Fall 2014 Physics Colloquium

More information coming soon!

Thursday, September 25th
Dr. Hans Verlinde, Department of Meteorology, Pennsylvania State University

"I've Looked at Clouds From All Sides Now"

Contrary to intuition, clouds in the cold Arctic atmosphere frequently contain liquid water, even at temperatures as low as -30 °C! The presence of liquid water in these clouds is important because it changes how much the cloud warms the surface, and thus plays a role in the winter-time formation and summer melting of ice. In order to understand the role of these clouds in the rapidly changing Arctic, we understand their physical processes, and to do so need quantitative observations of their properties. But getting these observations is difficult: if you fly a plane into one of these clouds the plane can easily transform into a ball of ice. Therefore, we have to resort to remote sensing of the cloud properties, using a variety of sensors.

He will talk about the physics of mixed-phase clouds (liquid cloud that precipitates ice) and the challenges of observing their characteristics.

Noon
Tome 115
Pizza provided

Wednesday, October 15th
Kenneth J. Davis, Professor of Meteorology, Pennsylvania State University
"The Breathing of the Earth and Fires of Industry: Measuring Greenhouse Gas Sources and Sinks at Regional Scales"

Human activity is increasing the greenhouse gas burden of the earth's atmosphere, resulting in an increasingly strong greenhouse effect. This strengthening greenhouse effect is changing the earth's climate and is highly likely to lead to increasingly severe climate changes if greenhouse gas emissions are not reduced.  In response to this challenge, efforts to reduce greenhouse gas emissions, both voluntary and regulatory, are emerging.  Measurements of emissions are needed to ensure that reduction targets are being met. Further, the earth's biosphere is an active source and sink of greenhouse gases, adding complexity to the problem of designing optimal climate management strategies.

He will review the role of greenhouse gases in the earth's climate system, the natural cycles of greenhouse gas sources and sinks, and the impact of human activity on the concentration of greenhouse gases in the earth's atmosphere. He will next review the current state of our ability to measure greenhouse gas sources and sinks using atmospheric methods. Methods include tower-based turbulent flux measurements, extrapolation of ecosystem fluxes across space using space-based remote sensing, and atmospheric budgets that utilize weather forecast systems combined with tower-, aircraft- and satellite-based greenhouse gas concentration measurements. Finally, he will present current applications of these methods to determine the net carbon dioxide fluxes of agricultural and forest landscapes, carbon dioxide and methane emissions from cities, and methane emissions from the shale gas fields of northern Pennsylvania.

12:30 p.m.
Stafford Lecture Room
Pizza provided


Thursday, October 23rd

Olivia Wilkins, Dickinson College
"Organic Chemistry in Young-Stellar Objects"

Astrochemistry is an emerging field that applies the lens of chemistry to the formation of stars, planets, atmospheres, and molecules.  Among other projects, the Ӧberg Astrochemistry Group at the Harvard-Smithsonian Center for Astrophysics (CfA) investigates the formation of complex organic molecules and unsaturated carbon chains in protostellar environments. Understanding the chemical processes associated with such molecular species has the potential to provide insight into an even more complex prebiotic chemistry. In addition to discussing the work done with Karin Ӧberg at the CfA, this talk will provide an overview of radio astronomy and the journey by which I, a chemistry student, became involved in astronomy research. 

Noon
Tome 115
Pizza provided

Tuesday, November 18th
Sigma Pi Sigma Induction Ceremony & Majors Dinner 
Keynote Speaker - Sean Finnegan '01
Program Manager, U.S. Department of Energy's Office of Science, Fusion Energy Sciences
"Powered by Fusion: The Universe, the Nation, and You?"

The process of nuclear fusion provides the energy that powers the stars, forms elements, and sustains life on Earth. From solar and wind to coal and shale-gas, nearly all sources of energy can trace their origins back to a fusion process. Over the course of the past 50 years significant progress has been made toward the development of fusion energy here on Earth, but the difficulty of the task has prevented mankind from realizing this dream. In this presentation Sean will discuss the role of fusion in powering the universe and the Earth, and in the process connect the various scientific and technological themes to the various offices within the U.S. Department of Energy. Today, the U.S. Department of Energy is the largest federal supporter of basic science research with a portfolio ranging from dark-energy to batteries, but it all started with fusion.

