arXiv subjects

Chandralekha Singh

Publications and source records attributed to Chandralekha Singh.

At least 181 records · Page 10Linked to original sources

arXiv2016

Using Analogy to Solve a Three-Step Physics Problem

In a companion paper, we discuss students' ability to take advantage of what they learn from a solved problem and transfer their learning to solve a quiz problem that has different surface features but the same underlying physics principles. Here, we discuss students' ability to perform analogical reasoning between another pair of problems. Both the problems can be solved using the same physics principles. However, the solved problem provided was a two- step problem (which can be solved by decomposing it into two sub-problems) while the quiz problem was a three-step problem. We find that it is challenging for students to extend what they learned from a two-step problem to solve a three-step problem.

physics.ed-ph↗

arXiv2016

Using Reflection with Peers to Help Students Learn Effective Problem Solving Strategies

We describe a study in which introductory physics students engage in reflection with peers about problem solving. The recitations for an introductory physics course with 200 students were broken into the "Peer Reflection" (PR) group and the traditional group. Each week in recitation, students in the PR group reflected in small teams on selected problems from the homework. The graduate and undergraduate teaching assistants (TAs) in the PR group recitations provided guidance and coaching to help students learn effective problem solving heuristics. In the recitations for the traditional group, students had the opportunity to ask the graduate TA questions about the homework before they took a weekly quiz. On the final exam with only multiple-choice questions, the PR group drew diagrams on more problems than the traditional group, even when there was no external reward for doing so. Since there was no partial credit for drawing the diagrams on the scratch books, students did not draw diagrams simply to get credit for the effort shown and must value the use of diagrams for solving problems if they drew them. We also find that, regardless of whether the students belonged to the traditional or PR groups, those who drew more diagrams for the multiple-choice questions outperformed those who did not draw them.

physics.ed-ph↗

arXiv2016

Can multiple-choice questions simulate free-response questions?

We discuss a study to evaluate the extent to which free-response questions could be approximated by multiple-choice equivalents. Two carefully designed research-based multiple-choice questions were transformed into a free-response format and administered on the final exam in a calculus-based introductory physics course. The original multiple-choice questions were administered in another similar introductory physics course on final exam. Findings suggest that carefully designed multiple-choice questions can reflect the relative performance of the free-response questions while maintaining the benefits of ease of grading and quantitative analysis, especially if the different choices in the multiple-choice questions are weighted to reflect the different levels of understanding that students display.

physics.ed-ph↗

arXiv2016

The group administered interactive questionnaire: An alternative to individual interviews

Individual interviews are often considered to be the gold standard for researchers to understand how people think about phenomena. However, conducting and analyzing interviews is very time consuming. This paper presents the Group Administered Interactive Questionnaire (GAIQ) as an alternative to individual interviews and discusses the pros and cons of each data collection method. Use of GAIQ will be discussed in the context of a study that seeks to understand teaching assistants' reasons for the design of problem solutions for introductory physics.

physics.ed-ph↗

arXiv2016

Using Analogical Problem Solving with Different Scaffolding Supports to Learn about Friction

Prior research suggests that many students believe that the magnitude of the static frictional force is always equal to its maximum value. Here, we examine introductory students' ability to learn from analogical reasoning (with different scaffolding supports provided) between two problems that are similar in terms of the physics principle involved but one problem involves static friction, which often triggers the misleading notion. To help students process through the analogy deeply and contemplate whether the static frictional force was at its maximum value, students in different recitation classrooms received different scaffolding support. We discuss students' performance in different groups.

physics.ed-ph↗

arXiv2016

TA-designed vs. research-oriented problem solutions

In order to study graduate teaching assistants (TAs) beliefs and values about the design of instructor problem solutions, twenty-four TAs were provided with different solutions and asked to discuss their preferences for prominent solution features. TAs preferences for solution features were examined in light of the modeling of expert-like problem solving process as recommended in the literature. Results suggest that while many of the features TAs valued align with expert-like problem solving approaches, they noticed primarily "surface features" of solutions. Moreover, self-reported preferences did not match well with the solutions TAs wrote on their own.

physics.ed-ph↗

arXiv2016

Centripetal Acceleration: Often Forgotten or Misinterpreted

Acceleration is a fundamental concept in physics which is taught in mechanics at all levels. Here, we discuss some challenges in teaching this concept effectively when the path along which the object is moving has a curvature and centripetal acceleration is present. We discuss examples illustrating that both physics teachers and students have difficulty with this concept. We conclude with instructional strategies that may help students with this challenging concept.

