April 16-17, 2010



Spring 2010 Joint Meeting, Elon, NC

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SPS Meeting Program

Friday, April 16th, 2010

5:00 pm (Center for the Arts): Registration Begins
6:00 pm - 7:30 pm (Center for the Arts - Isabella Cannon Room): Reception/Banquet
8:00 pm - 9:00 pm (Whitley Auditorium): Keyonote lecture by Dr. Wolfgang Ketterle: Superfluid gases near absolute zero temperature
9:30 pm - 10:30 pm: ice cream social (Outside of Whitley Auditorium)

Saturday, April 17th 2010 (in Koury Business Center)

8:00 am - 9:00 am: Set up posters and breakfast
9:15 am - 10:15 am: Q&A with Dr. Ketterle (Room 101)
10:30 am - 11:00 am: AM Poster Session and Coffee Break
11:00 am - 12:00 pm: Graduate School panel (Room 346)
12:00 pm - 1:00 pm: Lunch
1:00 pm - 2:00 pm: Physics Jobs panel (Room 101)
2:00 pm - 2:30 pm: social activity (Room 101)
2:30 pm - 3pm: PM Poster Session and Tea Break, Earth-Moon-Earth test from Arecibo Observatory
3:00 pm - 5pm: Nuclear Energy Workshop and Discussions, Led by Dr. Leo Piilonen, Virginia Tech (Room 101)

Session Information and Abstracts

Friday 8:00 pm - 9:00 pm: Keyonote Lecture by Dr. Wolfgang Ketterle
MIT, 2001 Nobel Laureate
Superfluid gases near absolute zero temperature

Abstract: What is the benefit of realizing superfluidity in a gas a million times more dilute than air? Such systems consist of well-separated atoms which can be observed and manipulated with the control and precision of atomic physics, and which can be treated with first-principles calculations. One such form of superfluidity occurs when a gas of bosons undergoes Bose-Einstein condensation (BEC). A richer situation is realized with ultracold fermions. Fermions have to form pairs before they can become superfluid. By continuously changing the interaction strength using a scattering resonance we were able to study superfluidity for varying pair size, connecting the BEC limit with the case of BCS Cooper pairs, which are larger than the interatomic spacing. These studies illustrate a new approach to condensed-matter physics where many-body Hamiltonians are realized in dilute atomic gases.

Saturday 9:15 am - 10:15 am: Q&A with Dr. Ketterle (Room 101)

Saturday 11:00 am - 12:00 pm: Graduate School panel (Room 346)

Current graduate students discuss their expereince and answer questions from the audience.
John Leacock (V-Tech)
, Inna McGowin and Jason Bates (Wake Forest University), Briana Fiser (UNC-CH), Jonathan Gaffney (NCSU)

Saturday 1:00 pm - 2:30 pm: Physics Jobs panel (Room 101)

Not all physics students end up as physics professors. In fact, most former physics students work in industry, for the government, in private business, etc. What are some of the opportunities for physics grads? In this panel several former physics students discuss their paths to professional careers outside of academics. Panelists include professionals in education (Mark Hartman), network computing (Eccles Wall), navy's nuclear program (Lt. Christine Fletcher), and business (tba).

Saturday 3:00 pm - 5pm: Nuclear Energy Workshop and Discussions (Room 101)
Led by Dr. Leo Piilonen, Virginia Tech

How does nuclear energy work? Why is it perceived so poorly? And what actually is likely to occur if something goes wrong with a nuclear reactor? These questions will be addressed in the session, followed by the audience splitting up into "working groups" to explore specific issues related to nuclear energy. Finally, the "working groups" bring their ideas back to the entire audience, with discussion to follow.

AM Poster Session
Astronomy, Experimental / Theoretical Physics
Saturday, 10:30 am – 11:00 am

Simulating Exoplanets and Radial Velocity Curves
Mark Montazer (High Point University)

The most prolific method for detecting exoplanets is the radial velocity method. As discoveries are published, they are generally accompanied by data, a set of orbital parameters, and a statistical justification of the conclusions. Using both Keplerian mechanics and Newtonian mechanics, this project used Easy Java Simulations (EJS) to recreate numerous published planetary systems with a nearly identical level of statistical accuracy.

