arXiv subjects

Chandralekha Singh

Publications and source records attributed to Chandralekha Singh.

At least 55 records · Page 3Linked to original sources

arXiv2024

Role of inclusiveness of learning environment in predicting students' outcomes in courses in which women are not underrepresented

Student beliefs in introductory physics courses can influence their course outcomes and retention in STEM disciplines and future career aspirations. This study used survey data from 501 students in the first of two-semester algebra-based introductory physics courses primarily taken by bioscience majors, in which women make up approximately 65% of the class. We investigated how the learning environment including perceived recognition, peer interaction, and sense of belonging correlate with students' physics outcomes, including their physics self-efficacy, interest, and identity. We found that in general, women had lower physics beliefs than men and the learning environment plays a major role in explaining student outcomes. We also found that perceived recognition played an important role in predicting students' physics identity and students' sense of belonging played an important role in predicting students' physics self-efficacy in the first algebra-based introductory physics course investigated. These findings can be useful to contemplate strategies to create an equitable and inclusive learning environment to help all students to excel in these physics courses.

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arXiv2024

Challenges in addressing student difficulties with basics and change of basis for two-state quantum systems using a multiple-choice question sequence in online and in-person classes

Research-validated multiple-choice questions comprise an easy-to-implement instructional tool for scaffolding student learning and providing formative assessment of students' knowledge. We present findings from the implementation of a research-validated multiple-choice question sequence on the basics of two-state quantum systems, including inner products, outer products, translation between Dirac notation and matrix representation in a particular basis, and change of basis. This study was conducted in an advanced undergraduate quantum mechanics course, in both online and in-person learning environments, across three years. For each cohort, students had their learning assessed after traditional lecture-based instruction in relevant concepts before engaging with the multiple-choice question sequence. Their performance was evaluated again afterwards with a similar assessment and compared to their earlier performance. We analyze, compare, and discuss the trends observed in the three implementations.

physics.ed-ph↗

arXiv2024

Investigating and improving student understanding of the basics of quantum computing

Quantum information science and engineering (QISE) is a rapidly developing field that leverages the skills of experts from many disciplines to utilize the potential of quantum systems in a variety of applications. It requires talent from a wide variety of traditional fields, including physics, engineering, chemistry, and computer science, to name a few. To prepare students for such opportunities, it is important to give them a strong foundation in the basics of QISE, in which quantum computing plays a central role. In this study, we discuss the development, validation, and evaluation of a QuILT, or Quantum Interactive Learning Tutorial, on the basics and applications of quantum computing. These include an overview of key quantum mechanical concepts relevant for quantum computation (including ways a quantum computer is different from a classical computer), properties of single- and multi-qubit systems, and the basics of single-qubit quantum gates. The tutorial uses guided inquiry-based teaching-learning sequences. Its development and validation involved conducting cognitive task analysis from both expert and student perspectives and using common student difficulties as a guide. The inquiry-based learning sequences in the tutorial provide scaffolding support to help students develop a functional understanding. The final version of the validated tutorial was implemented in two distinct courses offered by the physics department with slightly different student populations and broader course goals. Students' understanding was evaluated after traditional lecture-based instruction on the requisite concepts, and again after engaging with the tutorial. We analyze and discuss their improvement in performance on concepts covered in the tutorial.

physics.ed-ph↗

arXiv2024

Investigating introductory and advanced students' difficulties with entropy and the second law of thermodynamics using a validated instrument

We use the Survey of Thermodynamic Processes and First and Second Laws-Long (STPFaSL-Long), a research-based survey instrument with 78 items at the level of introductory physics, to investigate introductory and advanced students' difficulties with entropy and the second law of thermodynamics. We present analysis of data from 12 different introductory and advanced physics classes at four different higher education public institutions in the US in which the survey was administered in-person to more than 1000 students. We find that a widespread unproductive tendency for introductory students to associate the properties of entropy with those of energy leads to many errors based on an idea of "conservation of entropy," in which entropy increases are always balanced by equal entropy decreases. For many of the more advanced students (calculus-based and upper level), we detect a tendency to expect entropy increases even in processes in which the entropy does not change. We observed a widespread failure to correctly apply the relationship ΔS = δQreversible/T, either by using it for irreversible processes to which it does not apply, or by applying it incorrectly or completely neglecting it in reversible processes to which it does apply. We also noted that many introductory students are simply not aware that total entropy must increase in any "spontaneous" heat transfer process. Students at all levels were very frequently found to be confused that while net entropy (system + reservoir) in reversible isothermal processes does not change, the entropy of the working substance itself does indeed increase or decrease depending on whether the process is an expansion or compression. Our findings are broadly consistent with prior research findings in this area, expanding upon them and revealing previously unreported aspects of students' thinking.