physics.ed-ph↗

arXiv2016

Categorization of Quantum Mechanics Problems by Professors and Students

We discuss the categorization of 20 quantum mechanics problems by physics professors and undergraduate students from two honors-level quantum mechanics courses. Professors and students were asked to categorize the problems based upon similarity of solution. We also had individual discussions with professors who categorized the problems. Faculty members' categorizations were overall rated higher than those of students by three faculty members who evaluated all of the categorizations. The categories created by faculty members were more diverse compared to the categories they created for a set of introductory mechanics problems. Some faculty members noted that the categorization of introductory physics problems often involves identifying fundamental principles relevant for the problem, whereas in upper-level undergraduate quantum mechanics problems, it mainly involves identifying concepts and procedures required to solve the problem. Moreover, physics faculty members who evaluated others' categorizations expressed that the task was very challenging and they sometimes found another person's categorization to be better than their own. They also rated some concrete categories such as "hydrogen atom" or "simple harmonic oscillator" higher than other concrete categories such as "infinite square well" or "free particle".

physics.ed-ph↗

arXiv2016

Assessing Student Expertise in Introductory Physics with Isomorphic Problems, Part II: Effect of Some Potential Factors on Problem Solving and Transfer

In this companion paper, we explore the use of isomorphic problem pairs (IPPs) to assess introductory physics students' ability to solve and successfully transfer problem-solving knowledge from one context to another in mechanics. We call the paired problems "isomorphic" because they require the same physics principle to solve them. We analyze written responses and individual discussions to a range of isomorphic problems. We examine potential factors that may help or hinder transfer of problem-solving skills from one problem in a pair to the other. For some paired isomorphic problems, one context often turned out to be easier for students in that it was more often correctly solved than the other. When quantitative and conceptual questions were paired and given back to back, students who answered both questions in the IPP often performed better on the conceptual questions than those who answered the corresponding conceptual questions only. Although students often took advantage of the quantitative counterpart to answer a conceptual question of an IPP correctly, when only given the conceptual question, students seldom tried to convert it into a quantitative question, solve it and then reason about the solution conceptually. Misconceptions associated with friction in some problems were so robust that pairing them with isomorphic problems not involving friction did not help students discern their underlying similarities. Alternatively, from the knowledge in pieces perspective, the activation of the knowledge resource related to friction was so strongly and automatically triggered by the context, which is outside the conscious control of the student, that students did not look for analogies with paired problems or other aids that may be present.

physics.ed-ph↗

arXiv2016

Improving Students' Understanding of Quantum Mechanics via the Stern-Gerlach Experiment

The Stern-Gerlach experiment has played a central role in the discovery of spin angular momentum. It can also play a pivotal role in teaching the formalism of quantum mechanics using a concrete example involving a finite-dimensional Hilbert space. Using this context, students can learn about how to prepare a specific quantum state starting from an arbitrary state, issues related to the time evolution of the wave function, and quantum measurement. It can also be exploited to teach students about the distinction between the physical space where one performs the experiment and the Hilbert space where the state of the system lies and how the information about the state of the system in the Hilbert space can be exploited to interpret the possible outcomes of the experiment in the physical space. Students can learn the advantages of choosing an appropriate basis to make suitable predictions about the outcomes of experiments with different arrangements of Stern-Gerlach devices. This experiment can also help students understand that an ensemble of identically prepared systems, e.g., one in a linear superposition of two stationary states, is not the same as a mixture, e.g., in which half of the systems are in one stationary state and the other half are in the other stationary state. Here, we discuss investigation of students' difficulties about the Stern-Gerlach experiment by giving written tests and interviewing advanced undergraduate and graduate students in quantum mechanics courses. We also discuss preliminary data from two quantum mechanics courses that suggest that a Quantum Interactive Learning Tutorial (QuILT) related to the Stern-Gerlach experiment is helpful in improving students' understanding of these concepts.

physics.ed-ph↗

arXiv2016

Challenges in Analogical Reasoning

Learning physics requires understanding the applicability of fundamental principles in a variety of contexts that share deep features. One way to help students learn physics is via analogical reasoning. Students can be taught to make an analogy between situations that are more familiar or easier to understand and another situation where the same physics principle is involved but that is more difficult to handle. Here, we examine introductory physics students' ability to use analogies in solving problems involving Newton's second law. Students enrolled in an algebra-based introductory physics course were given a solved problem involving tension in a rope and were then asked to solve another problem for which the physics is very similar but involved a frictional force. They were asked to point out the similarities between the two problems and then use the analogy to solve the friction problem.

physics.ed-ph↗

arXiv2016

Can Free-Response Questions Be Approximated by Multiple-Choice Equivalents?

