2015 BFY Proceedings
Dates: July 22-24, 2015
Editors: Melissa Eblen-Zayas, Ernest Behringer, and Joseph Kozminski
The theme of the 2015 BFY conference was "Constructing Great Instructional Lab Experiences." This conference highlighted effective lab curricula, teaching methods, and experiments. In addition to the papers addressing this year’s theme, the remainder of the papers represent the diversity of approaches within the Advanced Labortory community and help this volume fulfill its purpose of providing a snapshot of the field.
Readership: Advanced laboratory instructors (faculty, post-doctoral students, and graduate students); researchers in fields utilizing detection equipment.
Table of Contents
PEER REVIEWED MANUSCRIPTS (27)
First Author Index
Ackerman · Bayram · Beck · Bobowski · Burnham · Eblen-Zayas · Grove · Heffner · Hofstetter · Holmes · Krantz · Lott · Masters · Mayonado · McCann · McKeever · O'Leary · Parks · Pengra · Polak · Roach · Robinson · Stein · Tagg · Vonk · Yoder
Integrating Commercial Solar Panels in the Physics Curriculum
Agnes Scott College has a significant number of sustainability initiatives, including a hydrogeothermal HVAC system and five solar photovoltaic arrays. The Physics and Astronomy department is in the process of integrating alternative energy into our curriculum and public outreach activities. During Laboratory Physics (PHY311), two student teams pursued self-designed projects to model the efficiency of the 6kW solar array installed at a fixed tilt on the flat roof of the college Observatory. During the summer of 2015, two student research scholars constructed a movable mount and data acquisition system for a stand alone panel identical to those on the roof, to allow control and recording of individual variables such as sun angle, temperature, and other weather conditions. In future years, students will learn about the solar panels in Analog Electronics (PHY242) and present solar power to K-12 school groups touring our Observatory.
N. L. Ackerman, A. J. Lovell, M. Franklin, R. Cupp, Y. (. Wan, V. Wood, C. Day, and E. Whisnant, Integrating Commercial Solar Panels in the Physics Curriculum, 2015 BFY Proceedings [College Park, MD, July 22-24, 2015], edited by M. Eblen-Zayas, E. Behringer, and J. Kozminski, doi:10.1119/bfy.2015.pr.001.
A Spectral Analysis of Laser Induced Fluorescence of Diatomic Iodine
When optically excited, diatomic iodine absorbs in the 490 to 650-nm visible region of the spectrum and, after radiative relaxation, it displays an emission spectrum of discrete vibrational bands at moderate resolution. This makes laser-induced fluorescence spectrum of molecular iodine especially suitable to study the energy structure of homonuclear diatomic molecules at room temperature. In this spirit, we present a rather straightforward and inexpensive experimental setup and the associated spectral analysis which provides an excellent exercise of applied quantum mechanics t for advanced laboratory courses. The students would be required to assign spectral lines, ll a Deslandres table, process the data to estimate the harmonic and anharmonic characteristics of the ground vibronic state involved in the radiative transitions, and henceforth calculate a set of molecular constants and discuss a model of molecular vibrator.
S. B. Bayram and M. V. Freamat, A Spectral Analysis of Laser Induced Fluorescence of Diatomic Iodine, 2015 BFY Proceedings [College Park, MD, July 22-24, 2015], edited by M. Eblen-Zayas, E. Behringer, and J. Kozminski, doi:10.1119/bfy.2015.pr.002.
An entangled state of a two-particle system is a quantum state that cannot be separated—it cannot be written as the product of states of the individual particles. One way to tell if a system is entangled is to use it to violate a Bell inequality (such as the Clauser-Horne-Shimony-Holt, CHSH, inequality), because entanglement is necessary to violate these inequalities. However, there are other, more efficient measurements that determine whether or not a system is entangled; an operator that corresponds to such a measurement is referred to as an entanglement witness. We present the theory of witness operators, and an undergraduate experiment that measures an entanglement witness for the joint polarization state of two photons. We are able to produce states for which the expectation value of the witness operator is entangled by more than 160 standard deviations.
M. N. Beck and M. Beck, Witnessing Entanglement, 2015 BFY Proceedings [College Park, MD, July 22-24, 2015], edited by M. Eblen-Zayas, E. Behringer, and J. Kozminski, doi:10.1119/bfy.2015.pr.003.
