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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Understanding Climate Change and Sea Level: A Case Study of Middle School Student Comprehension and An Evaluation of Tide Gauges off the Panama Canal in the Pacific Ocean and Caribbean Sea

Millan-Otoya, Juan Carlos 06 November 2015 (has links)
The present study had two main objectives. The first was to determine the degree of understanding of climate change, sea level and sea level rise among middle school students. Combining open-ended questions with likert-scaled questions, we identified student conceptions on these topics in 86 students from 7th and 8th grades during 2012 and 2013 before and after implementing a Curriculum Unit (CU). Additional information was obtained by adding drawings to the open-ended questions during the second year to gauge how student conceptions varied from a verbal and a visual perspective. Misconceptions were identified both pre- and post-CU among all the topics taught. Students commonly used climate and climate change as synonyms, sea level was often defined as water depth, and several students failed to understand the complexities that determine changes in sea level due to wind, tides, and changes in sea surface temperature. In general, 8th grade students demonstrated a better understanding of these topics, as reflected in fewer apparent misconceptions after the CU. No previous study had reported such improvement. This showed the value of implementing short lessons. Using Piaget’s theories on cognitive development, the differences between 7th and 8th grade students reflect a transition to a more mature level which allowed students to comprehend more complex concepts that included multiple variables. The second objective was to determine if the frequency of sea level maxima not associated with tides over the last 100 years increased in two tide gauges located on the two extremes of the Panama canal, i.e. Balboa in the Pacific Ocean and Cristobal in the Caribbean Sea. These records were compared to time series of regional sea surface temperature, wind speed, atmospheric pressure, and El Niño-Southern Oscillation (ENSO), to determine if these played a role as physical drivers of sea level at either location. Neither record showed an increase in the frequency of sea level maxima events. No parameter analyzed explained variability in sea level maxima in Cristobal. There was a significant correlation between the zonal component of the wind and sea level at Balboa for the early record (r=0.153; p-value0.05). There was a clear relationship between sea level maxima and ENSO. 70% of the years with higher counts of higher sea level events corresponded to El Niño years. A randomization test with 1000 iterations, shuffling the El Niño years, showed most of these randomizations grouped between 14-35% of the events occurring during a randomized El Niño year. In no iteration did the percentage of events that occurred during El Niño years rise above 65%. The correlation with zonal wind and the probable correlation with sea surface temperature can be linked via ENSO, since ENSO is associated with changes in the strength of the Trade Winds and positive anomalies in the sea surface temperature of the tropical Pacific Ocean.
2

Conceptual change through cognitive perturbation using simulations in electricity and magnetism : a case study in Ambo University, Ethiopia

Bekele Gashe Dega 11 1900 (has links)
The purpose of this study was to investigate physics undergraduate students’ conceptual change in the concepts of electric potential and energy (EPE) and electromagnetic induction (EMI). Along with this, categorization of students’ conceptions was done based on students’ epistemological and ontological descriptions of these concepts. In addition, the effect of cognitive perturbation using physics interactive simulations (CPS) in relation to cognitive conflict using physics interactive simulations (CCS) was investigated. A pragmatic mixed methods approach was used in a quasi-experimental design. Data were collected by using the modified Diagnostic Exam of Electricity and Magnetism (DEEM), focus group discussions (FGD) and concept maps (CM). Framework analysis was conducted separately on FGD and CM qualitative data to categorize students’ conceptions while concentration analysis was used to categorize students’ responses to the modified DEEM into three levels, during pre and post intervention. In the qualitative results, six categories of alternative conceptions (naive physics, lateral alternative conceptions, ontological alternative conceptions, Ohm’s P-Primes/ P-Primes, mixed conceptions and loose ideas) and two categories of conceptual knowledge (hierarchical and relational) were identified. The alternative conceptions were less frequently and inconsistently revealed within and across the categories. It was concluded that the categories have common characteristics of diversified distribution of alternative conceptions and multiple alternative conceptions of specific concepts within and across the categories. Most of the categories found in pre intervention persisted in post intervention, but with a lesser percentage extensiveness of categories of alternative conceptions in the CPS than in the CCS class and more percentage extensiveness of categories of conceptual knowledge in the CPS than in the CCS class. ANCOVA was separately conducted on the scores of 45 students on the modified DEEM and CM tests to compare the effectiveness of the CCS and CPS. The results showed a significant difference between the two classes of the post test scores on the DEEM test, (1, 36) = 4.66, p=0.04 and similarly, on the CM test, (1, 31) = 8.33, p=0.007. Consequently, it was concluded that there is a statistically significant difference between CPS and CCS in changing students’ alternative conceptions towards scientific conceptions favoring CPS. To characterize and compare students’ conceptual change of both treatment classes, Hake’s average normalized gain <g> from pre to post scores (the modified DEEM and the CM) were analyzed. Finally, it is suggested that in abstract conceptual areas of EM, cognitive perturbation through interactive simulations is more effective than cognitive conflict through interactive simulations in facilitating conceptual change, and, thus, should guide classroom instruction in the area. Furthermore, recommendations are also suggested for guiding future research in this area. / Science and Technology Education / D. Phil. (Mathematics, Science and Technology Education (Physics Education))
3

