Undergraduate Physics Laboratory Research Articles

Soil analysis using a 2″ NaI gamma detector

We describe an undergraduate physics laboratory experiment that uses a 2-inch diameter NaI gamma detector to measure natural radiation in soils. Students first calibrate the detector for the source-detector geometry, energy-dependent detection efficiency, and sample self-absorption. Then, the activity of the 238U and 232Th decay series, as well as the activity of 40K in the soil, are measured. The results are comparable in accuracy to those obtained using a high-resolution germanium gamma detector.

Commercial virtual reality headsets for developing augmented reality setups to track three-dimensional motion in real time

We designed and tested a 3D motion tracking system which displays acquired and derived data using augmented reality. This setup, based on a virtual reality headset and its controllers, is a relatively low-cost, high-precision, six degrees of freedom, high-speed, multiple-objects tracking device. This apparatus proves to be a very high-quality motion sensor which can be used in the physics laboratory for motion tracking. Stereo cameras may also be attached to the headset in order to achieve augmented reality, which can be a winning addition in order to effectively use these devices in the physics laboratory. In view of its characteristics, this system can be adopted in the study of motion both at high school and undergraduate physics laboratories.

Circuit analogue of relativistic aberration of light using low-cost, low-complexity operational amplifier-based all-pass filters

We propose, simulate, and experimentally demonstrate a circuit analogue of a special relativity phenomenon known as relativistic aberration of light (RAL) by using a surprisingly simple, low-cost, and easily accessible electronic circuit-based all-pass filter. This work is useful for two audiences: (i) physicists who are interested in research on circuit analogues; and (ii) physics educators who are interested in using the research results to raise interest among students by incorporating analogue-based learning into undergraduate physics lecture and laboratory courses. For the first type of audience, we present a rigorous theoretical framework describing this RAL-on-an-electronic-chip analogy. We show by (i) analytical modelling, (ii) commercial circuit software simulation, and (iii) experiment that the electrical phase shift Φ of the output signal is analogous to the RAL angle, Ψ. This parameter opens up a path among researchers to model the effects of other relativistic phenomena with electronic circuits. For the second type of audience, we discuss the potential role of RAL-on-an-electronic-chip in physics education (both in lectures and laboratory) that combines students’ learnings of both physics and electronic circuits, at the same time. We also explore briefly its relevance to engineering education.

Conductance quantization in atomic-sized gold contacts using a low-cost mechanically controllable break junction setup

The mechanically controllable break junction (MCBJ) experimental setup is one of the main techniques employed in the study of electronic transport properties at the atomic and molecular scales. This work presents the construction of an inexpensive and simple but robust setup that shows the emergence of conductance quantization as a macroscopic gold wire is pulled to atomic dimensions. The homemade device is based on the MCBJ principle and allows repeatedly forming and breaking the metallic contact to perform a statistical analysis of the data extracting the most frequent electron transport structure. The histogram built from conductance measurements, at room temperature in air, show that the quality of the MCBJ equipment developed here is comparable to that of more sophisticated devices used in research laboratories. It is able to resolve up to three conductance peaks associated with gold nanowires reported in the literature. Such an experiment is suggested to be implemented as a powerful pedagogical tool in modern undergraduate physics labs.

Epistemology, socialization, help seeking, and gender-based views in in-person and online, hands-on undergraduate physics laboratories

Undergraduate physics laboratory course structures have been identified in policy reports for novel design innovations to meet the needs of a diverse and growing student population. To this end, an online, hands-on laboratory option was implemented at a large, public university for introductory physics students using the iOLab device. To determine whether students in this new course structure had similar perspectives to their in-person counterparts in terms of select attitudinal measures, a quasiexperimental, observational quantitative study was undertaken to measure students’ epistemological views as well as their beliefs about socialization and help seeking in online and in-person laboratory environments. Undergraduate students who were enrolled in calculus-based introductory physics (N=998) were surveyed in the second half of the semester to elicit their epistemological beliefs about physics laboratory work and their views on social engagement and academic help seeking in the laboratory. Parametric and nonparametric comparisons of central tendency were employed to measure differences between students in the in-person and online laboratories, as well as gender differences and associated interaction effects. Students showed no overall differences in attitudes related to epistemological and help seeking beliefs. There were significant differences related to views of socialization; students taking in-person physics laboratories valued socialization more than students taking the course online. Gender differences in epistemological and help seeking beliefs were identified overall, however, these differences were no longer significant when examining the interactions of laboratory type and gender. This finding suggests that self-selection into laboratory type may diminish gender gaps in affective domains by allowing students to choose the laboratory structure that meets their learning and logistical needs. In terms of physics epistemology, socialization and help seeking in the laboratory may not be as important to students’ perceptions of physics knowledge acquisition as previously thought. This study provides insights into the feasibility of online, hands-on laboratory experiences to meet the affective goals articulated in in-person laboratories, as well as institutional recommendations for advising students to select courses that match their individual learning styles.Received 23 February 2020Accepted 15 July 2020DOI:https://doi.org/10.1103/PhysRevPhysEducRes.16.020116Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasDiversity & inclusionEpistemology, attitudes, & beliefsLearning environmentPhysics Education Research