Screening Electric Fields using a Tube of Water: The Transition from Conductive to Dielectric Screening
An experiment that investigates the transition from conductive to dielectric screening of electric fields by a tube of water has been designed for senior physics undergraduates. A parallel-plate capacitor is used to generate a uniform electric field. Two concentric acrylic plexiglass tubes pass perpendicularly through the electric field generated between the plates. The region between the tubes can be filled with air or water. An electrode, suspended within the inner plexiglass tube, is used to sense the electric potential at its location. The sensor is designed so that it can be rotated to measure the potential at a second symmetric position. From the difference in the two potentials, the frequency dependence of the magnitude and phase of the electric field can be determined. With deionized water between the tubes, the magnitude and phase of the interior electric field was measured from 100 Hz to 300 kHz. The high-pass filter frequency response expected for a dielectric tube with non-negligible conductivity was observed. Fits to the data yielded a very reasonable experimental value for the ratio of the water’s conductivity to its dielectric constant.
J. S. Bobowski and J. D. Vos, Screening Electric Fields using a Tube of Water: The Transition from Conductive to Dielectric Screening, 2015 BFY Proceedings [College Park, MD, July 22-24, 2015], edited by M. Eblen-Zayas, E. Behringer, and J. Kozminski, doi:10.1119/bfy.2015.pr.004.
Using Split-Ring Resonators to Measure Complex Permittivity and Permeability
This paper describes how to measure the complex permittivity and permeability of materials using split-ring resonators. High-Q split-ring resonators, which can be modelled as LRC circuits, are easy to fabricate and can be used to measure electromagnetic material properties at frequencies that span approximately 10 MHz to 2 GHz. If the resonator is submerged in a liquid/suspension, its resonant frequency and quality factor will be be modified from the in-air values by factors that depend on the relative permittivity and permeability of the liquid/suspension. General expressions for the resonator’s frequency response are derived. Unlike an LRC circuit, the resonator’s response is not strictly Lorentzian. However, a wide variety of cases for which the response is approximately Lorentzian are explored. For each of these cases it is demonstrated that the real and imaginary components of the relative permittivity and permeability can be extracted from the in-air and in-liquid/suspension resonant frequencies and quality factors.
J. S. Bobowski, Using Split-Ring Resonators to Measure Complex Permittivity and Permeability, 2015 BFY Proceedings [College Park, MD, July 22-24, 2015], edited by M. Eblen-Zayas, E. Behringer, and J. Kozminski, doi:10.1119/bfy.2015.pr.005.
An Intensive Short Course on Atomic-Force Microscopy
A course on atomic-force microscopy (AFM) that has been previously taught to undergraduates and graduate students over a semester or a half-semester was taught in short-course format. The course structures are compared, the resources for the short course are described, the short course is evaluated, and recommendations are given.
N. A. Burnham, A. Arcifa, M. Divandari, C. Mathis, S. N. Ramakrishna, and N. D. Spencer, An Intensive Short Course on Atomic-Force Microscopy, 2015 BFY Proceedings [College Park, MD, July 22-24, 2015], edited by M. Eblen-Zayas, E. Behringer, and J. Kozminski, doi:10.1119/bfy.2015.pr.006.
Comparing Electronic and Traditional Lab Notebooks in the Advanced Lab
Two years ago, the advanced lab course at Carleton College switched to using electronic lab notebooks (ELNs) instead of traditional paper lab notebooks. In the wake of this change, a survey of students in the class shows that over 80% of the students would recommend other science classes use ELNs. The survey also highlights what students perceive as strengths and weaknesses of each notebook format. This paper discusses the student impressions of the relative merits and drawbacks of ELNs as well as providing an overview of the reasons for switching to ELNs and the considerations in selecting ELN software.
M. Eblen-Zayas, Comparing Electronic and Traditional Lab Notebooks in the Advanced Lab, 2015 BFY Proceedings [College Park, MD, July 22-24, 2015], edited by M. Eblen-Zayas, E. Behringer, and J. Kozminski, doi:10.1119/bfy.2015.pr.007.
