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- Genre: Masters Thesis
Description
The under-representation of women in science, technology, engineering and mathematics (STEM) fields indicates the presence of gender related barriers that impacted the persistence of women in science and engineering doctoral studies. The purpose of this study was to investigate the barriers of women doctoral students in STEM fields which identified supporting factors for them as well. This study also tried to determine if there was any difference in perceiving barriers among three disciplines - engineering, life sciences and natural sciences. An online questionnaire (19 Likert-type questions and one open-ended question) was sent to women STEM doctoral students studying at the Arizona State University (ASU). Questions were based on some factors which might act as obstacles or supports during their doctoral studies. Both quantitative and qualitative analyses were conducted. Factors such as work-life balance, time-management, low self-confidence, lack of female role model, fewer numbers of women in science and engineering classes, and male dominated environment revealed as significant barriers according to both the analyses but factors such as difficulty with the curriculum, gender discrimination, and two-career problem were chosen as barriers only in the free response question. Positive treatment from advisor, family support, availability of funding, and absence of sexual harassment assisted these women continuing their PhD programs at ASU. However, no significant difference was observed with respect to perceiving barriers among the three groups mentioned above. Recommendations for change in science and engineering curricula and active recruitment of female faculty are discussed to reduce or at best to remove the barriers and how to facilitate participation and retention of more women in STEM fields especially at the doctoral level.
ContributorsChaudhuri, Dola (Author) / Baker, Dale (Thesis advisor) / Sandlin, Jennifer (Committee member) / Edwards, Vicki (Committee member) / Arizona State University (Publisher)
Created2011
Description
The nature of science (NOS) is included in the National Science Education Standards and is described as a critical component in the development of scientifically literate students. Despite the significance of NOS in science education reform, research shows that many students continue to possess naïve views of NOS. Explicit and reflective discussion as an instructional approach is relatively new in the field of research in NOS. When compared to other approaches, explicit instruction has been identified as more effective in promoting informed views of NOS, but gaps in student understanding still exist. The purpose of this study was to deepen the understanding of student learning of NOS through the investigation of two variations of explicit instruction. The subjects of the study were two seventh grade classes taught by the same classroom teacher. One class received explicit instruction of NOS within a plate tectonics unit and the second class received explicit instruction of NOS within a plate tectonics unit plus supporting activities focused on specific aspects of NOS. The instruction time for both classes was equalized and took place over a three week time period. The intention of this study was to see if the additional NOS activities helped students build a deeper understanding of NOS, or if a deep understanding could be formed solely through explicit and reflective discussion within content instruction. The results of the study showed that both classes progressed in their understanding of NOS. When the results of the two groups were compared, the group with the additional activities showed statistically significant gains on two of the four aspects of NOS assessed. These results suggest that the activities may have been valuable in promoting informed views, but more research is needed in this area.
ContributorsMelville, Melissa (Author) / Luft, Julie (Thesis advisor) / Baker, Dale (Committee member) / Brem, Sarah (Committee member) / Arizona State University (Publisher)
Created2011
Description
Conceptual change has been a large part of science education research for several decades due to the fact that it allows teachers to think about what students' preconceptions are and how to change these to the correct scientific conceptions. To have students change their preconceptions teachers need to allow students to confront what they think they know in the presence of the phenomena. Students then collect and analyze evidence pertaining to the phenomena. The goal in the end is for students to reorganize their concepts and change or correct their preconceptions, so that they hold more accurate scientific conceptions. The purpose of this study was to investigate how students' conceptions of the Earth's surface, specifically weathering and erosion, change using the conceptual change framework to guide the instructional decisions. The subjects of the study were a class of 25 seventh grade students. This class received a three-week unit on weathering and erosion that was structured using the conceptual change framework set by Posner, Strike, Hewson, and Gertzog (1982). This framework starts by looking at students' misconceptions, then uses scientific data that students collect to confront their misconceptions. The changes in students' conceptions were measured by a pre concept sketch and post concept sketch. The results of this study showed that the conceptual change framework can modify students' preconceptions of weathering and erosion to correct scientific conceptions. There was statistical significant difference between students' pre concept sketches and post concept sketches scores. After examining the concept sketches, differences were found in how students' concepts had changed from pre to post concept sketch. Further research needs to be done with conceptual change and the geosciences to see if conceptual change is an effective method to use to teach students about the geosciences.