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arXiv2024

Development and validation of a conceptual multiple-choice survey instrument to assess student understanding of introductory thermodynamics

We discuss the development and validation of the long version of a conceptual multiple-choice survey instrument called the Survey of Thermodynamic Processes and First and Second Laws-Long (STPFaSL-Long) suitable for introductory physics courses. This version of the survey instrument is a longer version of the original shorter version developed and validated earlier. The 19 contexts including the exact wording of all of the problem situations posed in the two versions of the survey instrument are identical and the difference between the long and short versions of the instrument is only in the multiple-choice options. In particular, in the longer version of the survey instrument, there are no alternative conceptions explicitly embedded in the four multiple-choice options students choose from and the questions asked in a given context in one item of the shorter survey instrument were split into several items focusing, e.g., on different thermodynamic variables. After the development and validation of the longer version of the survey instrument, the final version was administered in 12 different in-person classes (four different institutions) in which students answered the questions in-class on paper scantron forms with the instructor as the proctor and 12 different in-person classes (five different institutions) in which students answered the questions online on Qualtrics within a two-hour period. This longer version of the survey instrument was administered to introductory physics students in various traditionally taught calculus-based and algebra-based classes before and after traditional lecture-based instruction in relevant concepts. It was also administered to upper-level undergraduates majoring in physics and Ph.D. students taught traditionally for bench marking purposes.

physics.ed-ph↗

arXiv2024

Investigating introductory and advanced students' difficulties with change in internal energy, work and heat transfer using a validated instrument

We use the Survey of Thermodynamic Processes and First and Second Laws-Long (STPFaSL-Long), a research-based survey instrument with 78 items at the level of introductory physics, to investigate introductory and advanced students' difficulties with internal energy, work, and heat transfer. We present analysis of data from 12 different introductory and advanced physics classes at four different higher education public institutions in the US in which the survey was administered in person to more than 1000 students. We find that not only introductory but also advanced physics students have many common difficulties with these introductory thermodynamic concepts after traditional lecture-based instruction in relevant concepts. We utilize a wide variety of problem types and contexts and our sample includes large numbers of introductory algebra-based, calculus-based, and advanced students. Some of our findings are consistent with prior research in this area, but others expand upon them and reveal previously unreported aspects of students' thinking. Findings related to common difficulties of students before and after traditional lecture-based instruction in college physics courses can help instructors of these courses plan instruction and curricula to improve student understanding. These findings can also be valuable for developing effective research-based curricula and pedagogies to address student difficulties and help students develop a functional understanding of these fundamental thermodynamic concepts.

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arXiv2024

How the physics culture shapes the experiences of undergraduate women physics majors: A comparative case study of three physics departments

We present comparative case study of three physics department culture from different institutions using the experiences undergraduate women. The three studies conducted in the United States include Johnson's 2020 study in a small physics department at a small predominantly White liberal arts college, Santana and Singh's 2023 study at a large predominantly White research institution, and Santana and Singh's 2024 study in a medium-sized physics department at a small predominantly White private liberal arts college. Using synergistic frameworks such as Standpoint Theory, Domains of Power, and the Holistic Ecosystem for Learning Physics in an Inclusive and Equitable Environment and reflections from undergraduate women, we aim to understand how those in the position of power, e.g., instructors, have important roles in establishing and maintaining safe, equitable, and inclusive environments for undergraduate students. Their accounts help us contrast the experiences of undergraduate women in physics departments with very different cultures. This comparative analysis is especially important for reflecting upon what can be done to improve the physics culture so that historically marginalized students such as women and ethnic and racial minority students in physics feel supported and thrive. In particular, this comparative case study can be invaluable to understand the positive and negative aspects of the physics culture as they impact undergraduate women majoring in physics within these three departments. This analysis can help other physics departments contemplate strategies to improve the physics culture so that all undergraduate physics majors have validating experiences while navigating their physics journey regardless of their identities.