From a Low Cost Spectrograph to a High Resolution Spectrograph
We have been using low-cost spectrographs called shoebox spectrographs for a few years. In the process of our study, we decided to make a spectrograph using the same basic optical design but with quality optical parts. This new spectrograph was found to be easily aligned, very accurate (~ 0.2 Angstrom accuracy), and enables intermediate and advanced students to study molecular spectral lines. We will present theory of operation as well as accurate photographs of molecular spectra.
T. T. Grove, From a Low Cost Spectrograph to a High Resolution Spectrograph, 2015 BFY Proceedings [College Park, MD, July 22-24, 2015], edited by M. Eblen-Zayas, E. Behringer, and J. Kozminski, doi:10.1119/bfy.2015.pr.008.
A Differential Thermal Analysis Apparatus for Exploring the Glass Transition
Glass is among the most common materials in our everyday lives. And yet the science behind this interesting, complex and ubiquitous material is seldom considered in the undergraduate science curriculum. The glass transition (Tg) is both a fundamental and defining concept in understanding the glassy state. To facilitate the experimental exploration of this important topic we have developed a simple home-built apparatus for measuring the Tg and the associated relaxation phenomena. The simple differential thermal analysis (DTA) apparatus requires only basic mechanical and electronic construction skills yet provides excellent resolution of the Tg for the low temperature sugar glasses examined. We also demonstrate the strong effect of thermal history on Tg, including both the effect of cooling rate and aging. This apparatus provides an interesting and intuitive path to the student’s exploration and understanding of the glassy state and provides a resource for deeper, independent and open-ended study of the relaxation phenomena, especially appropriate for an advanced undergraduate laboratory.
W. R. Heffner, A Differential Thermal Analysis Apparatus for Exploring the Glass Transition, 2015 BFY Proceedings [College Park, MD, July 22-24, 2015], edited by M. Eblen-Zayas, E. Behringer, and J. Kozminski, doi:10.1119/bfy.2015.pr.009.
Micro-ESR As A Laboratory Teaching Tool
Active Spectrum’s Micro-ESR spectrometer is a portable (10 kg), X-band (9.7 GHz) CW benchtop electron spin resonance spectrometer. The Micro-ESR is an ideal tool for teaching undergraduate chemistry and physics labs. This instrument enables classroom demonstrations of both simple topics such as the role of free radicals in everyday life to far less intuitive subjects including chemical bonding, electron density, spin-orbit coupling, spin-spin exchange, and forbidden transitions. The spectrometer also allows user control over many important parameters, so students can experiment with different acquisition schemes. The Micro ESR is thus ideal for an instrument lab. All data are automatically saved, and can be imported into any spreadsheet for additional processing or analysis. Offline processing software can also be used to analyze and post-process data, perform quantitative analyses, simulations and other basic functions.
C. Hofstetter and J. R. White, Micro-ESR As A Laboratory Teaching Tool, 2015 BFY Proceedings [College Park, MD, July 22-24, 2015], edited by M. Eblen-Zayas, E. Behringer, and J. Kozminski, doi:10.1119/bfy.2015.pr.010.
Assessing modeling in the lab: Uncertainty and measurement
Many introductory physics labs include goals related to learning about measurement uncertainty or error propagation. In this article, we present evidence from a new survey about experimentation and modeling in physics labs indicating that student difficulties with these concepts may stem in part from the language used. We demonstrate that students conflate measurement uncertainty, systematic effects, and measurement mistakes under a single umbrella. After a course that explicitly distinguished these three terms, students' paid more attention to precision and sources of random variability, rather than systematics or experimenter mistakes. We use this preliminary analysis to evaluate the survey as an instrument to assess learning in physics labs.
N. G. Holmes and C. E. Wieman, Assessing modeling in the lab: Uncertainty and measurement, 2015 BFY Proceedings [College Park, MD, July 22-24, 2015], edited by M. Eblen-Zayas, E. Behringer, and J. Kozminski, doi:10.1119/bfy.2015.pr.011.
Nonlinear Dynamics on the Cheap in the Junior Laboratory
This past spring (2015) three of us (RK, RT, JC) team-taught a Junior level laboratory in which physics majors are required, over two semesters, to complete experiments in 8 out of 10 main topic areas of physics. As of the beginning of the spring 2015 semester, a satisfactory Mechanics/Nonlinear Dynamics experiment supplied with instructions had not been identified. Towards the end of the semester two Metropolitan State University of Denver students (NH, JZ) expressed an interest in investigating the nonlinear dynamics of Duffing’s oscillator. Below, we describe the results of their efforts.
