Browsing by Author "Taylor, Dale"

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    Open Access
    Probing student engagement with size and distance in introductory astronomy
    (2022) Makwela, Tshiamiso Neo; Allie, Saalih; Taylor, Dale; Blyth, Sarah
    Astronomy Education Research has shown that students have many challenges when it comes to understanding key concepts in Astronomy. Amongst these is a poor understanding of astronomical scales. Recently for example, both sizes and distances have been shown to present similar difficulties to students in both South Africa and Norway. It is difficult to attribute the findings simply to inadequate teaching due to the significant differences between the two countries with regard to language, culture, and the type of science teaching. It has, therefore, been suggested that since astronomical sizes and distances are beyond immediate human experience the explanation might in fact lie at a deeper cognitive level. The present thesis is aimed at exploring the link between astronomical sizes and distances as well as cognition. Part I The thesis focuses on investigating students' understanding of sizes and distances in astronomy. This was done by probing student notions of astronomical scales, using the size and distance questions from the Introductory Astronomy Questionnaire (IAQ), the instrument which led to the original findings noted previously. These questions were administered before and after a specially structured teaching intervention on sizes and distances. The results of this study in 2018 were found to be (a) in agreement with similar studies previously reported in South Africa and Norway, namely, that both sizes and distances in astronomy were poorly understood in both contexts and (b) that the teaching intervention was least effective for distances. Based on the findings above, the focus of the thesis shifted to a more fine-grained investigation of how students conceived of distances, as they increased from "human scale" to "beyond human scale". The study was carried out using the Grounded Theory Method (GTM). Data were generated by prompting written explanations from introductory astronomy students on how they engaged with three distances two of which may be considered to be within human experience while the third lies beyond the realm of direct experience. The distances used were 7 metres, 100 kilometres and the distance to the moon. The second distance was partly informed by the idea that we often communicate large distances to each other in terms of time. In addition, the framing of the questions excluded the possibility of visual explanations. The questions were administered to a cohort of introductory astronomy students at the University of Cape Town in 2019. A grounded analysis of the student responses was carried out to identify key ideas. The categories that emerged from the analysis showed clear evidence of students using different, unconnected types of explanations rather than simple extrapolations of one idea. A conceptual transition was identified relative to the body position of the respondents: body calibration and self-propelled body motion (or journeying). What was striking was that time was rarely mentioned explicitly. The way in which students expressed themselves was assumed to be an expression of the way in which they were thinking about different distance domains and suggestive of the cognitive perspective offered by "Embodied Cognition". Of particular interest was that nonstatic explanations were centered around the notion of a journey, and one of the key "thinking templates" in Embodied Cognition; the SOURCE-PATH-GOAL "Image Schema". Part II of the thesis summarizes key elements of Embodied Cognition that are pertinent to the present work and describes a pilot activity for teaching astronomical distances based on this account. Part II Theories of cognition can roughly be divided into two camps: those that assume that thinking is a "mentalese activity" involving symbolic manipulation. Most importantly, these symbolic elements are "amodal" in that they are not derived from the sensory modalities. On the other hand, Embodied Cognition assumes that these symbols arise from the sensory modalities, hence all thinking arises from bodily experience and its interactions with the environment in infancy. While there are several strands that feed into Embodied Cognition, of direct interest to the present work is that of Cognitive Linguistics and the notion of Conceptual Metaphor. In this view metaphors are not regarded as (mere) linguistic devices but as conceptual expressions that reflect cognitive schematic structures that relate to the bodily infant experience. These cognitive schematic structures or "Image Schemas" arise from repeated bodily actions repeatedly activating particular neural networks and form the basic building blocks of all abstract thought. A fair amount of such Image Schemas (or "thinking templates") have been identified of which the SOURCE-PATH-GOAL resonates most clearly with the data described earlier. This Image Schema comes about in infancy when a child learns that a toy on the far side of a room cannot be reached by grasping only but that moving the body from one place to another (crawling) is required. This is the basis of "Life is Journey or the Ph.D. Journey", for example. Another aspect of Embodied Cognition holds that understanding involves a mental simulation using the cognitive resources that are activated at the time. In order to see if activating the SPG / Journey "thinking template" prior to engaging with the teaching material would help in comprehending astronomical distances a two-part teaching activity (A and B) was developed around the notion of a journey. Part A was presented to the students as 'Journey to the observable edge of the UNIVERSE along UNIVERSity avenue" and required students to walk the length of the campus in a structured manner that is described in detail in the thesis. Part B, engagement with the teaching material, was carried out immediately afterwards in the Main Hall of the University. Thus, the thinking behind the two-part activity, piloted in 2020 just prior to Covid related lockdown, was that "journey" cognitive resources would be activated by the experience and would therefore be used in engaging with the teaching material regarding astronomical distances. Student evaluations were gathered in order to probe how students had engaged with the activity, including if any of the resources associated with journeying were expressed. A post-test ranking task showed that while results were mixed relative to previous studies overall there was a marked improvement for the present cohort. In summary the work shows clearly that there were two different modes of thinking about distances (i) based on counting and (2) based on the notion of the journey/journey-ing. Results were interpreted as the activation of schema described by embodied cognition. The difficulty that students experienced with astronomical distances was attributed to the lack of activating the Source-Path-Goal schema. In order to see whether there was a way to activate the Source-Path-Goal schema, an activity involving students walking was designed. The outcomes from the activity, indicated promising results with regard to student engagement with astronomical distance.