4:30 p.m.
Tome 115

Sigma Pi Sigma Dinner
6:00 p.m.
HUB Siderooms

Thursday, November 20th
Kim Moore, Ph.D. Candidate, Department of Physics, University of Maryland
"Using Physics as a Tool for Supporting and Enhancing our Understanding of the Life Sciences"

Over the last decade there have been increasingly urgent calls for the reform of the undergraduate science curriculum for life sciences majors and pre-medical students.1-4 In response to these concerns, the National Experiment in Undergraduate Science education (NEXUS) project was initiated to develop new science and math support courses. For the past five years, the University of Maryland's Physics Education Research Group and Biophysics Program have collaborated to design and implement an introductory physics course for life sciences (IPLS) students, employing student-centered pedagogy, a focus on epistemological development, and a revised course content emphasizing the physics relevant to living systems and the importance of interdisciplinary thinking. This calculus-based course, requiring a year of calculus, a year of biology, and a semester of chemistry as prerequisites, is aimed at using physics as a tool for supporting and enhancing students' understanding of biological phenomena, enabling a richer and more complex presentation of these phenomena in upper-level biology and chemistry courses.5

In 2012, a new laboratory curriculum was developed for and incorporated into this IPLS reform effort.6 These labs address physical issues at biological scales using microscopy, image and video analysis, electrophoresis, and spectroscopy in an open, non-protocol-driven environment centered on the question: "How can quantitative physical analyses help us understand biological phenomena?" This talk will focus on the design and implementation of these labs, their function within the larger NEXUS/Physics curriculum, and an analysis of the student response to this new approach.

[This work is supported by funding from the NSF and HHMI. Information about the NEXUS/Physics project can be found at www.nexusphysics.umd.edu.]

[1] National Research Council, Bio 2010: Transforming Undergraduate Education for Future Research Biologists (Nat’l Academy Press, 2003).

[2] National Research Council, A New Biology for the 21st Century (Nat’l Academy Press, 2009).

[3] AAMC/HHMI, Scientific Foundations for Future Physicians: Report of the AAMC-HHMI Committee (2009).

[4] AAAS, Vision and Change in Undergraduate Biology Education: A Call to Action (AAAS Press, 2011).

[5] E. F. Redish et al. “NEXUS/Physics: An interdisciplinary repurposing of physics for biologists,” Am. J. Phys. 82, 368–377 (2014).

[6] K. Moore et al. "Toward better physics labs for future biologists," Am. J. Phys. 82, 387-393 (2014).

Noon
Tome 115
Pizza provided

Monday, December 8th
Physics Senior Talks

Katie Roy & Andrew Chen - "Demonstrations in Ultrasound Imaging"
Sonography is a powerful imaging tool. From radar and sonar to ultrasonography, humans use inherent properties of waves for various imaging purposes. As a focus for our senior capstone project, we have decided to investigate ultrasound imaging techniques as they apply to the medical field. One of the most powerful tools of learning is the hands-on demonstration. In the spirit of workshop physics, this presentation will highlight our efforts to develop a series of coherent demos for undergraduate students exploring medical physics.

Tyler Ralston - "The Gridded Solar Air Heater"
With energy prices on the rise, and carbon emissions altering the Earth's ecosystem, renewable sources of energy need to be investigated. Photovoltaic cells are a popular renewable source of energy, but on average they have a conversion efficiency of 20%. The Solar Air Heater built by Professor Hans Pfister, Sung Woo Kim'13, and Rick Lindsey converts solar energy to thermal energy with a maximum efficiency of 80%. This talk will discuss the effect of the mass flow rate on the efficiency of the Solar Air Heater. Furthermore, a new technique for measuring the mass flow rate will be introduced.