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arXiv2024

Importance of accounting for student identities and intersectionality for creating equitable and inclusive physics learning environments

This research focuses on the experiences of seven undergraduate women who were majoring in physics in a medium-size physics department at a small liberal arts college. In the semi-structured, empathetic interviews we conducted, the women discussed how they decided to major in physics, their interactions with their peers and instructors, who supported them during their physics trajectory, and suggestions that would improve their experiences in physics. We used Standpoint theory and focused on the experiences of undergraduate women to get a holistic perspective of how they became interested in physics, how they have been supported in their physics journey as well as identify any challenges that they faced in their undergraduate physics program due to their identity. Using synergistic frameworks such as the Domains of Power and the Holistic Ecosystem for Learning Physics in an Inclusive and Equitable Environment (HELPIEE), we analyzed how those in the position of power, e.g., instructors, can play important roles in establishing and maintaining safe, equitable, and inclusive environments for students, which is especially important for historically marginalized students such as women and ethnic and racial minority students in physics. We also discuss the suggestions provided by the undergraduate women to implement in the future to support current and future undergraduate women in physics and astronomy. Their suggestions are separated as personal advice for peers and suggestions for physics instructors.

physics.ed-ph↗

arXiv2024

Challenges in addressing student difficulties with quantum measurement of two-state quantum systems using a multiple-choice question sequence in online and in-person classes

Research-validated multiple-choice questions comprise an easy-to-implement instructional tool that serves to scaffold student learning and formatively assess students' knowledge. We present findings from the implementation, in consecutive years, of a research-validated multiple-choice question sequence [referred to in this study as a Clicker Question Sequence (CQS)] on quantum measurement as it applies to two-state quantum systems. This study was conducted in an advanced undergraduate quantum mechanics course, in both online and in-person learning environments across three years. Student learning was assessed after traditional lecture-based instruction in relevant concepts, and their performance was compared with that on a similar assessment given after engaging with the CQS. We analyze, compare, and discuss the trends observed in the three implementations.

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arXiv2024

Statistically equivalent models with different causal structures: An example from physics identity

Structural equation modeling (SEM) is a statistical method widely used in educational research to investigate relationships between variables. SEM models are typically constructed based on theoretical foundations and assessed through fit indices. However, a well-fitting SEM model alone is not sufficient to verify the causal inferences underlying the proposed model, as there are statistically equivalent models with distinct causal structures that equally well fit the data. Therefore, it is crucial for researchers using SEM to consider statistically equivalent models and to clarify why the proposed model is more accurate than the equivalent ones. However, many SEM studies did not explicitly address this important step, and no prior study in physics education research has delved into potential methods for distinguishing statistically equivalent models with differing causal structures. In this study, we use physics identity model as an example to discuss the importance of considering statistically equivalent models and how other data can help to distinguish them. Previous research has identified three dimensions of physics identity: perceived recognition, self-efficacy, and interest. However, the relationships between these dimensions have not been thoroughly understood. In this paper, we specify a model with perceived recognition predicting self-efficacy and interest, which is inspired by individual interviews with students in physics courses to make physics learning environments equitable and inclusive. We test our model with fit indices and discuss its statistically equivalent models with different causal inferences among perceived recognition, self-efficacy, and interest. We then discuss potential experiments that could further empirically test the causal inferences underlying the models, aiding the refinement to a more accurate causal model for guiding educational improvements.