R. Krantz, N. Hoen, J. Zimmerman, R. Tagg, and J. Carlson, Nonlinear Dynamics on the Cheap in the Junior Laboratory, 2015 BFY Proceedings [College Park, MD, July 22-24, 2015], edited by M. Eblen-Zayas, E. Behringer, and J. Kozminski, doi:10.1119/bfy.2015.pr.012.
A Peer Review Writing Workshop in the Advanced Lab
At Denison University students in the advanced lab, PHYS 312: Experimental Physics, write substantial manuscript-style laboratory reports on three major experiments carried out during the semester. Thoughtful peer review can be an effective way to enhance student learning and confidence in their scientific writing skills. The development of purposeful assignments and subsequent class discussions of scientific writing and the peer review process, the execution of a peer review workshop, and samples of student work are presented in this paper.
M. B. Lott, A Peer Review Writing Workshop in the Advanced Lab, 2015 BFY Proceedings [College Park, MD, July 22-24, 2015], edited by M. Eblen-Zayas, E. Behringer, and J. Kozminski, doi:10.1119/bfy.2015.pr.013.
Low-Cost Coincidence Counting Apparatus For Single Photon Optics Investigations
We have recently started investigating single photon experiments for our advanced laboratory and quantum mechanics classes. For a small department, the expenses of much of the apparatus is daunting. As such, we look for places where we can reduce the costs while still providing benefits for our students. One of the places where there can be some cost savings are in the coincidence counting unit. The coincidence counting unit is a critical piece of the investigation, and while not the most expensive component, cost savings are still available. We have developed a low-cost coincidence counter (less than $50) based on a Cypress Programmable System on a Chip (PSoC). The PSoC is quite flexible and has both microcontroller as well as FPGA like capabilities which enable us to build the coincidence detection and the counter. The design process and several investigations will be presented.
M. F. Masters, T. Heral, and K. Tummala, Low-Cost Coincidence Counting Apparatus For Single Photon Optics Investigations, 2015 BFY Proceedings [College Park, MD, July 22-24, 2015], edited by M. Eblen-Zayas, E. Behringer, and J. Kozminski, doi:10.1119/bfy.2015.pr.014.
Investigation Of The Bragg-Snell Law In Photonic Crystals
We present an optical experiment on photonic crystals suitable for an advanced physics laboratory course or a senior capstone project. Photonic crystals are periodically ordered composite systems made of materials that have different dielectric constants, and can be arranged in one, two, or three dimensions. They are characterized by a bandgap that depends on the size, arrangement and dielectric constant of the microstructures that make up the crystal. In addition, the bandgap spectrally shifts with the angle of incident light. These observations are captured by the Bragg-Snell law. In this paper, we describe a vertical deposition method for growing photonic crystals from a water suspension of polystyrene microspheres, as well as a simple transmission experiment that students can perform using a USB-spectrometer to explore the Bragg-Snell law.
G. Mayonado, S. M. Mian, V. Robbiano, and F. Cacialli, Investigation Of The Bragg-Snell Law In Photonic Crystals, 2015 BFY Proceedings [College Park, MD, July 22-24, 2015], edited by M. Eblen-Zayas, E. Behringer, and J. Kozminski, doi:10.1119/bfy.2015.pr.015.
Introducing students to single photon detection with a reverse-biased LED in avalanche mode
An inexpensive experiment using a reverse-biased LED as an avalanche photodiode is described. The experiment is rich in physics topics and experimental techniques, allowing students to explore the statistics of random events, basic discriminator circuits, and the behavior of avalanche photodiodes.
L. I. McCann, Introducing students to single photon detection with a reverse-biased LED in avalanche mode, 2015 BFY Proceedings [College Park, MD, July 22-24, 2015], edited by M. Eblen-Zayas, E. Behringer, and J. Kozminski, doi:10.1119/bfy.2015.pr.016.