Visualization of Acoustic Standing Waves in a Closed Pipe Based on an Electronic Speckle Pattern Interferometer

We visualize acoustic standing waves supported in a closed-end square pipe based on an electronic speckle pattern interferometer and measure the wavelengths of the acoustic standing waves for undergraduate physics lab courses. Generating four acoustic standing waves of frequencies below the cutoff frequency governed by the physical dimensions of the pipe, we obtain the distribution of the irradiance difference of the speckle patterns in the interferogram and compare that to the result of a theoretical calculation. In addition, we estimate the wavelengths of the acoustic standing waves by measuring the distances between adjacent nodes of the speckle patterns. We show that the experimental results and the results of the theoretical calculations are in good agreement. This work facilitates the understanding of electronic speckle pattern interferometers and their applications in visualizations of acoustic waves for undergraduate physics laboratories.

Understanding the effect of rolling friction in the inclined track experiment

In general, undergraduate experimental physics laboratories do not usually have experiments designed to address rolling friction and to measure the value of the rolling friction coefficient. This work explores an experiment, which has the potential to arouse students’ curiosity about rolling friction by addressing a counterintuitive aspect of the behavior of a sphere that rolls up, stops and then rolls down on an inclined track. In fact, due to the difference in the net static friction in the upward and downward movements caused by the rolling friction term, the sphere’s acceleration when rolling upward is higher than when rolling downward. This difference, which had been predicted theoretically, was easily demonstrated graphically by video analysis, using both rubber and mouse balls. For two steel balls, this difference was more subtle, but it was still possible to detect it numerically. The experimental setup employed typical laboratory equipment and the free video analysis software Tracker to collect position and velocity data. The rolling friction coefficient was calculated with good precision by means of an angular coefficient of a fitted first-degree function involving appropriate variables.

Digital recording and optical reconstruction of holograms on transparent film

This article analytically and experimentally provides the principle of hologram construction and reconstruction using a single thin-lens system. Instead of recording on a holographic film, the interference pattern between the reference beam and the object beam is digitally recorded in an image file using CCD camera and the real hologram is printed on a transparent film (overhead projector film). Finally, the real images of the object are then experimentally reconstructed by an optical system. Moreover, the numerical analysis involved in the hologram reconstruction is also presented in order to compare with the practical result. The methods of hologram construction on the transparent film and optical reconstruction are worked out here in detail. By avoiding chemical processes, we may save time and reduce any cost incurred. This experiment can readily be performed in an undergraduate physics laboratory.

Exploring the cantilever: teaching tools for atomic force microscopy

This paper presents a series of experiments that aim to aid with the understanding of some of the fundamental concepts pertaining to the resonance of cantilevers. The goal is to provide an accessible platform for exploring how the cantilever, one of the fundamental components in non-contact scanning probe/atomic force microscopy, is utilized in measuring forces. A straightforward experiment that utilizes a piezo buzzer and oscilloscope to measure the natural resonance frequency of a cantilever is showcased. This information is used to demonstrate how the frequency is related to the length and to extract information about the Young’s modulus of the material. It also presents how one is able to utilize a piezo-driven craft stick to measure masses within a 100th of a gram. Utilizing the same driven craft sticks, are a series of experiments exhibited that employ the use of a magnetic probe to explore the differences between attractive and repulsive forces. In addition, a discussion of how these results relate to the tip-sample interactions in atomic force microscopy will be displayed. The experiments presented were developed as part of an undergraduate modern physics laboratory and a scanning probe microscopy course. A review of how these experiments were implemented in these courses will be presented. The experiments highlighted in this manuscript were employed as part of a distance learning kit for a modern laboratory, that was converted to an e-learning classroom due to social distancing restrictions. A description of the kits utilized will be provided.

