form, balancing of equations and the equilibrium concept. The underlying concepts enable students to understand relationships among entities of matter and required amounts for use when necessary. Success in this area of chemistry depends mainly on a student’s understanding of the concepts of the mole. An interpretive study on trainees’ conceptual understanding of chemical stoichiometry was carried out among 78 teacher trainees in their second year of study. The study comprised a combination of quantitative and qualitative interpretation of responses provided by trainees to stoichiometric questions. The interpretation indicated that their learning of stoichiometry was basically through the use of picket fence (factor label), undefined strategies and algorithm. The trainees were found to have more persistent problems with conceptual interpretation as they were not able to fully translate word problems into mathematical equations regardless their algorithmic underpinnings. Neither did they understand fully, the law of conservation of matter. Qualitative findings were found to be consistent with quantitative outputs. Keywords: Chemical change, Conceptual understanding, Non-limiting reactant, Percent yield, Stoichiometry, Theoretical yield.
Hanson, R., Bobobee, L. H., Twumasi, K. A., & Antwi, V. (2015). . Designing micro chemistry experiments for teacher trainees in a university, 3,
Abstract
Micro chemistry experimentation has come to reduce the usual traditional experimentation through miniature activities. In addition it has reduced activity time and the cost of resources significantly and yet provided personal hands-on experiences for learners. This study presents the design of micro chemistry experimentation for some quantitative and qualitative inorganic chemistry topics for first year undergraduate teacher trainees as well as to introduce a motivating way to teach and conduct chemistry activities. It basically set out to explore the designed low-cost practical approach that could contribute to improved laboratory practice in Ghana, in view of resource, time, and space constraints in a teaching institution. Overall findings showed that the micro chemistry approach made chemistry lessons interesting, interactive, and enabled learners to acquire many learning skills by themselves. Keywords: Comboplate, wells, microchemistry kit, micro quantity, macro quantity.
Micro chemistry experimentation has come to reduce the usual traditional experimentation through miniature activities. In addition it has reduced activity time and the cost of resources significantly and yet provided personal hands-on experiences for learners. This study presents the design of micro chemistry experimentation for some quantitative and qualitative inorganic chemistry topics for first year undergraduate teacher trainees as well as to introduce a motivating way to teach and conduct chemistry activities. It basically set out to explore the designed low-cost practical approach that could contribute to improved laboratory practice in Ghana, in view of resource, time, and space constraints in a teaching institution. Overall findings showed that the micro chemistry approach made chemistry lessons interesting, interactive, and enabled learners to acquire many learning skills by themselves. Keywords: Comboplate, wells, microchemistry kit, micro quantity, macro quantity.
