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This dissertation is presented in two sections. First, I explore two methods of using stable isotope analysis to trace environmental and biogeochemical processes. Second, I present two related studies investigating student understanding of the biogeochemical concepts that underlie part one. Fe and Hg are each biogeochemically important elements in their

This dissertation is presented in two sections. First, I explore two methods of using stable isotope analysis to trace environmental and biogeochemical processes. Second, I present two related studies investigating student understanding of the biogeochemical concepts that underlie part one. Fe and Hg are each biogeochemically important elements in their own way. Fe is a critical nutrient for phytoplankton, while Hg is detrimental to nearly all forms of life. Fe is often a limiting factor in marine phytoplankton growth. The largest source, by mass, of Fe to the open ocean is windblown mineral dust, but other more soluble sources are more bioavailable. To look for evidence of these non-soil dust sources of Fe to the open ocean, I measured the isotopic composition of aerosol samples collected on Bermuda. I found clear evidence in the fine size fraction of a non-soil dust Fe source, which I conclude is most likely from biomass burning. Widespread adoption of compact fluorescent lamps (CFL) has increased their importance as a source of environmental Hg. Isotope analysis would be a useful tool in quantifying this impact if the isotopic composition of Hg from CFL were known. My measurements show that CFL-Hg is isotopically fractionated, in a unique pattern, during normal operation. This fractionation is large and has a distinctive, mass-independent signature, such that CFL Hg can be uniquely identified from other sources. Misconceptions research in geology has been a very active area of research, but student thinking regarding the related field of biogeochemistry has not yet been studied in detail. From interviews with 40 undergraduates, I identified over 150 specific misconceptions. I also designed a multiple-choice survey (concept inventory) to measure understanding of these same biogeochemistry concepts. I present statistical evidence, based on the Rasch model, for the reliability and validity of this instrument. This instrument will allow teachers and researchers to easily quantify learning outcomes in biogeochemistry and will complement existing concept inventories in geology, chemistry, and biology.
ContributorsMead, Chris (Author) / Anbar, Ariel (Thesis advisor) / Semken, Steven (Committee member) / Shock, Everett (Committee member) / Herckes, Pierre (Committee member) / Hartnett, Hilairy (Committee member) / Arizona State University (Publisher)
Created2014
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This research study investigated the effects of high fidelity graphics on both learning and presence, or the "sense of being there," inside a Virtual Learning Environment (VLE). Four versions of a VLE on the subject of the element mercury were created, each with a different combination of high and

This research study investigated the effects of high fidelity graphics on both learning and presence, or the "sense of being there," inside a Virtual Learning Environment (VLE). Four versions of a VLE on the subject of the element mercury were created, each with a different combination of high and low fidelity polygon models and high and low fidelity shaders. A total of 76 college age (18+ years of age) participants were randomly assigned to one of the four conditions. The participants interacted with the VLE and then completed several posttest measures on learning, presence, and attitudes towards the VLE experience. Demographic information was also collected, including age, computer gameplay experience, number of virtual environments interacted with, gender and time spent in this virtual environment. The data was analyzed as a 2 x 2 between subjects ANOVA.

The main effects of shader fidelity and polygon fidelity were both non- significant for both learning and all presence subscales inside the VLE. In addition, there was no significant interaction between shader fidelity and model fidelity. However, there were two significant results on the supplementary variables. First, gender was found to have a significant main effect on all the presence subscales. Females reported higher average levels of presence than their male counterparts. Second, gameplay hours, or the number of hours a participant played computer games per week, also had a significant main effect on participant score on the learning measure. The participants who reported playing 15+ hours of computer games per week, the highest amount of time in the variable, had the highest score as a group on the mercury learning measure while those participants that played 1-5 hours per week had the lowest scores.
ContributorsHorton, Scott (Author) / Nelson, Brian (Thesis advisor) / Savenye, Wilhelmina (Committee member) / Atkinson, Robert (Committee member) / Arizona State University (Publisher)
Created2014
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Description
Affect is a domain of psychology that includes attitudes, emotions, interests, and values. My own affect influenced the choice of topics for my dissertation. After examining asteroid interiors and the Moon’s thermal evolution, I discuss the role of affect in online science education. I begin with asteroids, which are collections

Affect is a domain of psychology that includes attitudes, emotions, interests, and values. My own affect influenced the choice of topics for my dissertation. After examining asteroid interiors and the Moon’s thermal evolution, I discuss the role of affect in online science education. I begin with asteroids, which are collections of smaller objects held together by gravity and possibly cohesion. These “rubble-pile” objects may experience the Brazil Nut Effect (BNE). When a collection of particles of similar densities, but of different sizes, is shaken, smaller particles will move parallel to the local gravity vector while larger objects will do the opposite. Thus, when asteroids are shaken by impacts, they may experience the BNE as possibly evidenced by large boulders seen on their surfaces. I found while the BNE is plausible on asteroids, it is confined to only the outer layers. The Moon, which formed with a Lunar Magma Ocean (LMO), is the next topic of this work. The LMO is due to the Moon forming rapidly after a giant impact between the proto-Earth and another planetary body. The first 80% of the LMO solidified rapidly at which point a floatation crust formed and slowed solidification of the remaining LMO. Impact bombardment during this cooling process, while an important component, has not been studied in detail. Impacts considered here are from debris generated during the formation of the Moon. I developed a thermal model that incorporates impacts and find that impacts may have either expedited or delayed LMO solidification. Finally, I return to affect to consider the differences in attitudes towards science between students enrolled in fully-online degree programs and those enrolled in traditional, in-person degree programs. I analyzed pre- and post-course survey data from the online astrobiology course Habitable Worlds. Unlike their traditional program counterparts, students enrolled in online programs started the course with better attitudes towards science and also further changed towards more positive attitudes during the course. Along with important conclusions in three research fields, this work aims to demonstrate the importance of affect in both scientific research and science education.
ContributorsDingatantrige Perera, Jude Viranga (Author) / Asphaug, Erik (Thesis advisor) / Semken, Steven (Thesis advisor) / Anbar, Ariel (Committee member) / Elkins-Tanton, Linda T. (Committee member) / Robinson, Mark (Committee member) / Arizona State University (Publisher)
Created2017
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Description
Museum evaluation is an important process that aims to study an exhibit's effectiveness in engaging visitors and in teaching concepts. Imperatives and methods to strengthen museum evaluation have been suggested and implemented in the past, but ultimately faced several challenges including the collection of visitor feedback in an efficient, non-intrusive