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arXiv2024

Gender Equity in Physics Labs: A Review

This review article provides an overview of research on the topic of gender equity in educational physics labs. As many institutions and instructors seek to evolve or transform physics lab learning, it is important that changes are made that improve equity for all students along multiple axes of identity, including gender. The studies highlighted in this review article describe the existence of complex gender-based differences, e.g., in opportunities to tinker with lab equipment, as well as differences in grades, conceptual understanding, and motivational outcomes across a broad range of lab curricula and contexts. The studies also illustrate and explore social interactions and structures that can impact students' experiences based on their gender identities. Although there has been less scholarship focused on proposals to reduce gender-based inequities in labs, this review article also provides an overview of some relevant proposals as well as associated research results. This overview of research on gender equity in physics labs helps to make clear that future scholarship on equity in physics labs should adopt gender frameworks that allow researchers to transcend binary gender identities and student deficit framing of research results. Likewise, a case is made that future research is needed on equity along other axes of identity, as well as research that accounts for intersectionality of different identities, in the physics lab context.

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arXiv2024

Lessons from Transforming Second-Year Honors Physics Lab

New technology like the Arduino microcontroller platform presents an opportunity to transform Beyond the First Year (BFY) physics labs to better prepare physics students for work in research labs and beyond. The flexibility, low cost, and power of these devices provides an attractive way for students to learn to use and master research-grade instrumentation. Therefore, we introduced new technology, including Arduino Due microcontroller boards, to a second-year honors physics lab in order to provide improved learning experiences for students. This transformation was implemented in three lab modules and focused on diminishing the black box nature of the traditional labs while encouraging students to engage in troubleshooting. The importance of troubleshooting was made evident to students by the instructor emphasizing it as an inevitable and central part of experimentation. This lab transformation also required that students perform work that was `above and beyond' the scope of the assigned experimental work for part of the course credit. While the technological aspects of the transformation were received well by a majority of students, our observations during the initial implementation suggested a need for some modifications to instructional practices in order to improve the learning and experiences for all students. In particular, we find that many students can benefit from additional scaffolding in order to complete `above and beyond' work. Similarly, we find that students in general, and underrepresented students such as women in particular, may need thoughtful intervention from the instructor, e.g., in order to avoid becoming isolated when the lab work is designed for pair work. Otherwise, some students may be left to work alone with a disproportionate work-load if students choose their own partners.

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arXiv2024

Student Understanding of the Bloch Sphere

Quantum information science is a rapidly growing interdisciplinary field that is attracting the attention of academics and industry experts alike. It requires talent from a wide variety of traditional fields, including physics, engineering, chemistry, and computer science, to name a few. To prepare students for such opportunities, it is important to give them a strong foundation in the basics of quantum information science, in which quantum computing plays a central role. In this study, we discuss the development, validation, and evaluation of a tutorial on the Bloch sphere, a useful visual tool for developing intuition about single quantum bits (qubits), which are the basic building block of any quantum computer. Students' understanding was evaluated after they received traditional lecture-based instruction on the requisite topics, and again after engaging with the tutorial. We observe, analyze, and discuss their improvement in performance on concepts covered in the tutorial.

physics.ed-ph↗

arXiv2024

Challenges in addressing student difficulties with time-development of two-state quantum systems using a multiple-choice question sequence in virtual and in-person classes

Research-validated clicker questions as instructional tools for formative assessment are relatively easy to implement and can provide effective scaffolding when developed and implemented in a sequence. We present findings from the implementation of a research-validated clicker question sequence (CQS) on student understanding of the time-development of two-state quantum systems. This study was conducted in an advanced undergraduate quantum mechanics course for two consecutive years in virtual and in-person classes. The effectiveness of the CQS discussed here in both modes of instruction was determined by evaluating students' performance after traditional lecture-based instruction and comparing it to their performance after engaging with the CQS.

physics.ed-ph↗

arXiv2024

Challenges in addressing student difficulties with measurement uncertainty of two-state quantum systems using a multiple-choice question sequence in online and in-person classes

Research-validated multiple-choice questions comprise an easy-to-implement instructional tool that serves to scaffold student learning and formatively assess students knowledge. We present findings from the implementation, in consecutive years, of research-validated multiple-choice question sequence on measurement uncertainty as it applies to two-state quantum systems. This study was conducted in an advanced undergraduate quantum mechanics course, in an online and in-person learning environments in consecutive years. Student learning was assessed after receiving traditional lecture-based instruction in relevant concepts, and their performance was compared with that on a similar assessment given after engaging with the multiple-choice question sequence. We analyze and discuss the similar and differing trends observed in the two modes of instruction.

