Physics

Unpacking Grading & Assessment Practices in Upper-Division Physics (O)

Presenter: Jessica Searl
Faculty Project Advisor: David Ward

Racial and gender disparities in physics student outcomes have prompted research into a variety of possible contributing factors. There has, however, been very little research conducted examining the impact of grading and assessment methods in upper-division physics on student engagement and success. We examined the impact of different types of feedback and assessment, particularly comparing students' experience in an 'ungraded' course, a class where the assignments were not graded but were assessed with verbal feedback, versus a traditionally graded course. We conducted semi-structured interviews with four upper- division physics students about their experiences with both standard physics grading and feedback practices as well as in an ungraded course. The presentation examines the student responses and analyzes the impact of current practices.

The Long-Term Impacts of Attending a Low-Income School (O)

Presenter: Taylor Overcast
Faculty Project Advisor: David Ward

The issues with today's educational system are multifaceted. There are issues relating to ethnic segregation, socioeconomic segregation, locational issues, and many more; however, the issue of socioeconomic segregation perpetrates several common dividers — gender, ethnicity, and location. Therefore, the long-term impacts of attending a low-income school will be the focus. Specifically, the relationship of a low-income childhood and attending a 4-year institution to study a STEM field will be the focal point of the presentation. The data behind the cyclical nature of poverty, and the impact of parental education level on students' projected education completion will be studied. The additional hardships that low-income students face will be examined — lack of sleep, technology, and extracurriculars. In addition, the impacts of low-income conditions on test scores, teacher retention rates, and college attendance will be explored. Finally, the data of STEM-focused bachelor degrees achieved by low-income students will be presented.

The Simplicity of Quantum Randomness (P)

Presenter: Daniel Thomas
Faculty Advisor: Fonsie Guilaran

Random number generators are readily available online for extremely cheap, but do they produce truly random numbers? The purpose of this research was to explore randomness and ways to test for it, to build the simplest quantum random number generator (QRnG) given the resources at hand, and prove its intrinsic randomness using a logical and mathematical analysis. The components of the experiment were radioactive compounds [Ba – 133, Co – 60, Ra – 226], Geiger Tube, and a ST – 360 Radiation Counter. By collecting one batch of decay counts as a result of gamma ray detection from each of the radioactive compounds, respectively, the average of the decay values was used to assemble a logic gate. This logic gate was constructed such that when the decay count was greater than the average, a value of 1 was given, below the average, 0. This yielded a binary sequence that, according to the principles of nuclear and quantum physics, should be perfectly random. Using the defined process, three separate strands of sixty perfectly random binary values were attained. Using a mathematical analysis, the data from the aforementioned system was tested to see if it was truly random.

Measuring the Chaotic Behavior of Dripping Water (P)

Presenter: Scott Morris
Faculty Advisor: Fonsie Guilaran

The focus of this project is to measure the chaotic behavior of water droplets under various conditions and, if possible, to use these measurements to calculate the Feigenbaum bifurcation constant, δ. According to several published works, the drip rate of water does not smoothly and continuously increase over time in response to increasing pressure. Instead, the falling droplet's frequency sharply doubles over distinct intervals until the system eventually becomes chaotic. By adopting and utilizing several different experimental techniques, this research chronicles the efforts in documenting this odd, counterintuitive behavior.

Determination of Liquid Viscosity Using a Bluetooth PASCO Smart Cart (P)

Presenter: Katherine Ward
Faculty Advisor: Geoffrey Poore

The goal of this research project is to experimentally determine the resistance coefficients of viscous fluids and compare to theoretical predictions. This is done by tying a string to a Bluetooth PASCO Smart Cart, running the string over a pulley, and attaching a metal sphere to the string. The sphere is submerged in a viscous fluid, such as water, oil, or honey. When the system is released from rest, it experiences linear drag force that acts on the falling mass. The application of Stokes' Law and the data collected from the smart cart allows for a determination of the viscosity of the chosen fluid.

Simulating the Gösgen Nuclear Reactor Experiment in Search of a Sterile Neutrino (P)

Presenter: Jonathan Van Neste
Faculty Advisor: Fonsie Guilaran

Neutrinos exist in three known flavors which they can oscillate between during neutrino oscillations. A common way to study these oscillations is at nuclear reactors, where electron antineutrinos are emitted towards detectors. One such experiment was performed at the nuclear reactor in Gösgen, Switzerland. Three detectors were 37.9, 45.9, and 64.7 m from the reactor. The Gösgen experimentalists examined Χ² values, creating an exclusion region for the two oscillation parameters. The results from the Gösgen experiments, however, do not fit the standard three neutrino model. A possible new model adds a fourth neutrino, called a “sterile” neutrino. To examine this model, we constructed a computational model of the Gösgen experiments that reproduces their exclusion region. Then, by adding a routine that graphed ΔΧ², we found the four-neutrino analysis fits the data better and favors four specific values for Δm41^2 which are 100 times larger than currently accepted values for Δm_31^2

New Energy Level Structure of the Isotopes Gd-162 and Gd-164 (P)