Investigating the Orbits of Asteroids with the HORIZONS Database
Matthew Marcum, Anthony Crider (Elon University)

The HORIZONS database was designed by NASA to allow users to calculate the locations of Solar System objects. We used it to generate where and when asteroids orbited in space. The PROMPT telescope array was then used to take pictures of specific asteroids as they made close approaches to Earth. Using computer software, positional coordinates were assigned to the asteroids in the pictures. These positions were then compared with the original data from HORIZONS to judge the accuracy of the telescopes. A computer program was then designed that modeled HORIZONS. The program was tested against HORIZONS for the asteroid Apophis.

Eclipse Light Curves of U Geminorum
Chelsea M. Grandy, Raya I. Cooper, and Donald F. Collins (Warren Wilson College)

U Geminorum is a dwarf nova type cataclysmic variable star that consists of a white dwarf star and a cool main sequence star. The dominant source of radiation is the hot region between these stars in an accretion disk. The high orbital inclination of the system produces a partial eclipse every cycle (approx 4.3 hr). With time series observations, obtained with a CCD camera and 20 cm telescope, we observed details in the structure and morphology of the U Geminorum system. We also observed significant daily changes in the light curves.

Emission and Reflection Nebulae
Raya I. Cooper, Chelsea M. Grandy, and Donald F. Collins (Warren Wilson College)

We photographed emission and reflection nebulae though broad-spectrum visible light filters and through a narrow band hydrogen alpha filter using a telescope and CCD camera. For each filter we measured nebula brightness relative to a nearby star’s brightness by means of image profiling. Because much of the emission consists of the hydrogen alpha line induced by UV from a nearby star, we observed that emission nebulae appear bright using a hydrogen alpha filter. Broad-spectrum starlight is strongly attenuated through the narrow band filter. Reflection nebulae merely reflect the starlight from nearby stars and do not emit in hydrogen alpha.

Fabrication of High Performance Organic Thin-Film Transistors by Spray Deposition
Natalia Azarova (Wake Forest University), Jack Owen (Wake Forest University), Marsha A. Grimminger (University of Kentucky), Eric Chapman (Wake Forest University), John E. Anthony (University of Kentucky), and Oana D. Jurchescu (Wake Forest University)

We report on spray deposition, an innovative coating technique for organic thin film transistors fabrication. Factors affecting spray deposition include pressure, gas-to-solution ratio, spray distance, solution concentration and spray time. Our devices show good homogeneity, with the best mobilities of 0.2 cm2/Vs, and on/off ratios of 10^7. This performance is comparable to that of our best spin-coated devices, while offering additional advantages such as direct scalability with large area applications. Our results demonstrate the viability of the spray approach, and open new routes to low-cost fabrication of organic electronic devices.

Nanofabrication of Elastic Magnetic Structures
Daniel Glass (Elon University)

Magnetic microspheres are used in a wide variety of applications within the scientific community – they are useful, for example, in exerting localized forces and torques at the microscale, and for binding and transporting specific molecules in a controlled manner. There is therefore demand for a wide variety of magnetic microspheres of varying size and chemical functionality. Unfortunately, current manufacturing processes are not able to produce such microspheres within a key size range. We believe we might be able to fill this gap by producing microspheres of a novel material which is a complex of magnetic nanoparticles within a crosslinked polymer matrix, a ferroelastomer.

A Classical Force Exchange Simulation
Colin McGuire (High Point University)

A classical force exchange refers to two objects that exchange a massive particle at constant speed. When the particle is "thrown" or "caught" by each object, it exerts an impulse on the object. As a result of this exchange, the objects accelerate away from each other with an apparent repulsive force. A simulation of the system was developed using Easy Java Simulations (EJS) in order to determine the distance dependence of this force as well as its dependence on other system variables. In this poster, the repulsive force, potential energy, kinetic energy, and total energy of the system will be presented.

High-Speed Video Analysis of a Cantilever
Daniel Short (High Point University)

A cantilever is a beam that is fixed at one end and free to oscillate on the other end. It is used in an atomic force microscope and a computer hard drive, for example. In this experiment, a cantilever was set up using a long, flat metal beam, and its motion was captured at 1200 fps using high-speed video. The video was analyzed to determine how the frequency of oscillation depends on the length of the beam. In addition, the video was studied to determine the relative contribution of different modes of oscillation to the equation of motion of the beam. In this poster, the high-speed video, the differential equation and solution for the cantilever, and the results of the video analysis will be presented.