Marc Besson - "Physics of Spin Waves on a 2-Dimensional Lattice"
Spin waves are quantum phenomena that arise on ferromagnetic and antiferromagnetic lattices. The easiest way to imagine spin waves is to consider them a the propagation of phase of the lattice magnetic moments. This thesis extends previous research in one dimension, looking instead at several different possible wave functions on a two dimensional lattice. The end goal of this research is to find the dispersion relations of the uniform mode, linear waves and spherical waves, and analyze the stability of each of these modes.

Ben Kimock - "A Computational Study of Spontaneous Energy Localization and Pattern Formation in Antiferromagnetic Spin Lattices"
Marc Besson's project theoretically investigates the dynamics of spin waves in generic lattices, but what do these spin waves actually look like, and what kind of behavior emerges from the interactions between spin waves? These are questions I will try to answer with a classical (not quantum) computational model for antiferromagnetic lattices. I have replicated Professor Lars English's results for 1-dimensional systems and have begun to observe related but somewhat novel and spooky behavior in 2-dimensional lattices.

4:30 p.m.
Tome 115
Light Refreshments Provided

Tuesday, December 9th
Physics Senior Talks

Nicholas Formus - "Time Difference between Different Paths"
Assuming there to be two identical balls traveling two different paths of equal length, which ball would get to the end faster? One of these paths is called the high road, which starts at some height and descends once and finishes at a lower height. Theother path is called the low road, which starts at the same height, descends twice, only to back up to finish at the same height as the high road. In order to determine this, newton kinematics are demonstrated to calculate the theoretical time difference between the two paths. This will then be compared to experimental data taken from a one of a kind high road/low road demonstration constructed, determining that the low road is fastest.

Devin Gaby & Robert MacKenna - "Faster than Freefall"
In this research project, we are looking at the rotation of rigid bodies about some fixed axis. Consider an industrial chimney falling down. As it falls, it rotates about the base, and before it hits the ground, it will fracture and collapse at multiple points in its body. This is due to the fact that as it rotates, different parts of the structure fall at different accelerations. We model this with a simple demo of a falling board with a ball resting on the tip. When the board falls, the board will hit the ground before the ball, showing the tip of the board is accelerating faster than gravity. We will also show that the acceleration of the board is a function of the distance from the axis of rotation. This can be applied to the case of the chimney, where this acceleration differential causes impressive internal forces inside the structure, resulting in it breaking before impact.

Prasad Bommana & Raheem Chowdhury - "Mechanics of Spinning Tops & the Perpetual Motion Top"
The basic mechanics behind a spinning top is studied in this research project. A simplified theory of the tops is investigated here using concepts available at introductory/intermediate level physics classes. The dynamic motions of the spinning top such as nutation, precession, rolling condition with a top's path trajectory is reviewed using theory and an experimental investigation. A brief extension into Tippe Top is also discussed regarding its unique property to spin in an upright position. Furthermore, the theoretical foundations for the Perpetual Motion Top is studied that integrates E&M concepts with classical mechanics.

Noon
Stafford Lecture Room
Pizza Provided

Thursday, December 11th
Physics Senior Talks

Marie Holden - "756 Lilliana: An Astronomical Controversy"
756 Lilliana is a C-type main-belt asteroid. There have been relatively few studies done on 756 Lilliana, and of these studies, many have presented conflicting light curves, rotation periods, and shapes. In my first semester of studying this asteroid, I have studied processes involved in differential photometry and have collected data from the NURO telescope at the Lowell Observatory in Flagstaff, Arizona. I have spent this semester analyzing the data from a single night of observation with the NURO telescope, and intend to use the data collected from all nights of observation to plot a full light curve.

Ben Koltz - "Development and Implementation of a New Data Acquisition Program for the Michael L. Britton 24-inch Telescope"
The Britton Telescope on campus provides a unique opportunity for taking astronomical data. My senior project aims to provide a better interface for taking data as well as additional tools for data analysis.

Michal Burgunder - "Superconductivity"

Noon
Tome 115
Pizza Provided