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    The story of a physiclal science curriculum: transformation or transmutation?
    (Taylor & Francis, 2012) Nakedi, Mpunki; Taylor, Dale; Mundalamo, Fhatuwani; Rollnick, Marissa; Mokeleche, Maebeebe
    Recently Curriculum and Assessment Policy Statements (CAPS) were introduced in South Africa in response to confusion precipitated by previous curriculum documents. The purpose of this paper is to explore that confusion in the subject 'Physical Sciences' and consider the nature of the transformation from the previous curriculum by looking at curriculum documents and examination papers. We present a two phase curriculum change model which suggests that congruency between curriculum documents and examinations is critical for effective curriculum change. We analyse the pre-CAPS curriculum, the National Curriculum Statement (NCS), on its own terms by using the stated outcomes as our reference point. Our analysis reveals that the weighting and conceptualization of the outcomes shifted through successive documents, which undermined congruency between the documents and meant that content-oriented science masqueraded as inquiry-oriented science. This led to a retreat from the original vision of weighting skills and relevance equally with content. The examinations took this retreat a step further. Evidence of the retreat is that the nature of the questions asked in the 2008 examinations on the NCS was similar to that of the 2007 examinations on the previous curriculum which had not changed since apartheid. However, in the NCS examinations there was a small shift towards contextualisation and inquiry oriented science. The retreat means the vision of transformation which was the rationale for the NCS curriculum was eroded – instead of transformation, there was transmutation back to the old apartheid curriculum. The Physical Sciences CAPS cements the retreat and creates new confusion by changing the syllabus again without signposting the change.
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    The Use of Combinations of Chemosensitisers to Reverse Chloroquine Resistance in Mice infected with Malaria
    (2012) Taylor, Dale; Smith, Peter
    Although several dozen different compounds are able to transiently alter chloroquine resistance via chemosensitisation, the phenomenon has never evolved beyond laboratory practice as a result of in vivo difficulties. Chemosensitising compounds either need to be administered at doses which are toxic to the host in order to reverse resistance, or the drug is so highly bound to serum proteins that there is an insufficient circulating quantity available to restore sensitivity. Nine chemosensitisers were evaluated in vitro against several resistant isolates of the malaria parasite in order to develop a cocktail treatment of three compounds which could reverse resistance additively or synergistically when used at low doses with chloroquine. This would bypass any toxicity issues which might arise from the use of a high dose of a single agent. Six of the chemosensitisers were selected for combination into six different cocktails which were tested in vitro. Each cocktail contained one antidepressant, one antihistamine and one antipsychotic. Low doses of each drug were able to alter resistance to a small extent singly and in combination; this was shown by determining the effect of drugs and cocktails on both chloroquine transport using radiolabelled chloroquine, and chloroquine efficacy using the lactate dehydrogenase assay for parasite viability. The reversal activity was shown to be additive in the cocktail treatments and not synergistic, and was highly dose-dependent. There was no direct correlation between the change in chloroquine transport and the extent of resistance reversal. The chemosensitisers' effect on chloroquine transport was evaluated in a mouse model of malaria and shown to be similar to that seen against cultured human parasites; following this, the cocktails were tested for efficacy in mice infected with chloroquine-resistant malaria. Five of the six cocktails were able to significantly alter parasite survival in the mice in conjunction with a low dose of chloroquine. Drug levels in the mice were quantified via mass spectrometry and liquid chromatography in order to correlate the efficacy data. One of the compounds in the failed treatment was shown to circulate at low levels in the animals and this is possibly why that treatment, although effective in vitro, did not yield a result in vivo.