Electronic Response to Molecular and Structural Changes in Fluorinated Pentacene Transistors
Claire A. McLellan (Wake Forest), Daniel David (Wake Forest), Zachary Lamport (Wake Forest), Balaji Purushothaman (University of Kentucky), Eric Chapman (Wake Forest), John E. Anthony (University of Kentucky), and Oana D. Jurchescu (Wake Forest)

We report on the morphology and electrical properties of a variety of newly developed functionalized fluorinated pentacenes. The devices of interest are organic thin film transistors (OTFTs). We have fabricated the films by drop casting the organic semiconductor from a solution of chlorobenzene. We demonstrate that chemical structure, and differences in surface treatment and drying conditions greatly affect the formation of crystals, and device properties, allowing us to measure mobilities from 10-5 cm2/Vs up to 10-1 cm2/Vs. We will discuss the effect of trialkylsilyl substituents, as well as the number of Fluorine atoms on electronic properties of these materials.

High Speed Video Analysis of Force by a Bowstring on an Arrow
Brielle Spencer (High Point University)

Bows and arrows have been used for years for both hunting and recreational purposes, and over time innovations have been made to the bow to make it easier for the user. An arrow needs to have high force on it in order to accelerate to high speed, but the user must also be capable of drawing back and easily holding the string in this position. The purpose of this project was to analyze the force by a bowstring on a Mathews Solocam Bow on an arrow as it is shot. Using high-speed video analysis, the net force on the arrow was measured, and a force versus distance graph was analyzed to determine how the force varies as a function of distance while the arrow is in contact with the string. The data showed three distinct regions: (1) an initially rapid increase in the force (just after the arrow is released), (2) a nearly uniform, linear increase, and (3) a nearly constant force that acts for more than half the distance traveled before the arrow leaves the bow. This is consistent with the design of the bow that when drawn is initially difficult to pull, becomes easier to pull, and then becomes very easy to hold when fully drawn.

An Alternative Numerical Technique for Calculating the Perpendicular Component of the Net Force on an Object
Catherine Hendricks (High Point University)

According to Newton's second law, the net force on an object is equal to the time rate of change of the object's momentum. The perpendicular component of the net force on the object changes the direction of the momentum and the tangential component of the net force changes the magnitude of the momentum. For motion of an object along any curved path, a numerical technique to calculate the perpendicular component of the net force based on a best-fit circle at a point on the object's path is being investigated. This numerical technique and approximations will be discussed along with a comparison of its results with what is obtained from a numerical derivative of the momentum vector.

Accounting for Non-Constant Thrust in a Model Rocket Simulator
Elizabeth Messina (High Point University)

Model rocket simulators usually account for the thrust of the engine by assuming it is constant. However, in reality the force is not constant. The purpose of this project is to determine the thrust curves of various model rocket engines by measuring the thrust vs. time and fitting an eight-parameter function to the data. The thrust curves were used in a model rocket simulator developed with Easy Java Simulations (EJS) and results were compared with the case of constant force.

High-Speed Video Analysis of Karate Kicks
Laura Lee (High Point University)

A properly performed karate kick requires agility and balance to produce a maximum-speed kick during the largest possible range. In this project, high-speed video analysis at 300 fps was used to study three different kicks: (1) the front kick, (2) the side kick, and (3) the roundhouse kick. The front kick was found to produced the maximum speed in the shortest amount of time. In each case, the maximum speed plateaued for a brief time interval, producing an optimal range in which to strike the target. Videos, graphs, and data analysis or the three different kicks will be presented.

PM Poster Session
Physics Education Research / Pedagogy, Public Outreach
Saturday, 2:30 pm – 3:00 pm

Possibilities: A Framework for Modeling Students’ Deductive Reasoning in Physics
Jon Gaffney (North Carolina State University)

Students often make errors when trying to solve qualitative or conceptual physics problems, but the process of deduction that students use when solving physics problems has not been thoroughly studied. To better understand that reasoning, I have developed a framework, based on the "Mental Models" framework in psychology championed by P. N. Johnson-Laird. This "Possibilities Framework" allows us to interpret errors in reasoning as a failure to flesh out all of the possibilities that result from the underlying physical premises. This suggests potential interventions for student difficulties that range from overlooking potentially relevant physical quantities to actively oversimplifying the situation.

Designing and Creating VPython Tutorial Videos
Jeff Polak, Shawn Weatherford, and Ruth Chabay (North Carolina State University)

Students taking introductory physics using the Matter and Interactions (M&I) curriculum create computational models of physical systems in VPython using only fundamental physics principles and very basic computer programming concepts. Because programming experience is not a prerequisite for the course, some concepts are introduced for the first time in the laboratory activities. A series of YouTube videos was created to introduce these concepts in a new way and to serve as a resource to the students while they worked on programming activities. The design principles and production techniques that went into the creation of the videos will be presented.

