Friday, March 30, 2012

9:00 - 5:00

Workshop W1
"Mini Modeling"
   Carl Wenning -- Physics Department, Illinois State University
Loomis 232

Designed primarily for high school physics teachers, this workshop will provide a short but meaningful introduction to the Modeling Method of Instruction. Participants will discover Newton's second law of motion using a "jigsaw" approach.

Activities will be conducted to find acceleration as a function of mass and as a function of force using controlled experiments. Vernier's Graphical Analysis will be employed, and whiteboarding will take place. Learn more about Modeling now, and plan to attend one or two free Modeling workshops at Illinois State University this coming June. Workshop limited to 12 participants.

Workshop W2 has been cancelled.

Workshop W3
"Using Clickers to Engage Students in Class"
Mayla Sanchez -- Regional Technology Specialist, i>clicker
Loomis 204

Have you ever thought about using clickers in your course? i>clicker is a classroom response system that can help enrich a lecture by increasing student interaction and allowing instructors to get real-time feedback from students. Thousands of instructors across the country have adopted this technology, and have found positive results!

Join us for a hands-on demonstration of i>clickers. During this session, you'll have a first-hand experience of using i>clickers and you'll also have an opportunity to sign up for a free two-week trial! See how i>clickers might work for you and get your questions answered!

Workshop W4
"Entrepreneurial Science" - Cracker Barrel Discussion
Dan Holland -- Physics Department, Illinois State University
Loomis 264

The quantitative and critical reasoning skills obtained from studying physics has often been touted as an excellent base for success in a wide variety of fields. Additionally, studies by the Kaufmann Foundation have shown that the majority of new business ventures are started by people that do NOT have a business degree. Since a significant number of new businesses fail in the first few years, the question then becomes what information may we supply new entrepreneurs (physicists in particular) to improve their prospects of success.

At Illinois State University, we are proposing a new general education course entitled, "The Entrepreneurial Mindset". In the course we break down entrepreneurial thinking in terms of processes and give the students opportunities for experiential learning.

12:00 - 1:00

Session A - Chair: Katie Crimmins
Faculty Presentations
Loomis 151

Session B - Chair: Tom Carter
Student Research Symposium
Loomis 141

This session starts at 1:45
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The objective is to test competing models of how electromagnetism works in a rotating coordinate system. The basic question: whether or not a rotating charged solenoid will produce a potential difference on concentric capacitors located inside or outside the solenoid. Using computer simulation software we will calculate the expected induced radial electric field predicted by the competing models. We intend to detect these fields by looking for a potential difference across the capacitors. They will be connected with wire while the solenoid is rotating at a set angular velocity. The connection is broken before bringing the solenoid to rest, and a high impedance voltmeter is used to measure any potential difference. Our hope is to distinguish between the competing theories and determine which best explains the observed results. In this talk I will present the results of our simulations.

We seek to design and carry out an experiment that will distinguish between three competing theoretical models of how electromagnetism behaves in a rotating coordinate system. In particular, we look for the possibility that a powered, rotating solenoid will induce a radial electric field in the lab frame. The standard model prediction is there will be no radial electric field when rotating a solenoid. The rotating flux model predicts the maximum radial electric field to be induced inside the solenoid. The third model invokes relativistic effects from differences in velocities of the electrons and ions in the solenoid. This model predicts charge build up on the wire of a rotating solenoid producing a radial electric field of greatest magnitude outside the solenoid. In this talk I will discuss the quantitative predictions from these models, as well as the proposed experimental design.

↓

For many years, applying microscopy with focused light meant that details smaller than half the wavelength of light (200 nm) could not be resolved. Today, it is known that using conventional optics it is possible to image at least fluorescent samples with a level of detail far below the diffraction limit. Stimulated Emission Depletion (STED) microscopy and newer far-field optical approaches can provide resolutions better than 20 nm, and in principle are able to resolve molecular detail. While the diffraction barrier has motivated the invention of electron, scanning probe, and x-ray microscopy, in the life sciences 80% of all microscopy studies are still performed with lens-based (fluorescence) microscopy. In this presentation, I will discuss novel physical concept of STED, which radically breaks the diffraction barrier in focused fluorescence microscopy. The strategy in this concept exploits selected molecular transitions of the fluorescent marker to neutralize the limiting role of diffraction.