Presenter: Christian Brown
Faculty Advisor: Geoffrey Poore

Energy levels in the isotopes ^162,164Gd were constructed via triple and quadruple coincidence Gamma-ray data from observations of the spontaneous fission of ²⁵² Cf. Gamma-rays from fission events of a 62 µCi ²⁵² Cf source were measured in the center of the Gamma-ray spectrometer Gammasphere. This produced 5.7x1011 triple or higher events and 1.9x1011 quadruple or higher events occurring within 1 µs of each other. This data set was analyzed to construct new energy level schemes for ^162,164Gd. Levels and transitions previously identified in the ground state rotational band have been confirmed. Additionally, several new transitions and levels are observed in both isotopes, including the establishment of a Gamma vibrational band from 2+ to 9+ for the first time, and the addition of a level in the ground state rotational band of ¹⁶²Gd.

Exploring the Behavior of Spring-mass Systems with the Aid of Computational Modeling (P)

Presenter: Alexandra Bodnar
Faculty Advisor: Fonsie Guilaran

If you’ve ever released a vertically hanging slinky, you may have noticed it falls in such a way that the top falls to meet the bottom before the slinky as a whole falls to the ground. That is, the bottom will remain fixed until the spring is fully compressed before the entire mass system is pulled to the ground. Hanging springs weighted with masses behave just the same. This experiment consisted of testing two weighted springs, with differing k constants, to see if both would reach the ground at the same time if simultaneously released from a) the same height with respect to the top of the springs and b) the same height with respect to the hanging mass. The goal was to provide a demonstration for faculty to utilize in a class room setting and introduce students to computational physics modeling to gain basic programming skills.

Exploring Low-Cost Planetarium Construction Techniques (P)

Presenter: Gabrielle LeBeau
Faculty Advisor: Fonsie Guilaran

There are currently more than 20 schools in Jackson, TN catering to grades K-12 with relatively little access to facilities for scientific education within a 60-mile radius. To help instill in kids a love of learning, the goal of this project was to create an engaging, immersive, and interactive educational environment. The chosen solution was to design and build a portable planetarium cheaper than those available on the market today. Over the course of six months, a fully functioning planetarium was constructed for 4.4% the cost of the cheapest one sold online. Although it was not necessarily portable, it was movable. The structure and design will hopefully be a prototype for future projects and attempts to build affordable, portable planetariums which will hopefully be marketed to elementary, junior high, and high schools in the community.

Circuits and Espionage: Can You Outsmart the Motion Sensor? (P)

Presenter: Andrew Edmiston
Faculty Advisors: Fonsie Guilaran and Ethan Wilding

Whether a person has noble goals (such as national security or human flourishing), or nefarious schemes (such as hacking or morally dubious business practices)–the time-honored process of reverse engineering is often an indispensable tool for scientific learning. The goal of this project was to reverse engineer solar- powered, motion-sensitive lights, in order to see (1) What they do, (2) How they do it, and (3) How well they do it. One of the key questions guiding this project was, “What would it take to avoid being detected by this sensor?” In other words, what are the product’s strengths and weaknesses? Experiments included circuitry analysis, voltage and current testing, measuring brightness of the lights, and testing the limits of the motion sensor. Inspiration for this project was based in large part on the work of Ken Shirriff, who used reverse engineering to analyze the design of Apple IPhone chargers.

Pendulum of Varying Length

Presenter: Dominick Jaynes
Faculty Advisor: Geoffrey Poore

The purpose of this experiment was to compare the periods of oscillation of a simple pendulum and a pendulum that varies in length during its motion. Solving for the period of the simple pendulum is a rather simple process, and varying the length of the pendulum over time makes things rather complicated. The goal was to see if there was a theoretical difference between the two periods at large amplitudes, and if that difference could be measured experimentally. The large amplitude in this case was an initial angle of sixty degrees. The simple pendulum case could be solved analytically, while the varying length pendulum has no analytic solution and required numerical analysis using Mathematica. The theory showed a difference between the two periods, and this difference was detected experimentally using the initial angle of sixty degrees, although it was not as great of a difference as the theory predicted.

Building a Lock-in Amplifier for an Ionization Experiment

Presenter: Mason Ruby
Faculty Advisor: Fonsie Guilaran

A lock-in amplifier is a device used to recover information from an electric signal with a high signal-to-noise ratio. It achieves this using phase sensitive detection in which a periodic signal is multiplied by a reference signal with the same frequency. The result is then integrated, resulting in a DC signal proportional to the original signal without any influence from the noise. Our research focused on implementing this technique in an ionization experiment utilizing time-of-flight mass spectrometry so that we could dramatically increase the range of our detector. The experiment required that we keep the waveform of the signal intact which is usually impossible with a lock-in amplifier since the output is a DC signal. We developed a method in which the phase of the reference was incrementally changed, causing the output of the lock-in to change also. Taking the derivative of the output reproduced the original waveform. Thus, we were able to show that it is possible to retrieve temporal information from a lock-in amplifier, potentially allowing us to use it for this experiment as well as any other requiring a large detection range.