The Thermographic Phosphor Labkit
The thermographic phosphor (TGP) Labkit is a flexible instrument for students beyond the first year and is also a useful laboratory tool for physics and research and development. It aids in teaching and demonstrating a number of useful concepts and skills. Students will learn important aspects of optical physics and spectroscopy. By producing fluorescence and measuring its characteristics versus temperature, students will become familiar with atomic energy levels, lifetimes, radiative and non-radiative transitions, spectral bands and linewidth, spectral distribution, and absorption. In addition, measurements involve optics, electro-optics, and electronic instrumentation. The Labkit contains an ultraviolet light emitting diode of 365 nm that illuminates a thin phosphor layer. The phosphor adheres to a copper plate in intimate contact with a Peltier heater/cooler that covers 0 to 100 °C. A thermocouple attaches to the copper plate to monitor temperature. The Labkit allows for controlling the pulse duration of the LED and the rate of repetition. Representative signals from 10 to 55 °C are presented and the resulting well behaved lifetime versus temperature plot. Results of separate measurements at 10 °C indicate repeatability. Detector linearity is demonstrated over a factor of eight in detector gain. Practice and familiarity with common laboratory and industry tools such as thermocouples, Peltier devices, and photomultiplier detectors also contribute to the educational objectives. Finally, in the course of exercising the instrument, the student will learn the practical skill of temperature measurement and control.
M. M. McKeever, M. R. Cates, S. W. Allison, D. L. Beshears, A. Akerman, M. B. Scudiere, and J. E. Parks, The Thermographic Phosphor Labkit, 2015 BFY Proceedings [College Park, MD, July 22-24, 2015], edited by M. Eblen-Zayas, E. Behringer, and J. Kozminski, doi:10.1119/bfy.2015.pr.017.
LCphysX: Teaching Undergraduate Physics Majors Multi- Media Science Communication Skills for Public Outreach
LCphysX is a web-based platform designed with the primary purpose of teaching undergraduate physics majors in upper-level laboratory courses multi-media science communication skills for engaging in public outreach. Compelling arguments have recently been made for the need to train future scientists to engage with a popular audience using digital media. Developed in partnership with Lewis & Clark College’s (LC) Library Digital Initiatives team, LCphysX features short student-produced videos that present projects and experiments from upper-level lab courses to a popular audience. LC’s unique Advanced Laboratory course provides students with the opportunity to design, build, and test their own physics projects, and for many students, their project is the main cumulative achievement of their physics education. Indexed, searchable videos on the LCphysX website permanently archive LC physics projects and serve as pedagogical reference points and inspiration for physics faculty and students at LC and beyond. In addition, as the Advanced Laboratory course is a requirement for the LC physics major, all physics graduates will leave LC with an active “link” for their resumé that showcases their technical achievements, as well as their ability to communicate scientific ideas. Assessment of LCphysX's effectiveness in engaging the public will include feedback solicited from high school students across the United States.
S. O'Leary and P. Abbaspour, LCphysX: Teaching Undergraduate Physics Majors Multi- Media Science Communication Skills for Public Outreach, 2015 BFY Proceedings [College Park, MD, July 22-24, 2015], edited by M. Eblen-Zayas, E. Behringer, and J. Kozminski, doi:10.1119/bfy.2015.pr.018.
Compton Scattering of Cs-137 Gamma Rays
The Compton Effect is an ideal physics experiment for the advanced modern physics lab. The relevance of this experiment and an approach to teaching about this lab are discussed. The apparatus for this experiment consists of a Cs-137 gamma source located in a lead howitzer, a goniometer to precisely locate a NaI detector at different angles to make gamma energy measurements, and a multichannel analyzer system that includes a high voltage supply and amplifiers. The lead howitzer and goniometer were specially constructed, and information to reproduce them is given. Typical results are presented.
J. E. Parks and C. P. Cheney, Compton Scattering of Cs-137 Gamma Rays, 2015 BFY Proceedings [College Park, MD, July 22-24, 2015], edited by M. Eblen-Zayas, E. Behringer, and J. Kozminski, doi:10.1119/bfy.2015.pr.019.