Design, construction and utilization of a university plasma laboratory

We present the elements required to construct two devices used in an undergraduate plasma physics laboratory. The materials and construction costs of the sources, the vacuum systems and probe drives and electrical circuits are presented in detail in the text and the first appendix. We also provide the software for probe motion and data acquisition as well as the electrical schematics for key components. Experiments which have been performed are listed and two (resonance cones and whistler waves) are described in greater detail. The machines are flexible and original research is possible.

Alternative approaches in digital era to handle undergraduate physics (mechanics) laboratory: a case study of moment of inertia of a flywheel experiment

With the invasion of Digital Era on all activities of life, alternative approaches are emerging to explore a single situation in many ways, offering new opportunities and insights about learning behaviour of the student. It is expected that this is going to impact traditional laboratory practices in different ways. The moot question is: can these alternative explorations be used for enhancing learning experiences of the learners, make laboratory a more engaging place and tuning learners’ alternative conceptions with the conceptions of an expert. In this case study, we present three ways to perform an experiment to calculate the moment of inertia of a flywheel in a typical undergraduate Mechanics (Physics) laboratory: (i) the traditional way using a stopwatch and a meter rod as basic measuring tools, (ii) by using a video analyser of a typical setup of the experiment and (iii) a modelling software available in a web-based virtual laboratory. The physics education research strategies are applied to observe the pedagogical value of performing the same experiment in three ways together. To go ahead with this approach, implemented through pre-post-test methodology, a concept inventory has been devised to identify the alternative conceptions around the moment of inertia, theorems of the moment of inertia and flywheel as a mechanical device to control rotational motion in a daily life. An effort has been made to address the alternative conceptions during the performance of the same experiment in three distinct ways. Finally, a perception survey was also carried out to know about this multi-representational approach’s (a) pedagogical effectiveness, (b) effect on laboratory climate, (c) expectations of students, (d) laboratory engagement and (e) instructor-student relationship.

Action Research: Using a 5E Instructional Approach to Improve Undergraduate Physics Laboratory Instruction

Action Research: Using a 5E Instructional Approach to Improve Undergraduate Physics Laboratory Instruction

Emerging and Persistent Issues in the Delivery of Asynchronous Non-Traditional Undergraduate Physics Experiments

Remote physics laboratory activities are common tools of use in physics in traditional, online, and distance education to enhance student learning. Although these offerings necessitated by technological advances, spur innovation and improvement in undergraduate physics education, their use as stand-alone substitutes for instructor-guided physical laboratory experiments remain the center of debate and research. This paper discusses the effectiveness of the current pedagogic issues in the delivery and learning of four different types of remote introductory undergraduate physics laboratory activities, the breakthroughs, and the areas that require further investigations. The instructional issues include experiment preparation and design, student engagement, guidance, and safety. This review noted the positive impacts of stand-alone remote physics lab activities on mostly undergraduate non-physics majors, partly due to the limited number of institutions currently conferring complete online/distance physics degrees worldwide. We recommend further studies on the effect on physics students who end up in experimental physics-related careers.

Experiments and models about the force between permanent magnets: asymptotic analysis of a difficult problem

We propose a simple experiment, which allows students to explore quantitatively the magnetic interaction between neodymium cylindrical magnets. The experiment employs a precision digital balance, two screws with known thread pitch and two transparent tubes to measure the repulsive force between two magnets as a function of their distance. Different measurements are performed, focusing on the behavior of the interaction force at short and long distances and the role of the magnets’ aspect ratio. We discuss the comparison between theoretical expectations resulting from conceptually simple approximate models and experimental results. The experiments employ inexpensive materials and address a relevant topic in the physics curriculum. Thus, they are appropriate for the undergraduate physics laboratory, for advanced high school students, and in the context of teacher education and in-service training to enhance students’ knowledge of magnetism.

Light interference pattern measurements from automated low-cost Young’s double-slit experiments

Young’s double-slit experiment is commonly used in undergraduate physics laboratory to show the wave nature of light. As an alternative to expensive commercial kits, here we present an automated, low–cost light intensity measurement setup that allows real-time visualization of the interference pattern. The light intensity is measured by a light dependent resistor placed on the head of a dot matrix printer. The head motion is controlled by an Arduino which also collects the data and send them to a computer. The interference pattern obtained by the setup is in agreement with a model that includes the degree of the coherence of the light source and the effective size related to the light collecting area of the resistor. The apparatus allows quantitative data analysis from the measured light patterns and is suitable to be used in undergraduate physics laboratories.