1:45

Electron impact dissociative ionization of molecules is a useful method in exploring the structure of molecules and their interaction with electrons. An economic electron gun is constructed in our lab to provide an electron beam source needed in the experiment. The electrons are generated from a heated tungsten filament in a high vacuum. They are accelerated to a few hundreds of electron volts. The electron beam is pulsed with a duration of about 100 ns. It is focused to the molecular target by an ion optical system. The trajectory of the electrons is simulated by a commercial software. The electron gun has been used in our lab to impact and ionize atoms and molecules, and the resulted mass spectra have been measured.

Interaction of light with two-level atoms is well understood through the phenomena of absorption, spontaneous emission, and stimulated emission of light. However, real atoms always have more than two levels and this multi-level structure can be exploited for variety of interesting applications. In general, interaction of light with multi-level atoms generates interference effects that are commonly termed as atomic coherent effects, for example coherent population trapping and electromagnetically induced transparency. Through these atomic coherent effects one has a controllable handle on the response of an atomic medium to the light fields that are incident on it. In this presentation I will present the interaction of three level atoms with two light fields and how it can cause emergence of structures smaller than the wavelength of both the light fields that the atom is interacting with. These ideas are applicable to atom localization, nano-lithography, and microscopy beyond the Rayleigh limit.

2:00

An introductory diffraction lab will be presented. This lab delves into the search for an understanding of the structure of DNA. The history surrounding the discovery of the double helix structure will be presented. A model representing the helical structure in a diffraction experiment will be demonstrated. This introductory lab is appropriate for life science students to experiment with practical applications of optical diffraction showing x-ray crystal diffraction. It will engage the student with the important result that it explains the discovery and measurement of the structure of DNA.

We carried out Pb²⁺ fluorescence measurements in lead borate glasses and studied the effect of adding Ag into the base glass. Lead borate glasses containing Ag (0, 1, 2 and 3 mol%) were prepared by the usual melt quench method. The prepared glasses were then annealed near the glass transition temperature (400^oC) at 5, 10, and 20 h. Fluorescence spectra of all these samples were obtained using different excitation wavelengths. In general, Pb²⁺ monomers are expected to have emission at wavelength less than 400 nm. However, no emission in this region was observed due to the base glass absorption. The emission observed at 450 nm is attributed to ³P₁ → ¹S₀ transition of Pb²⁺ ions in dimer centers. Addition of Ag enhances the Pb²⁺ luminescence intensity at 450 nm which also shows an increase with the annealing time. The possible mechanisms for the fluorescence enhancement in the present glass could be the energy transfer from isolated Ag particles and local field effects due to the difference between the dielectric functions of the glass matrix and the silver particles.

2:15

Many physics majors take an advanced laboratory course intended as an introduction to modern experimental physics. Few realize how problematic this course has become in the current curriculum. To address this issue, an organization of lab instructors has been formed to address the basic rationale and role of the course, serve as a mutual-aid society, and promote the importance of this course in the undergraduate curriculum. The Advanced Laboratory Physics Association (ALPhA) will sponsor a summer meeting to address a range of issues (jointly with APS, AAPT, and others). Audience members will be asked about the value of their own advanced lab experience.

Fluorescence properties of Eu³⁺ doped lead borate glasses containing either silver or zinc selenide nanoparticles (NPs) were investigated. Lead borate glasses containing Ag (0 and 3 mol%) and ZnSe (0 and 3 mol%) were prepared by the usual melt quench method. The prepared glasses were then annealed near the glass transition temperature (400^oC) at 5, 10, and 20 h. The effect of nanoparticles can be clearly seen on the Eu³⁺ fluorescence transitions in the range from 570 to 720 nm. Electric-dipole and magnetic-dipole transitions that originate from the Eu³⁺ level ⁵D₀ → ⁷F₂ and ⁵D₀ → ⁷F₁ respectively, exhibit changes in fluorescence intensity due to the presence of NPs. The possible mechanisms for the fluorescence enhancement in the present glass could be the energy transfer from isolated NPs and due to the changes in the structural environment of the Eu³⁺ ion induced by the presence of the NPs.
 