Conceptual change through cognitive perturbation using simulations in electricity and magnetism : a case study in Ambo University, Ethiopia

Bekele Gashe Dega 11 1900 (has links)
The purpose of this study was to investigate physics undergraduate students’ conceptual change in the concepts of electric potential and energy (EPE) and electromagnetic induction (EMI). Along with this, categorization of students’ conceptions was done based on students’ epistemological and ontological descriptions of these concepts. In addition, the effect of cognitive perturbation using physics interactive simulations (CPS) in relation to cognitive conflict using physics interactive simulations (CCS) was investigated. A pragmatic mixed methods approach was used in a quasi-experimental design. Data were collected by using the modified Diagnostic Exam of Electricity and Magnetism (DEEM), focus group discussions (FGD) and concept maps (CM). Framework analysis was conducted separately on FGD and CM qualitative data to categorize students’ conceptions while concentration analysis was used to categorize students’ responses to the modified DEEM into three levels, during pre and post intervention. In the qualitative results, six categories of alternative conceptions (naive physics, lateral alternative conceptions, ontological alternative conceptions, Ohm’s P-Primes/ P-Primes, mixed conceptions and loose ideas) and two categories of conceptual knowledge (hierarchical and relational) were identified. The alternative conceptions were less frequently and inconsistently revealed within and across the categories. It was concluded that the categories have common characteristics of diversified distribution of alternative conceptions and multiple alternative conceptions of specific concepts within and across the categories. Most of the categories found in pre intervention persisted in post intervention, but with a lesser percentage extensiveness of categories of alternative conceptions in the CPS than in the CCS class and more percentage extensiveness of categories of conceptual knowledge in the CPS than in the CCS class. ANCOVA was separately conducted on the scores of 45 students on the modified DEEM and CM tests to compare the effectiveness of the CCS and CPS. The results showed a significant difference between the two classes of the post test scores on the DEEM test, (1, 36) = 4.66, p=0.04 and similarly, on the CM test, (1, 31) = 8.33, p=0.007. Consequently, it was concluded that there is a statistically significant difference between CPS and CCS in changing students’ alternative conceptions towards scientific conceptions favoring CPS. To characterize and compare students’ conceptual change of both treatment classes, Hake’s average normalized gain <g> from pre to post scores (the modified DEEM and the CM) were analyzed. Finally, it is suggested that in abstract conceptual areas of EM, cognitive perturbation through interactive simulations is more effective than cognitive conflict through interactive simulations in facilitating conceptual change, and, thus, should guide classroom instruction in the area. Furthermore, recommendations are also suggested for guiding future research in this area. / Science and Technology Education / D. Phil. (Mathematics, Science and Technology Education (Physics Education))

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