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One of the most promising sources of gravitational waves for the forthcoming LISA observatory are ``extreme mass ratio inspirals&#39;&#39; (EMRIs) : compact objects like a stellar mass black hole falling into a massive black hole, typically with mass ratios of 1 to 1 million. These sources will be important probes of the astrophysical dynamics in the nuclear star clusters of galaxies, as well as provide detailed spacetime maps of the black hole (analogous to satellite geodesy around the earth). EMRIs are expected to have high eccentricities, and when the periapsis dips very near the black hole exhibit an orbit phenomenon known as ``zoom-whirl&#39;&#39; behavior, where rapid near-circular &quot;whirls&quot; are followed by a &quot;zoom&quot; out to apoapsis. These cause a complicated waveform that are useful for mapping out the gravitational structure of the system. Zoom-whirl behavior can be intuitively understood in the context of effective potentials, which should be familiar to students from classical orbital theory in mechanics. Here we demonstrate and explain zoom-whirl orbits using effective potential theory around Schwarzschild black holes, and demonstrate a public tool for visualizing EMRIs from this viewpoint, suitable for use in a variety of classroom settings.

AAPT SM 21

Understanding exotic gravitational wave orbits with effective potentials

effective potentials

lisa

gravitational waves

black holes

classical mechanics

astrophysics

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AAPT WM 21

One of the most promising sources of gravitational waves for the forthcoming LISA observatory are ``extreme mass ratio inspirals'' (EMRIs) : compact objects like a stellar mass black hole falling into a massive black hole, typically with mass ratios of 1 to 1 million. These sources will be important probes of the astrophysical dynamics in the nuclear star clusters of galaxies, as well as provide detailed spacetime maps of the black hole (analogous to satellite geodesy around the earth). EMRIs are expected to have high eccentricities, and when the periapsis dips very near the black hole exhibit an orbit phenomenon known as ``zoom-whirl'' behavior, where rapid near-circular "whirls" are followed by a "zoom" out to apoapsis. These cause a complicated waveform that are useful for mapping out the gravitational structure of the system. Zoom-whirl behavior can be intuitively understood in the context of effective potentials, which should be familiar to students from classical orbital theory in mechanics. Here we demonstrate and explain zoom-whirl orbits using effective potential theory around Schwarzschild black holes, and demonstrate a public tool for visualizing EMRIs from this viewpoint, suitable for use in a variety of classroom settings.

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Research-based assessments can provide instructors insights into the efficacy of their teaching and course transformations. As education shifts to focusing more on scientific practices and crosscutting concepts in addition to conceptual knowledge, there is a need for an assessment that can assess these 3-dimensions of learning and inform instructional approaches that foster this learning. In this talk, we present a first-look at an upper-division thermal physics assessment that explicitly targets scientific practices, crosscutting concepts, and conceptual knowledge using coupled, multiple-response items. We will present an example assessment item and discuss ways in which instructors can help with the development process of this assessment while incorporating it into their classrooms. Faculty administering the assessment would receive detailed feedback about their class’s overall performance with recommendations for how to adjust instruction to improve student outcomes.

A Knowledge-in-Use Assessment for Upper-Division Thermal Physics

We present preliminary mixed-methods results for an experiment upon a first-semester senior undergraduate electromagnetism course for physics majors, in which 25 students were given explicit incentive to rework mistakes from unit exams in a first-semester senior-level electromagnetism course. Three unit exam problems were revisited on the final exam. Initial quantitative results for one of the three problems (P1) showed a strong effect from unit exam to final, between students who reworked problems and students who chose not to; however, the other two problems (P2 and P3) presented a ceiling effect on unit exam performance that prevented pre-post analysis. Follow-up interviews with a small sample of students suggest a strong recall of their attempts on problems P1 and P2 despite being over a year removed from said exams; however, some did not recognize mistakes. We conclude by discussing plans for analysis of current/future data and adjustments to this ongoing study.