Break - Refreshments - Loomis Foyer
 

Welcome - Prof. S. Lance Cooper, Associate Head for Graduate Programs, Department of Physics - Loomis 151
 

"Engage to Excel: Opportunities and risks of the national initiative
 to improve STEM education"
Tim Stelzer
University of Illinois at Urbana-Champaign
Loomis 151

In February the President's Council of Advisors on Science and Technology wrote a report to the president titled: "Engage to Excel: Producing one million additional college graduates with degrees in science, technology, engineering and mathematics." This talk will briefly review the recommendations of this report, as well as some of the steps we have taken at the University of Illinois to provide transformative and sustainable change in STEM education.
 

"Interactive Online Labs: Hands-on activities exactly when you need them"
Mats Selen
University of Illinois at Urbana-Champaign
Loomis 151

Labs can play an important role in introductory physics classes, however they can also present serious pedagogical and administrative challenges. Are students experiencing the hands-on activities when they need it most? Is group-work the best approach for all experiments? How can we deal with increasing class sizes and dwindling budgets without diminishing the lab experience?

In this talk I will describe and demonstrate the innovative new Interactive Online Laboratory system being developed by members of the Physics Education Research Group at the University of Illinois. This system will allow individual students to perform sophisticated hands-on activities anywhere they have access to a computer, using inexpensive wireless data acquisition hardware that they own themselves, guided by an online learning framework that delivers content, displays and analyses data, and assesses performance.
 

Session C - Chair: Noah Schroeder
Faculty Presentations
Loomis 151

Session D - Chair: Noella D'Cruz
Student Research Symposium
Loomis 141

Many physics faculty are starting to use screencasts to assess homework and lab reports from their students. The screencasts are recorded by students who are required to explain each step of the assigned work. The mechanisms for assigning screencasts, recording them and using them as a tool for assessment will be discussed in this presentation. I will also discuss the successes and challenges I've faced with implementing screencasting into my introductory physics class this semester.

Recent work suggests that collisional ionization in rare gas atoms is primarily a two-step process in which the outer electron is first promoted to an excited state and then subsequently ionized. This presentation describes theoretical work currently being done to examine excited states in argon atoms. Of particular interest is the effect of nearby ions on excited state energies. A numerical Schroedinger equation solver is used to calculate these energies. This program uses the finite-difference time-domain method to approximate Schrodinger equation solutions for an arbitrary potential shape. In this case, a psuedopotential is used to simulate the lower 17 electrons in an argon atom while a nearby ion is simulated by the Coulomb potential from a point charge. This work aims to determine the validity of the gaseous atomic excited states in a cluster environment and is a first step in understanding important quantum mechanical effects in laser-cluster interactions.

This past year I taught a 1 credit hour seminar course for Honors students at WIU, which I called "Seeing the Invisible." This course grew out of my experiences in helping teach our capstone science education course. I structured the course around a simple question: How can we obtain reliable knowledge about things we can't see? The corollary question is: Why do we need to worry about invisible things? I drew on literary sources, as well as science and popular literature, and built each class around demonstrations or experiments that explored "invisible" phenomena such as Brownian motion, high speed motion, sound, gravitation, cosmic radiation, infrared radiation, etc. I'll present a few of lecture topics, some of the readings and some of the student responses to the class. I'll also try to draw some conclusions about the need for such a course, not just for honors students or teacher ed students, but also for physics majors.