Exploring the Rotating Reference Frame in Off-Resonance Pulsed NMR
Understanding the physics of pulsed nuclear magnetic resonance (NMR) is eased by a transformation to a rotating reference frame. Within such a frame, coincident with the applied RF H1 field that rotates about the static H0 field, the net effective magnetic field is static, and the dynamics of spin precession yield to simple geometric analysis. In most treatments of NMR the resonant frame, defined by the Larmor frequency ω0 = γH0, is used. In this frame the effective field reduces to H1 only, and one can immediately derive the pulse widths needed to optimize the free induction decay (FID) signals—the so-called π/2 and 3π/2 pulses. But what happens in a frame that is off resonance? The same geometrical analysis shows that as the frequency of H1 is detuned from resonance, (1) the pulse width needed to maximize the FID signal increases for “π/2” pulses and decreases for “3π/2” pulses, (2) at a critical value of detuning, the widths of both pulses converge to p2 times the width of the on-resonance π/2 pulse, (3) this critical detuning is equal to the Larmor frequency of H1, and (4) the maximum amplitude the FID signal is unchanged as long as the detuning is less than the critical value. Detuning further causes the optimum pulse width to decrease and the magnitude of the FID signal to drop. This experiment helps students explore a wider range of predictions inherent in the classical model of NMR, and it can be performed on the popular TeachSpin PS1 apparatus with no extra equipment.
D. B. Pengra, Exploring the Rotating Reference Frame in Off-Resonance Pulsed NMR, 2015 BFY Proceedings [College Park, MD, July 22-24, 2015], edited by M. Eblen-Zayas, E. Behringer, and J. Kozminski, doi:10.1119/bfy.2015.pr.020.
An Optics Laboratory Module on Image Formation, Aberrations, and Lens Design
To foster a deeper understanding of advanced laboratory concepts, weekly laboratories in an upper-division optics course have been replaced by modules, where students study a single topic over the course of several weeks. This culminates in a laboratory report written according to the American Institute of Physics style manual. One module covers image formation, aberrations and lens design. The students measure the mechanical properties of a lens and the optical properties of the glass. With this information, they build a virtual lens using ray-tracing software and compare results within the virtual environment to those measured in the laboratory.
R. D. Polak and N. M. Pflederer, An Optics Laboratory Module on Image Formation, Aberrations, and Lens Design, 2015 BFY Proceedings [College Park, MD, July 22-24, 2015], edited by M. Eblen-Zayas, E. Behringer, and J. Kozminski, doi:10.1119/bfy.2015.pr.021.
Sequential Introduction of Data Analysis Methods in the Modern Lab
A major goal of many intermediate physics labs is learning methods of data analysis. In our Modern Lab course we introduce these methods in a planned sequence, with labs explicitly designed to match the sequence, so that students learn increasingly more sophisticated methods as the semester progresses. The first lab has them investigate repeated measurements of a single quantity (the speed of electromagnetic pulses and speed of light) and introduces the concept of error propagation. In the second lab they use a functional relation (lambda vs. sinq ), for calibration of a diffraction grating, using residuals to optimize the fit. Later labs introduce Gaussian and Poisson probability distributions, and Least-Squares fitting of functions (including non-linear minimization). In addition, we provide here a few examples of how either methods or experiments can be adapted in order to support a coherent sequence of learning.
T. Roach, Sequential Introduction of Data Analysis Methods in the Modern Lab, 2015 BFY Proceedings [College Park, MD, July 22-24, 2015], edited by M. Eblen-Zayas, E. Behringer, and J. Kozminski, doi:10.1119/bfy.2015.pr.022.
Effectiveness of flipped classroom techniques in an advanced laboratory physics course
We report preliminary observations of changes in responses to student surveys over a five year period in an advanced laboratory course for third-year physics majors at the Massachusetts Institute of Technology. This period spanned the introduction of curriculum reforms which included the use flipped classroom techniques - facilitated by the OpenEdX platform — for those aspects of the course material which had previously been taught by direct instruction, such as data analysis techniques and basic laboratory instrumentation. Not all variables of the classroom environment were controlled during the study period, so flipped classroom techniques cannot be identified with full confidence as the cause of the measured changes. Survey data was collected using the E-CLASS and institutionally administered subject evaluations. Improvements were observed in some metrics of interest to the course’s strategic goals — notably in students’ self-reported hours per week spent on coursework and in the overall rating of the course — while negative or null results were observed in other metrics of interest.
S. P. Robinson, G. Roland, C. Bosse, and E. Zayas, Effectiveness of flipped classroom techniques in an advanced laboratory physics course, 2015 BFY Proceedings [College Park, MD, July 22-24, 2015], edited by M. Eblen-Zayas, E. Behringer, and J. Kozminski, doi:10.1119/bfy.2015.pr.023.