Museum evaluation is an important process that aims to study an exhibit's effectiveness in engaging visitors and in teaching concepts. Imperatives and methods to strengthen museum evaluation have been suggested and implemented in the past, but ultimately faced several challenges including the collection of visitor feedback in an efficient, non-intrusive way. The Ask Dr. Discovery project seeks to address the challenge of conducting efficient, affordable, and large-scale science museum evaluation via an interactive app aimed at collecting direct visitor feedback through use of the app and through questionnaires that also collect demographics. This thesis investigates how the demographics of metro Phoenix science museum visitors as a whole compare to the Hispanic/Latino population of visitors, and makes use of visitor feedback from Ask Dr. Discovery to provide useful data for science museum evaluation. An analysis of responses revealed that the majority of the participants in the study (n=785) were White (Non-Hispanic) (65.59%), were 36-45 years old (36.18%) and hold a graduate degree (27.64%). Most Hispanic/Latino participants in the study were 26-35 years old (36.36%) and completed some college (28.67%). Most participants from both participant groups have never visited the museum before (32.99% of all participants; 33.57% of all Hispanics/Latinos). Further analysis suggest that museum visits may be independent of age and visitor group size. Visitor interest in science museum exhibits may be independent of their use of free time science-related activities. Data suggests that there was no real difference in exhibit interest across two different versions of the app ("modes"). Analysis of negative visitor feedback showed different question types, questions asked, and time spent on the app. Data log questions revealed the difference in time spent on the app and complexity of questions asked between adults and children, as well as the location of participants in the museum. There was no major correlation between mode type and number of questions asked, and length of use and number of questions asked.
ContributorsFernandez, Ivan (Author) / Bowman, Judd (Thesis director) / Bowman, Catherine (Committee member) / Nelson, Brian (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
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Description
Paper assessment remains to be an essential formal assessment method in today's classes. However, it is difficult to track student learning behavior on physical papers. This thesis presents a new educational technology—Web Programming Grading Assistant (WPGA). WPGA not only serves as a grading system but also a feedback delivery tool

Paper assessment remains to be an essential formal assessment method in today's classes. However, it is difficult to track student learning behavior on physical papers. This thesis presents a new educational technology—Web Programming Grading Assistant (WPGA). WPGA not only serves as a grading system but also a feedback delivery tool that connects paper-based assessments to digital space. I designed a classroom study and collected data from ASU computer science classes. I tracked and modeled students' reviewing and reflecting behaviors based on the use of WPGA. I analyzed students' reviewing efforts, in terms of frequency, timing, and the associations with their academic performances. Results showed that students put extra emphasis in reviewing prior to the exams and the efforts demonstrated the desire to review formal assessments regardless of if they were graded for academic performance or for attendance. In addition, all students paid more attention on reviewing quizzes and exams toward the end of semester.
ContributorsHuang, Po-Kai (Author) / Hsiao, I-Han (Thesis advisor) / Nelson, Brian (Committee member) / VanLehn, Kurt (Committee member) / Arizona State University (Publisher)
Created2017
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Description
Ethnogeology is the scientific study of human relationships with the Earth as a system, typically conducted within the context of a specific culture. Indigenous or historically resident people may perceive local places differently from outside observers trained in the Western tradition. Ethnogeologic knowledge includes traditional indigenous knowledge (alternatively referred

Ethnogeology is the scientific study of human relationships with the Earth as a system, typically conducted within the context of a specific culture. Indigenous or historically resident people may perceive local places differently from outside observers trained in the Western tradition. Ethnogeologic knowledge includes traditional indigenous knowledge (alternatively referred to as traditional ecological knowledge or TEK), which exceeds the boundaries of non-Indigenous ideas of physical characteristics of the world, tends to be more holistic, and is culturally framed. In this ethnogeological study, I have implemented several methods of participatory rapid assessment (PRA) from the discipline of field ethnography to collect culturally framed geological knowledge, as well to measure the authenticity of the knowledge collected. I constructed a cultural consensus model (CCM) about karst as a domain of knowledge. The study area is located in the karst physiographic region of the Caribbean countries of the Dominican Republic (DR) and Puerto Rico (PR). Ethnogeological data collected and analyzed using CCM satisfied the requirements of a model where I have found statistically significance among participant’s agreement and competence values. Analysis of the competence means in the population of DR and PR results in p < 0.05 validating the methods adapted for this study. I discuss the CCM for the domain of karst (in its majority) that is shared among consultants in the countries of PR and the DR that is in the form of metaphors and other forms of culturally framed descriptions. This work continuing insufficient representation of minority groups such as Indigenous people, Native Americans, Alaska Natives, and Hispanic/Latinxs in the Earth Sciences.
ContributorsGarcia, Angel Antonio (Author) / Semken, Steven (Thesis advisor) / Brandt, Elizabeth, (Committee member) / Shock, Everett (Committee member) / Bowman, Catherine (Committee member) / Anbar, Ariel (Committee member) / Arizona State University (Publisher)
Created2018