Single-pixel camera

A single-pixel camera is an interesting alternative to modern digital cameras featuring millions of pixels. A single-pixel camera is a method that produces images by exploring the object features with a series of spatially resolved patterns of light field while measuring the correlated intensity on a single detector. Nowadays, single-pixel cameras are used on those applications where multi-pixel detectors are not available because the wavelength is not in visible range or light intensity is extremely low. The spatial light modulator is an essential part of any single-pixel camera systems. They are, unfortunately, very expensive. We describe a low-cost version of single pixel camera that can be used in undergraduate physics laboratories. We show that with this camera setup students can easily demonstrate basic characteristics of computational ghost imaging and traditional raster and basis scan. Finally, we explain how to perform compressive sampling of images where the number of measurements is well below the actual pixel number. Compressive sampling is a rapidly expanding method to perform image or signal reconstructions in many field of research.

Robert A. Millikan and the Undergraduate Physics Laboratory

Ask a physics person what the name of Robert A. Millikan brings to mind, and most would immediately think of the eponymous experiments that he did with the charge on the electron in the years 1908 to 1913. A few might remember his work, starting in 1914, with the experimental determination of Planck’s constant using the photoelectric effect. Few will remember his work with bringing experiment into the education of undergraduate physics students in the early years of the 20th century. In this paper I will show how he achieved this by examining the numerous textbooks that he wrote.

Image processing for quantitative measurement of e/m in the undergraduate laboratory

In conventional e/m experiments performed in undergraduate laboratories, generally a simple mechanical ruler is used to measure the radius of the circular trajectory of the electrons. But, the measurement error in this technique is mostly big and varies from one student to another. As an alternative to a mechanical ruler, we proposed a more accurate and a more precise technique for measuring the radius. This technique is based on image processing and it is well known that the image processing is one of the more powerful techniques for precise measurements in physical experiments.ImageJ software was used for image processing and for taking photographs of the circular trajectory of the electrons in the e/m experiment. ImageJ is a java-based image processing program which was developed by the National Institute of Health of USA.The photographs of the trajectory were taken by using a generic webcam connected to the computer and it was observed that the trajectory was not visible for a one shot photograph which is due to the low intensity of the light coming from the trajectory. By taking multiple photographs of the trajectory at the same time and adding these photographs to each other, the trajectory on the photograph became visible.It was concluded that the accuracy of the measuring the radius of the circular trajectory could be increased by using the image processing and it was found that the relative error made in this measurement is about 0.5% which is 10 times smaller than the relative errors made in conventional measuring techniques performed by a simple mechanical ruler (around 5%). This result directly increases the precision and the accuracy of measuring the e/m ratio of the electrons in undergraduate physics laboratories.

Using think-aloud interviews to characterize model-based reasoning in electronics for a laboratory course assessment

Models of physical systems are used to explain and predict experimental results and observations. The Modeling Framework for Experimental Physics describes the process by which physicists revise their models to account for the newly acquired observations, or change their apparatus to better represent their models when they encounter discrepancies between actual and expected behavior of a system. While modeling is a nationally recognized learning outcome for undergraduate physics lab courses, no assessments of students' model-based reasoning exist for upper-division labs. As part of a larger effort to create two assessments of students' modeling abilities, we used the Modeling Framework to develop and code think-aloud problem-solving activities centered on investigating an inverting amplifier circuit. This study is the second phase of a multiphase assessment instrument development process. Here, we focus on characterizing the range of modeling pathways students employ while interpreting the output signal of a circuit functioning far outside its recommended operation range. We end by discussing four outcomes of this work: (1) Students engaged in all modeling subtasks, and they spent the most time making measurements, making comparisons, and enacting revisions; (2) Each subtask occurred in close temporal proximity to all over subtasks; (3) Sometimes, students propose causes that do not follow logically from observed discrepancies; (4) Similarly, students often rely on their experiential knowledge and enact revisions that do not follow logically from articulated proposed causes.

Plot Twist: Changing the Story in Graphing Skills with an Open-Ended Approach

Two of the most fundamental skills that students acquire in introductory undergraduate physics laboratory courses are how to accurately plot data and interpret the physical meaning of linear graphs. We redesigned our graphing skills lab with an open-ended approach designed to promote inquiry in graphical analysis and to address specific areas of weakness in students’ understanding of graphs. Students had to decide on their own how to graph data in order to promote understanding of linear relationships between variables and slope. Students completing the new open-ended lab developed and retained better graphing skills than students that were taught the lab with a more traditional cookbook approach.