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The acoustic impedance is an important quantity in characterizing the behavior of an acoustic system. The acoustic impedance of musical instruments determines the instrument’s response to excitation, reveals resonance frequencies, and shows which notes can be played. While the acoustic impedance is easy to calculate for simple shapes, it is very complicated to do so for the shapes of real musical instruments. This talk outlines an interactive method of calculation of the acoustic impedance of an arbitrary shape of an axially symmetric air column by approximating the air column by a series of cylindrical elements. We demonstrate the feasibility of the method by comparing the iterative result with the closed form solution for air columns of simple shape. Moreover, we discuss the calculation of the acoustic impedance of a trumpet-like instrument and show how different parts of the instrument affect its acoustic behavior.

AAPT SM 20

Iterative Calculation of the Acoustic Impedance of a Trumpet-Like Musical Instrument

physical acoustics

acoustic impedance

computational physics

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The 2020 AAPT Virtual Summer Meeting brought together physics educators from around the globe to learn about the latest in physics theory, research methodology and education from leaders in their field. The program featured plenary speakers, sessions, workshops and many special activities.

For more information please visit the 2020 AAPT Virtual Summer Meeting page at: https://www.aapt.org/Conferences/SM2020/index.cfm.


The 2020 AAPT Virtual Summer Meeting brought together physics educators from around the globe to learn about the latest in physics theory, research methodology and education from leaders in their field. 

Since 2013 I have run a multiple-day, focused summer outreach program. The goal of the program is to dispel biases and show junior high and high school aged girls that they have the ability and opportunity to become scientists. The event is designed to give approximately 16 young women an intense, multi-day experience. The small size of the group and the length of the activity allows them to understand and perform in-depth activities. Insights I have gained about successfully running this type of activity will be discussed.

BYU/UVU-GAL: A Focused Outreach Activity for Young Women

Because electric fields cannot be touched or seen, simulations are often utilized to build students' understanding of them by providing them with a visual experience of electric fields and the motion of test charges through them. The objective of the simulation is to improve students’ qualitative understanding of how electric fields are impacted by the charges around them by creating a dynamic representation of the electric field lines, field vectors, equipotential lines, and the voltage created by the charges on screen. After creating a charge configuration, students can observe the motion of test charges through the electric field. The simulation was built in JavaScript so it will run on most browsers on a computer or mobile device. The simulation is intended to be used by college students taking introductory physics courses. A study of the impact on students' understanding and attitude will be analyzed in future work.

Dynamic Simulation to Help With the Understanding of Electric Fields

Interpreting and understanding the way students use and understand the mathematics used in physics is a central theme in Physics Education Research. Physical phenomena described by partial differential equations (PDEs) provide a promising context to study how students combine physics and mathematics. An example is the description of heat flow and temperature distribution in a one-dimensional rod, which can be described by the (1D) heat equation, together with an initial condition (IC), and boundary conditions (BCs). In this contribution, we present data from an interview study where we gave students the mathematical description of a system (PDE, IC and BCs) together with the analytical solution. We asked to describe the time evolution of the system, both in mathematical and physical terms. Our analysis shows that students’ reasoning is mainly mathematical with little reference to the underlying physics and that most students do not connect their mathematical statements to physical processes.

Relating solutions to the heat equation to the underlying physics

First, a fully comprehensive lab-manual for physics-I (kinematics) online-class was developed by using video-analysis and simulations. Only open educational resources (OER) were used to develop the lab manual. New lab manuals for ten experiments were written to investigate important basic concepts of kinematics class. Online lab classes are done synchronous format (at regular meeting time) online-live. During online meetings, the instructor work on at least two shared windows simultaneously one for writing and explanation (use the tablet mode of a dual-mode laptop) and one to access the lab manual. The instructor works with the students to collect the data by using virtual tools and demonstrate further data analysis, graphing, curve-fitting, calculations, and error analysis with the MS-Excel software package. Finally, students were required to compile a full lab report at a scientific standard and submitted to the learning-management-system (LMS) via plagiarism-checker. The learning outcome was analyzed by quizzes and exams.

Development of Physics-I (Kinematics) Lab-class for Virtual (fully online) Delivery

We are finishing development of around twenty video-based activities for topics in mechanics at the introductory undergraduate level (also useful for high school physics and AP physics I). Videos were taken of real moving objects - like a basketball, a girl on a playground slide, a billiard ball collision, a girl on a swing and even a diving board undergoing damped oscillatory motion to name a few. Videos were analyzed using Logger Pro. Each activity has the actual video, tracked motion images, graphs of relevant quantities and physics concept questions that rely primarily on getting information from the graphs. These will be integrated into the Expert TA system before the start of the fall semester. They can be used for homework where students will gain skills in estimating and interpreting graphs. They can also be used to replace some lab experiences students might miss because of online teaching.

VIDEO BASED GRAPHICAL ANALYSIS PROBLEMS - A supplement or replacement for lab experience in mechanics

How data guided pedagogical changes can help traditionally under-served populations

Doing Flight Physics with Smartphones and Real-time Data Analysis

QuarkNet High School students and teachers have collected data on cosmic ray muons. Their data is available to all on the i2u2.org site. QuarkNet has made available several experimental analysis tools to use with the existing 100K data files. In a remote learning environment, students can design their own experiment to measure fundamental properties like the speed or lifetime of muons, changes in the cosmic ray rate over time or with angle of orientation, or investigate the size of cosmic ray air showers.

QuarkNet Supports Remote Analyses of Cosmic Rays for High Schools

Despite limiting access to applicants from underrepresented racial and ethnic groups, the practice of using hard or soft GRE cutoff scores in physics graduate program admissions is still a popular method for reducing the pool of applicants. The present study considers whether the undergraduate institutions of applicants have any influence on the admissions process by modelling a physics GRE cutoff score with application data from admissions offices of five Midwestern universities. Two distinct approaches based on inferential and predictive modelling are conducted. While there is some disagreement regarding the relative importance between features, the two approaches largely agree that to include institutional information significantly aids the analysis. Both models identify cases where the institutional effects are comparable to factors of known importance such as gender and undergraduate GPA. As the results are stable across many cutoff scores, we advocate against the practice of employing physics GRE cutoff scores in admissions.

How do undergraduate institutions matter for physics GRE cutoff scores?

During the Spring 2020 quarter, the COVID-19 pandemic precluded access to our acoustics laboratory. In response, I redeveloped the experiments of our acoustics lab course in several ways. For some introductory activities, I employed videos to show basic concepts and methods in place of lab demonstrations and used applets to maintain some student interactivity. However, for most of the specialized experiments, I was able to draw upon past student work archived in electronic laboratory notebooks to extract photos, setup details, and experimental data sets. I then used that information to write activities that described the experimental methods, but required the current students to visualize, analyze, and interpret the data. To facilitate the course remotely, I used electronic laboratory notebooks to deliver and receive content. Preliminary indications are that the students are obtaining a similar understanding of the experimental methods and possibly better understanding of the data analysis than previous students.

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