The Symposium on the Horizons in Astronomy and Physics Education (SHAPE)
Alice Churukian (UNC-Chapel Hill)

For many years, the Physics and Astronomy Department at the University of North Carolina at Chapel Hill held an annual conference for high school physics (and other science) teachers from across North Carolina to provide them with an opportunity to learn about current advances in physics and applications to the classroom. While the conference died out in the 80s, it was fondly remembered by those who attended as a chance to “recharge their batteries” and network with their counterparts from across the state. At the urging of local teachers we decided to reinstate the conference, and the Symposium on the Horizons in Astronomy and Physics Education (SHAPE) was born. The outcome of our efforts and how we hope to improve them for future events will be presented. Partially supported by a grant from the North Carolina Space Grant K-12 Professional Development program.

Investigating Student and Faculty Views on Collaboration and Peer Use of Guided-Inquiry in the Science Course
Geraldine Cochran, Mel S. Sabella (North Carolina State University)

In previous talks at the national AAPT meetings, our research group has presented findings from a survey we designed to reveal student feelings about the guided inquiry approach to instruction and we have discussed our analysis of classroom videos using a rubric to characterize group interactions. To determine more precisely what faculty from the chemistry and physics department at Chicago State University (CSU) feel constitutes effective collaboration we have conducted faculty interviews. In addition, we have conducted student interviews and recorded student analysis of their own collaboration. We will present our initial findings.

Real time analysis of a mechanical oscillator driven with a continuously scanned driver frequency
Donald Maloy (UNC-Pembroke)

Considering the well-known behavior of transient effects on steady state oscillations at predetermined incremental frequencies, we set out to investigate the effect imposed by continuously variable scan rates on the behavior of a classical driven harmonic oscillator. A computer controlled soundcard drove a subwoofer with an amplified linearly ramped AC voltage. A motion sensor, Pasco interface and Data Studio software functioned as a low frequency spectrum analyzer for the oscillating air filled sphere. Precise computer based simulations using Easy Java Simulations (EJS) provided additional insight into the underlying physics of the system.

Climate Leadership and Energy Awareness Program at UNC-CH
Duane Deardorff (UNC-Chapel Hill)

The Climate Leadership and Energy Awareness Program (Climate LEAP) at the University of North Carolina at Chapel Hill engages selected high-school students in interdisciplinary, hands-on science and mathematics activities, and provides opportunities to develop science communication and leadership skills. Students participate in a one-week, non-residential summer institute at UNC and at least three, half-day Saturday academies during the academic year. Climate LEAP is made possible by a three-year grant from the Burroughs Wellcome Fund which includes providing stipends for the two cohorts of 24 students each who will participate in the program each year.

Chucking Pumpkins: A Physics Outreach Program
Aaron Summers (Elon University)

Elon’s chapter of SPS hosts an annual “Great Pumpkin Fling” in which a trebuchet, designed and constructed by the Society of Physics Students, is used to catapult pumpkins across a field. For every pumpkin flung by the contraption, a dollar donation or canned food item is requested. These proceeds go directly to Loaves and Fish, a local Alamance County charity. This event is a great way to not only raise money and food for a local charity, but also interest local children in physics, and how physics relates to our everyday surroundings.

Energy Reduction Research by Students Becomes Legislation
Xenia Brewington (Winston-Salem State University)

In April 2007 Winston-Salem State University chemistry department undergraduates presented a research poster at the UNC Research in the Capital Symposium. The subject of the poster, "Energy Reduction: Insulating Residential Hot Waterlines," caught the attention of a North Carolina Representative. He wrote this idea into House Bill 1702 which he placed on the docket the same day as the Symposium. The final Bill, "An Act to Conserve Energy," became Session Law 2007-542 in August 2007. This process illustrates how undergraduate research can really "make a difference."

Annual Regional Astronomy Meetings at GTCC
Tom English (Guilford Technical Community College)

Cline Observatory at Guilford Technical Community College sponsors two annual regional astronomy meetings that are open to physics students and faculty. In the fall (usually early October), GTCC hosts the Technical Meeting of NC Astronomers, where student and professional researchers present their work, and invited astronomers of note also present. The spring event (early March) is designed for a more general audience, drawing amateur astronomers from five states for a full day of talks and displays. Each meeting is held on a Saturday, but opens with a special evening public lecture the night before. There is no registration cost for any of the programs.