Undergraduate Advanced Laboratory Studies on Supersonic Nozzle Flow
Undergraduate studies are carried out in the advanced laboratory to examine the supersonic flow from an axisymmetric converging-diverging nozzle. Flow is initiated by the rupture of a diaphragm and exits from a small nozzle (with a 0.95 cm exit diameter) into standard atmospheric conditions from a one gallon (3.875 liter) tank. Compressible flow simulations are carried out for the nozzle and comparisons are made to experiments based on high-speed video shadowgraph imaging and dual-beam interferometry. The multifaceted approach based on simulation and experiments exploits the distinct strengths of the different methods to provide a more comprehensive description of the nozzle flow than is achievable by the individual approaches.
K. R. Stein, C. D. Fredrick, and R. W. Peterson, Undergraduate Advanced Laboratory Studies on Supersonic Nozzle Flow, 2015 BFY Proceedings [College Park, MD, July 22-24, 2015], edited by M. Eblen-Zayas, E. Behringer, and J. Kozminski, doi:10.1119/bfy.2015.pr.024.
Technical Competencies – A Versatile Framework for Learning Practical Knowledge
Students need a wide array of practical skills and knowledge in order to pursue advanced laboratory work, research, innovation, and technical jobs in industry. This knowledge begins with tool and shop use and extends to a capacity for basic electronics design, construction, and testing. Beyond these common skills, students need to come up to speed quickly on specialized techniques specific to a particular problem: examples include vacuum technique, plumbing, use and calibration of sensors, motor control, pneumatic actuators, etc. We provide a physical inventory, a web site, and a learning model that provides access to an expanding array of practical knowledge topics. The goal of this ongoing project is to develop a versatile framework for students to obtain and certify a personal repertoire of technical competencies.
R. Tagg, Technical Competencies – A Versatile Framework for Learning Practical Knowledge, 2015 BFY Proceedings [College Park, MD, July 22-24, 2015], edited by M. Eblen-Zayas, E. Behringer, and J. Kozminski, doi:10.1119/bfy.2015.pr.025.
Using Digilent’s Basys3 FPGA board with LabVIEW for single-photon counting
The Basys3 board produced by Digilent and featuring the Artix-7 FPGA (Field Programmable Gate Array) promises to provide the fast electronic signal processing required to perform single-photon counting. The Basys3 compares favorably in terms of cost, speed, and convenience to the Altera-brand FPGA’s that have been described by other authors. LabVIEW provides a flexible and convenient way to control the FPGA board and to graphically represent what is happening with the various counts in real time. Details about how to use the Basys3 board and information about how to interface the board with LabVIEW in the context of a single-photon counting experiment are described.
M. T. Vonk, Using Digilent’s Basys3 FPGA board with LabVIEW for single-photon counting, 2015 BFY Proceedings [College Park, MD, July 22-24, 2015], edited by M. Eblen-Zayas, E. Behringer, and J. Kozminski, doi:10.1119/bfy.2015.pr.026.
An Arduino-Based Alternative to the Traditional Electronics Laboratory
We have developed a project-based alternative approach to the traditional electronics laboratory course, incorporating a hands-on sequence of guided but open-ended activities. The Arduino microprocessor is incorporated from the beginning, which allows greatly enhanced scope and flexibility for projects and increases student motivation and agency. The course is designed for junior physics majors without significant experience in circuit design and construction. Students are given an orientation to the Arduino in the second week, and almost immediately begin constructing usable devices. As the projects grow more complex during the course, students are gradually introduced to the usual range of electronic components. The Arduino is particularly suited to measurement and control processes that are common in research environments, and the project themes emphasize signal production, detection, and analysis, including logging, filtering, and amplifying. By using the Arduino to control special-purpose ICs, students learn to read and interpret a datasheet. The course has now run once, with good learning outcomes and very positive student evaluations.
R. B. Yoder, An Arduino-Based Alternative to the Traditional Electronics Laboratory, 2015 BFY Proceedings [College Park, MD, July 22-24, 2015], edited by M. Eblen-Zayas, E. Behringer, and J. Kozminski, doi:10.1119/bfy.2015.pr.027.
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