We discuss a study to evaluate the extent to which free-response questions can be approximated by multiple-choice equivalents. Two carefully designed research-based multiple-choice questions were transformed into a free-response format and administered on the final exam in a calculus-based introductory physics course. The original multiple-choice questions were administered in another, similar introductory physics course on the final exam. Our findings suggest that carefully designed multiple-choice questions can reflect the relative performance on the free-response questions while maintaining the benefits of ease of grading and quantitative analysis, especially if the different choices in the multiple-choice questions are weighted to reflect the different levels of understanding that students display.

physics.ed-ph↗

arXiv2016

What Can Learn from PER: Physics Education Research?

I believe that most teachers develop a belief in a set of pedagogical practices. As we teach, we try different ways to teach topics and then judge how successful the methods were. After several years, we have a compilation of techniques in our teaching toolbox. New teachers are at a disadvantage because they have fewer prior experiences to draw upon. Luckily, there is a group of physicists and physics educators who are researching how students learn physics, and have been able to show evidence of effective education practices in physics. They field of study is called PER: Physics Education Research. I asked Chandralekha Singh, one of the leaders in PER, to summarize some of the most relevant PER findings and her response follows.

physics.ed-ph↗

arXiv2016

Surveying Students' Understanding of Quantum Mechanics

Development of conceptual multiple-choice tests related to a particular physics topic is important for designing research-based learning tools to reduce the difficulties. We explore the difficulties that the advanced undergraduate and graduate students have with non-relativistic quantum mechanics of one particle in one spatial dimension. We developed a research-based conceptual multiple-choice survey that targets these issues to obtain information about the common difficulties and administered it to more than a hundred students from seven different institutions. The issues targeted in the survey include the set of possible wavefunctions, bound and scattering states, quantum measurement, expectation values, the role of the Hamiltonian, time-dependence of wavefunction and time-dependence of expectation value. We find that the advanced undergraduate and graduate students have many common difficulties with these concepts and that research-based tutorials and peer-instruction tools can significantly reduce these difficulties. The survey can be administered to assess the effectiveness of various intructional strategies.

physics.ed-ph↗

arXiv2016

Interactive tutorial to improve student understanding of single photon experiments involving a Mach-Zehnder Interferometer

We have developed and evaluated a Quantum Interactive Learning Tutorial (QuILT) on a Mach-Zehnder Interferometer with single photons to expose upper-level students in quantum mechanics courses to contemporary quantum optics applications. The QuILT strives to help students develop the ability to apply fundamental quantum principles to physical situations in quantum optics and explore the differences between classical and quantum ideas. The QuILT adapts visualization tools to help students build physical intuition about counter-intuitive quantum optics phenomena with single photons including a quantum eraser setup and focuses on helping them integrate qualitative and quantitative understanding. We discuss findings from in-class evaluations.

physics.ed-ph↗

arXiv2016

Transfer of Learning in Quantum Mechanics

We investigate the difficulties that undergraduate students in quantum mechanics courses have in transferring learning from previous courses or within the same course from one context to another by administering written tests and conducting individual interviews. Quantum mechanics is abstract and its paradigm is very different from the classical one. A good grasp of the principles of quantum mechanics requires creating and organizing a knowledge structure consistent with the quantum postulates. Previously learned concepts such as the principle of superposition and probability can be useful in quantum mechanics if students are given opportunity to build associations between new and prior knowledge. We also discuss the need for better alignment between quantum mechanics and modern physics courses taken previously because semi-classical models can impede internalization of the quantum paradigm in more advanced courses.

physics.ed-ph↗

arXiv2016

Assessing and improving student understanding of quantum mechanics

We developed a survey to probe student understanding of quantum mechanics concepts at the beginning of graduate instruction. The survey was administered to 202 graduate students in physics enrolled in first-year quantum mechanics courses from seven different universities at the beginning of the first semester. We also conducted one-on-one interviews with fifteen graduate students or advanced undergraduate students who had just finished a course in which all the content on the survey was covered. We find that students share universal difficulties about fundamental quantum mechanics concepts. The difficulties are often due to over-generalization of concepts learned in one context to other contexts where they are not directly applicable and difficulty in making sense of the abstract quantitative formalism of quantum mechanics. Instructional strategies that focus on improving student understanding of these concepts should take into account these difficulties. The results from this study can sensitize instructors of first-year graduate quantum physics to the conceptual difficulties students are likely to face.

physics.ed-ph↗

arXiv2016

Improving Students' Understanding of Quantum Measurement

We describe the difficulties advanced undergraduate and graduate students have with quantum measurement. To reduce these difficulties, we have developed research-based learning tools such as the Quantum Interactive Learning Tutorial (QuILT) and peer instruction tools. A preliminary evaluation shows that these learning tools are effective in improving students' understanding of concepts related to quantum measurement.

physics.ed-ph↗