physics.ed-ph↗

arXiv2023

Peer interaction facilitates co-construction of knowledge in quantum mechanics

Collaborative learning with peers can lead to students learning from each other and solving physics problems correctly not only in situations in which one student knows how to solve the problems but also when none of the students can solve the problems alone. We define the rate of construction as the percentage of groups collaborating on problem-solving that solve the problem correctly out of all groups having at least one member who answered correctly and one incorrectly while solving the same problem individually first. We define the rate of co-construction on each problem as the percentage of collaborating groups that answered it correctly if no student in the group individually answered it correctly before the collaborative work. In this study, we investigated student learning measured by student performance on a validated quantum mechanics survey and rates of construction and co-construction of knowledge when students first worked individually after lecture-based instruction in relevant concepts and then worked with peers during class without receiving any feedback from the course instructor. We find that construction of knowledge consistently occurred at a high rate during peer collaboration. However, rates of co-construction were more varied. High rates of co-construction were generally achieved when approximately half of the students knew the correct answers initially. We also conducted an analysis of some of the survey questions that correlate with high rates of co-construction to gain some insight into what students converged on after peer interaction and what types of difficulties were reduced. Our findings can be valuable for instructors who want to provide in-class and out-of-class opportunities for peer collaboration in their physics courses.

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arXiv2023

Using the Conceptual Survey of Electricity and Magnetism to investigate progression in student understanding from introductory to advanced levels

The Conceptual Survey of Electricity and Magnetism (CSEM) is a multiple-choice survey that contains a variety of electricity and magnetism concepts from Coulomb's law to Faraday's law at the level of introductory physics used to help inform instructors of student mastery of those concepts. Prior studies suggest that many concepts on the survey are challenging for introductory physics students and the average student scores after traditional instruction are low. The research presented here investigates the progression in student understanding on the CSEM. We compare the performance of students in introductory and advanced level physics courses to understand the evolution of student understanding of concepts covered in the CSEM after traditional lecture-based instruction. We find that on all CSEM questions on which less than 50% of the introductory physics students answered a question correctly after instruction, less than two thirds of the upper-level undergraduate students provided the correct response after traditional instruction. We also analyzed the CSEM data from graduate students for benchmarking purposes. We discuss the CSEM questions that remain challenging and the common alternative conceptions among upper-level students. The findings presented here at least partly point to the fact that traditional instruction in upper-level courses which typically focuses primarily on quantitative problem solving and incentivizes use of algorithmic approaches is not effective for helping students develop a solid understanding of these concepts. However, it is important for helping students integrate conceptual and quantitative aspects of learning in order to build a robust knowledge structure of basic concepts in electricity and magnetism.

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arXiv2023

Using the Energy and Momentum Conceptual Survey to investigate progression in student understanding from introductory to advanced levels

The Energy and Momentum Conceptual Survey (EMCS) is a multiple-choice survey that contains conceptual problems involving a variety of energy and momentum concepts covered in a typical introductory physics course for science and engineering majors. Prior studies suggest that many concepts on the survey are challenging for introductory physics students and the average student scores after traditional lecture-based instruction are low. The research presented here investigates the progression in student understanding of the EMCS concepts including their evolution from the beginning to the end of their courses in introductory and advanced level undergraduate physics after traditional lecture-based instruction. We find that on all EMCS questions on which less than 50% of the introductory physics students answered a question correctly after traditional instruction, less than two-thirds of the upper-level undergraduate students provided the correct response after traditional lecture-based instruction. We discuss the EMCS questions that remain challenging and the common alternate conceptions among upper-level students. The findings presented here are consistent with prior research showing that traditional instruction in upper-level courses, which typically focuses primarily on quantitative problem solving and often incentivizes use of algorithmic approaches, is not effective for helping many students develop a functional understanding of underlying concepts.

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