Rework and Recall: Exam Performance in Upper-division Electromagnetism

In order to help our students better understand the conceptual connections between spin states and wavefunctions in our junior-level, spins-first quantum course, we have recently begun to emphasize the use of completeness relations to write a state in a particular basis. We describe completeness relations as “special forms of 1” that can be used to project a quantum state vector onto a basis. Using a discrete spin bases, the expansion coefficients are interpreted as probabilities amplitudes. Using a continuous position basis, these probability amplitudes get “smeared out” to become a “probability amplitude density” (a.k.a., wavefunction), similar to how discrete point masses go to mass densities. In this talk, we will share the in-class activities and homework tasks we’ve developed to help students understand make these connections.


Using Completeness Relations to Help Students Understand Wavefunctions

Open and Individualized - Mechanics Homework Problems Project Using WeBWorK

Individualized homework problems delivered over the web are an effective way for students to learn first year mechanics. This is not news, but I learned how effective it was and that it is worth spending the time developing more problems as part of an open community. WeBWorK is an open-source on-line homework system that gives students instant feedback. It has better quiz options than most Learning Management Systems. WeBWorK has been used by the mathematics community for decades, but there are not many physics problems in the Open Problem Library (OPL) and less than 100 of the type needed for first and second-year physics and engineering students. I am a physics instructor at a two-year teaching college, but I ended up working with an engineering professor and coop students at UBC, a large research university We hope to have more people join us in this worthwhile project. 
I will present what I learned about WeBWorK, supervising coop students to create questions, and working with a professor from a large university to create open educational resources.

Open and Individualized - Mechanics Homework Problems Project Using WeBWorK

With the rise of the flipped (active) classroom, in addition to more courses moving online, the use of video as a form of instruction has increased substantially. This raises the question about the impact of this method of delivery on student learning. Under NSF funding, we have developed and evaluated multiple interactive video-enhanced tutorials (IVETs). The IVETs involve web-based activities that lead students through a problem solution using expert-like problem-solving approaches. As part of the IVET evaluation, we assigned one group of students to complete the IVETs as homework, while another group watched a video summary of the problem solving process. Both groups later completed a follow-up problem as a means of measuring impact on learning. Significant learning gains were observed for students in the IVET group compared to the Video-only group. Results from multiple IVETs will be shared along with suggestions for making videos more mentally engaging for students.
*Work supported by the NSF IUSE Program (DUE #1821396)


Video versus Interactive Video for Impact on Learning

When planning to take my calculus-based introduction to mechanics online, I had many small concerns, and two huge ones: tests and labs. In both cases, the solutions I found were imperfect, but contained elements that were improvements over the pre-pandemic versions. In this talk, I will focus on the labs. I replaced hands on labs with a mixture of simulations, computational exercises and labs using the sensors in students’ smartphones. While many students missed the “lab group experience” they were excited by the additional flexibility afforded by these labs, particularly those using their phones. I will discuss the benefits and shortcomings of all three of these lab formats but focus primarily on the phone-based labs, which I will be continuing to use post-pandemic.

Updating mechanics labs with technology for the pandemic and beyond

Nowadays computation stands alongside theory and experiment as one of the pillars of modern science, which is reflected in the fact that research and industry rely heavily on technology and computation. Therefore, we need to prepare graduates to integrate computation within their underlying discipline. In this study, we look at how academics across the College of Science at an Irish University use computational practices in their research. This will inform the design of a first-year undergraduate science course aimed at emphasizing the relevance of computational practices in science, by introducing them to authentic problems across the areas of science where computation is used and to make students competitive graduates in their respective fields.

A Collaborative Approach to Designing an Introductory Computational Science Course

Computational modeling and video analysis are two powerful tools in the physics classroom for helping students analyze and model real-world phenomena. When we pair the two of these together in one web-based platform, students can use video analysis to construct a computational model that reproduces the data they measure from the video and gain new physical insights and understandings. Pivot interactives is one platform that allows for the integration of video analysis side by side with computational tools like Tychos, Glowscript, and Pyret.


Computational Modeling & Video Analysis in One Easy Environment

Implementing Positive Psychology in International Physics Masterclass with LHC Data

Mission to the moon, rendezvous with the Intl. Space Station are some of the missions students must complete - they will learn orbital mechanics physics and apply what they have learned to launching a spacecraft and traveling to other planets and moons. Presentation also, covers model rocket physics (with and without air) design, simulation and launch using a simulator.

Understanding exotic gravitational wave orbits with effective potentials

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