ContributorsTillman, Ashley (Author) / Luft, Julie (Thesis advisor) / Middleton, James (Committee member) / Semken, Steven (Committee member) / Arizona State University (Publisher)
Created2011
Description
Meter-resolution topography gathered by LiDAR (Light Detection and Ranging) has become an indispensable tool for better understanding of many surface processes including those sculpting landscapes that record information about earthquake hazards for example. For this reason, and because of the spectacular representation of the phenomena that these data provide, it is appropriate to integrate these data into Earth science educational materials. I seek to answer the following research question: "will using the LiDAR topography data instead of, or alongside, traditional visualizations and teaching methods enhance a student's ability to understand geologic concepts such as plate tectonics, the earthquake cycle, strike-slip faults, and geomorphology?" In order to answer this question, a ten-minute introductory video on LiDAR and its uses for the study of earthquakes entitled "LiDAR: Illuminating Earthquake Hazards" was produced. Additionally, LiDAR topography was integrated into the development of an undergraduate-level educational activity, the San Andreas fault (SAF) earthquake cycle activity, designed to teach introductory Earth science students about the earthquake cycle. Both the LiDAR video and the SAF activity were tested in undergraduate classrooms in order to determine their effectiveness. A pretest and posttest were administered to introductory geology lab students. The results of these tests show a notable increase in understanding LiDAR topography and its uses for studying earthquakes from pretest to posttest after watching the video on LiDAR, and a notable increase in understanding the earthquake cycle from pretest to posttest using the San Andreas Fault earthquake cycle exercise. These results suggest that the use of LiDAR topography within these educational tools is beneficial for students when learning about the earthquake cycle and earthquake hazards.
ContributorsRobinson, Sarah Elizabeth (Author) / Arrowsmith, Ramon (Thesis advisor) / Reynolds, Stephen J. (Committee member) / Semken, Steven (Committee member) / Arizona State University (Publisher)
Created2011
Description
The spectacular geological panoramas of Grand Canyon National Park (GCNP) motivate the curiosity of visitors about geology. However, there is little research on how well these visitors understand the basic geologic principles on display in the Canyon walls. The new Trail of Time (ToT) interpretative exhibit along the South Rim uses Grand Canyon vistas to teach these principles. Now being visited by thousands daily, the ToT is a uniquely valuable setting for research on informal learning of geologic time and other basic geologic concepts. At the ToT, visitors are not only asked to comprehend a linear timeline, but to associate it with the strata exposed in the walls of the Canyon. The research addressed two primary questions: (1) how do visitors of the National Park use elements of the geologic landscape of the Grand Canyon to explain fundamental principles of relative geologic time? and (2) how do visitors reconcile the relationship between the horizontal ToT timeline and the vertical encoding of time in the strata exposed in the Canyon walls? Semi-structured interviews tracked participants' understanding of the ToT exhibit and of basic principles of geologic time. Administering the verbal analysis method of Chi (1997) to the interview transcripts, the researcher identified emergent themes related to how the respondents utilized the landscape to answer interview questions. Results indicate that a majority of respondents are able to understand principles of relative geologic time by utilizing both the observed and inferred landscape of Grand Canyon. Results also show that by applying the same integrated approach to the landscape, a majority of respondents are able to reconcile stratigraphic time with the horizontal ToT timeline. To gain deeper insight into the cognitive skills activated to correctly understand geologic principles the researcher used Dodick and Orion's application of Montangero's (1996) diachronic thinking model to code responses into three schemes: (1) transformation, (2) temporal organization, and (3) interstage linkage. Results show that correct responses required activation of the temporal organization scheme or the more advanced interstage linkage scheme. Appropriate application of these results can help inform the development of future outdoor interpretive geoscience exhibits.