Electronic speckle pattern interferometry, or ESPI, is a method for rapid quantification of surface motion with sub-micron resolution which is applicable to any opaque rough surface. This type of testing has proven beneficial in many industries as a quality assurance test, particularly in the fields of aerospace and automotive engineering. In the current work involving thermal expansion of a surface, the surface motion was primarily in-plane, but occurred in two dimensions. Consequently, ESPI in two dimensions was developed to evaluate the sample. To analyze this thermal expansion, a pre-existing one dimensional ESPI system was modified to simultaneously evaluate motion in both vertical and horizontal directions through polarization multiplexing. The result was an adaptable interface that allowed the user to quantify two-dimensional in-plane deformation with ten-nanometer scale resolution. These results from a particular controlled sample will be presented.

The Physics of Theatre Project was started in 2003 with the primary goal of helping theatre technicians utilize basic physics concepts in scenery design and construction. One of the outcomes of the project has been a textbook and accompanying course, taught for the first time in complete form this year at Millikin University. The course was taught in a truly interdisciplinary way, using faculty, equipment, and facilities from both Physics and Theatre departments, and focused on the direct application of physics concepts to theatrical scenarios. The final "exam" for the course required the students to design a series of scenarios based on realistic theatrical situations, such as motor-driven systems, rigging, and turntables, and then perform the necessary calculations to analyze the scenarios for practicality and equipment needs. Outcomes of the course as well as impacts on future coursework will be discussed.

In recent years, a large amount of research has been devoted to understanding the optical characteristics of composite systems consisting of a host material and nanoparticles of a different material. In particular, nonlinear optical processes, which become manifest in the presence of intense laser irradiation, often produce startling effects that are enhanced by the addition of metallic nanoparticles. Here, we present measurements of the thermally-induced change in the refractive index of a silver nanoparticle/castor oil system at various particle concentrations. The samples were prepared via laser ablation, and the refractive index change was measured using a closed-aperture, pump/probe scanning technique known as "x-scan". The results of this study and others like it may have important applications in the development of photonics devices.

Working with Jason Hwang, a graduate student at Northwestern University, we built upon others' lessons with Angry Birds. In this lesson, we challenge students to calculate the acceleration due to gravity, "g" in Angry Birds world. We use this as an intermediate lesson on the way to computational thinking exercises such as programming physics simulations.

Faraday rotation describes the rotation of the plane of polarization of light traversing a medium immersed in an external magnetic field. These rotations are very small for most materials, and accurate measurements of these rotations for materials a few centimeters in length can be quite difficult. Through the use of a lock-in amplifier these values can be measured quite accurately, even in the presence of large amounts of noise. Using an experimental apparatus employing a lock-in amplifier we took measurements for materials with well known Verdet constants to test the accuracy of our experimental technique. These measurements proved to be quite accurate when compared with published data. Currently we are using this apparatus to investigate Faraday rotation in nanoparticle composite samples, specifically CoAg nanoparticles and Ag nanoparticles in castor oil. The effective length of these samples is on the order of 100 nm making Faraday rotation much harder to detect.

Well-executed up-front design is extremely important for the efficient operation of any observatory. Preparing an observatory must take into account the local environment and atmospheric conditions, which may have a considerable effect on the necessary design and operation of the telescope. Without taking these conditions into consideration and making sure they are properly negated, images are often too dim or out of focus to use, and spectroscopic data may appear shifted and/or filtered. We describe the design and components that have been chosen for Southern Illinois University - Edwardsville's new observatory and the reason for selecting them. In addition, we explain the timeline of construction, with a focus on the integration of systems necessary to make the observatory operate smoothly and allow for much more efficient data acquisition. Finally, we investigate future plans to automate data collection systems for more accurate data runs.
 

"The Large Hadron Collider" - Probing the Universe at the biggest science project ever
Tony Liss
University of Illinois at Urbana-Champaign
Third floor Levis Faculty Center

The Large Hadron Collider, in Geneva, Switzerland took more than 10 years to build and hosts more than 5000 physicists trying to understand the tiniest building blocks of the Universe. I'll review what we know and what we don't know about how the Universe works and give an up-to-the-minute status report of searches for missing pieces like the Higgs boson and dark matter.

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