ContributorsFrus, Rebecca (Author) / Semken, Steven (Thesis advisor) / Baker, Dale (Committee member) / Farmer, Jack (Committee member) / Arizona State University (Publisher)
Created2011
Description
Writing scientific explanations is increasingly important, and today's students must have the ability to navigate the writing process to create a persuasive scientific explanation. One aspect of the writing process is receiving feedback before submitting a final draft. This study examined whether middle school students benefit more in the writing process from receiving peer feedback or teacher feedback on rough drafts of scientific explanations. The study also looked at whether males and females reacted differently to the treatment groups. And it examined if content knowledge and the written scientific explanations were correlated. The study looked at 38 sixth and seventh-grade students throughout a 7-week earth science unit on earth systems. The unit had six lessons. One lesson introduced the students to writing scientific explanations, and the other five were inquiry-based content lessons. They wrote four scientific explanations throughout the unit of study and received feedback on all four rough drafts. The sixth-graders received teacher feedback on each explanation and the seventh-graders received peer-feedback after learning how to give constructive feedback. The students also took a multiple-choice pretest/posttest to evaluate content knowledge. The analyses showed that there was no significant difference between the group receiving peer feedback and the group receiving teacher feedback on the final drafts of the scientific explanations. There was, however, a significant effect of practice on the scores of the scientific explanations. Students wrote significantly better with each subsequent scientific explanation. There was no significant difference between males and females based on the treatment they received. There was a significant correlation between the gain in pretest to posttest scores and the scientific explanations and a significant correlation between the posttest scores and the scientific explanations. Content knowledge and written scientific explanations are related. Students who wrote scientific explanations had significant gains in content knowledge.
ContributorsLange, Katie (Author) / Baker, Dale (Thesis advisor) / Megowan, Colleen (Committee member) / Middleton, James (Committee member) / Arizona State University (Publisher)
Created2011
Description
ABSTRACT The accretion of juvenile island-arc lithosphere by convergent tectonism during the Paleoproterozoic, in conjunction with felsic volcanism, resulted in the assembly, ductile to partial brittle deformation, uplift, and northwest-directed thrusting of rocks in the McDowell Mountains region and adjacent areas in the Mazatzal Orogenic belt. Utilizing lithologic characteristics and petrographic analysis of the Proterozoic bedrock, a correlation to the Alder series was established, revising the stratigraphic sequences described by earlier works. The central fold belt, composed of an open, asymmetric syncline and an overturned, isoclinal anticline, is cut by an axial-plane parallel reactivated thrust zone that is intruded by a deformed Paleoproterozoic mafic dike. Finite strain analyses of fold geometries, shear fabrics, foliations, fold vergence, and strained clasts point to Paleoproterozoic northwest-directed thrusting associated with the Mazatzal orogen at approximately 1650 million years ago. Previous studies constrained the regional P-T conditions to at least the upper andalusite-kyanite boundary at peak metamorphic conditions, which ranged from 4-6 kilobars and 350-450⁰ Celsius, although the plasticity of deformation in a large anticlinal core suggests that this represents the low end of the P-T conditions. Subsequent to deformation, the rocks were intruded by several granitoid plutons, likely of Mesoproterozoic age (1300-1400 Ma). A detailed analysis of Proterozoic strain solidly places the structure of the McDowell Mountains within the confines of the Mazatzal Orogeny, pending any contradictory geochronological data.
ContributorsVance, Brad (Author) / Reynolds, Stephen J. (Thesis advisor) / Semken, Steven (Committee member) / Stump, Edmund (Committee member) / Arizona State University (Publisher)
Created2012
Description
New quadrangle-scale geologic mapping of the western part of the Date Creek Mountains (DCM) in west-central Arizona has revealed new insights into the geologic units, structures, and geologic history. Three U-Pb dates also provide surprising new information about the age and spatial relationships of the DCM as well as implications for the tectonics of the area. Paleoproterozoic metamorphic rocks in the central part of the DCM are presumably correlative with the Yavapai schist exposed in other parts of the Arizona Transition Zone. A granite formerly assigned to the Paleoproterozoic was subdivided into megacrystic and fine-grained units and hosts a set of previously undescribed subvertical felsic dikes. A new U-Pb date of the fine-grained phase has shown that unit to be Jurassic. The Mesoproterozoic Granite of Joshua Tree Parkway (Bryant, 1995), which also has fine-grained and megacrystic phases, displays a subhorizontal interunit contact suggestive of vertical stacking of individual intrusions. The age of another granitic pluton previously thought to be Laramide has been revised to Jurassic with the new U-Pb dates. Multiple noncontinuous sections of Tertiary volcanic rocks cover parts of the western end of the range with a combined thickness of at least 500 m. Tertiary basin fill abuts the northern and western edges of the range and perched remnants of the fill in the mountains suggest a former thickness of at least 100 m more than today. Quaternary alluvium is present in the drainages and covers the slopes south of the mountains. In addition to the felsic dikes, mafic and pegmatite dikes are also present. Two major structures are exposed in the study area: a roughly north-trending graben at the western end of the range and a probable normal fault which cuts northwest-southeast across the DCM and displays a zone of brittle deformation up to a few hundred meters wide. The orientation of the normal fault mirrors that of other similar faults in the area and is considered to be the result of regional tectonics activity, while the graben may owe its existence to movement on an underlying low-angle detachment fault.
ContributorsEddy, David (Author) / Reynolds, Stephen J. (Thesis advisor) / Arrowsmith, J R (Committee member) / Semken, Steven (Committee member) / Arizona State University (Publisher)
Created2012
Description
The North American Monsoon (NAM) is characterized by high inter- and intra-seasonal variability, and potential climate change effects have been forecasted to increase this variability. The potential effects of climate change to the hydrology of the southwestern U.S. is of interest as they could have consequences to water resources, floods, and land management. I applied a distributed watershed model, the Triangulated Irregular Network (TIN)-based Real-time Integrated Basin Simulator (tRIBS), to the Beaver Creek basin in Arizona. This sub-basin of the Verde River is representative of the regional topography, land cover, and soils distribution. As such, it can serve to illustrate the utility of distributed models for change assessment studies. Model calibration was performed utilizing radar-based NEXRAD data, and comparisons were done to two additional sources of precipitation data: ground-based stations and the North American Land Data Assimilation System (NLDAS). Comparisons focus on the spatiotemporal distributions of precipitation and stream discharge. Utilizing the calibrated model, I applied scenarios from the HadCM3 General Circulation Model (GCM) which was dynamically downscaled by the Weather Research and Forecast (WRF) model, to refine the representation of Arizona's regional climate. Two time periods were examined, a historical 1990-2000 and a future 2031-2040, to evaluate the hydrologic consequence in the form of differences and similarities between the decadal averages for temperature, precipitation, stream discharge and evapotranspiration. Results indicate an increase in mean air temperature over the basin by 1.2 ºC. The average decadal precipitation amounts increased between the two time periods by 2.4 times that of the historical period and had an increase in variability that was 3 times the historical period. For the future period, modeled streamflow discharge in the summer increased by a factor of 3. There was no significant change in the average evapotranspiration (ET). Overall trends of increase precipitation and variability for future climate scenarios have a more significant effect on the hydrologic response than temperature increases in the system during NAM in this study basin. The results from this study suggest that water management in the Beaver Creek will need to adapt to higher summer streamflow amounts.
ContributorsHawkins, Gretchen (Author) / Vivoni, Enrique R. (Thesis advisor) / Semken, Steven (Committee member) / Mays, Larry W. (Committee member) / Arizona State University (Publisher)
Created2012
Description
ABSTRACT Research has shown that students from elementary school to college have major misconceptions about the nature of science. While an appropriate understanding of the nature of science has been an objective of science education for a century, researchers using a variety of instruments, continue to document students' inadequate conceptions of what science is and how it operates as an enterprise. Current research involves methods to improve student understanding of the nature of science. Students often misunderstand the creative, subjective, empirical, and tentative nature of science. They do not realize the relationship between laws and theories, nor do they understand that science does not follow a prescribed method. Many do not appreciate the influence culture, society, and politics; nor do they have an accurate understanding of the types of questions addressed by science. This study looks at student understanding of key nature of science (NOS) concepts in order to examine the impact of implementing activities intended to help students better understand the process of science and to see if discussion of key NOS concepts following those activities will result in greater gains in NOS understanding. One class received an "activities only" treatment, while the other participated in the same activities followed by explicit discussion of key NOS themes relating to the activity. The interventions were implemented for one school year in two high school anatomy and physiology courses composed of juniors and seniors. Student views of the nature of science were measured using the Views of the Nature of Science - Form C (VNOS-C). Students in both classes demonstrated significant gains in NOS understanding. However, contrary to current research, the addition of explicit discussion did not result in significantly greater gains in NOS understanding. This suggests that perhaps students in higher-level science classes can draw the correlations between NOS related activities and important aspects of "real" science. Or perhaps that a curriculum with a varied approach my expose students to more aspects of science thus improving their NOS understanding.
ContributorsTalbot, Amanda L (Author) / Luft, Julie (Thesis advisor) / Baker, Dale (Committee member) / Brem, Sarah (Committee member) / Arizona State University (Publisher)
Created2010