Bulletin of the American Physical Society
Joint Fall 2010 Meeting of the APS Ohio Section and AAPT Appalachian and Southern Ohio Sections
Volume 55, Number 8
Friday–Saturday, October 8–9, 2010; Marietta, Ohio
Session C3: Education, Astronomy, and Gravitation |
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Chair: Ann Bragg, Marietta College Room: Anderson Hancock Planetarium |
Saturday, October 9, 2010 8:00AM - 8:12AM |
C3.00001: Quantized Conductance in Mechanically Controlled Break Junctions for Undergraduate Labs Robert Tolley, Daniel Wentzel, Antony Silvidi, Khalid Eid We have constructed a system to demonstrate quantized conductance steps through mechanically controlled break junctions in gold wires [1]. This apparatus is designed to use simple and robust parts with the intention of making it conceptually accessible as an experiment in an undergraduate laboratory. Unlike more common methods of using piezo-electric crystals, our apparatus relies upon a stepper motor and simple reduction gears to achieve the necessary atomic level resolution. This experiment allows a clear and intuitive investigation of four distinct regimes of charge transport in physics. Starting at the macroscopic (i.e. diffusive transport regime), pulling the wire allows us to reproducibly probe transport in the mesoscopic, quantized conductance, and finally quantum tunneling regimes. Despite the very simple tabletop design, this device allows students to directly observe the transition between the classical world and the one dominated by quantum mechanics. We specifically developed this setup for use in the sophomore-level contemporary physics lab at Miami University.\\[4pt] [1] N. Agrait, A.L. Yeyati, J.M. Van Ruitenbeek. Physics Reports 377, 81 (2003) [Preview Abstract] |
Saturday, October 9, 2010 8:12AM - 8:24AM |
C3.00002: Assessment of Student Learning in Modern Experiments in the Introductory Calculus-Based Physics Labs Brian Woodahl, John Ross, Sarah Lang, Derek Scott, Jeremy Williams With the advent of newer microelectronic sensors it's now possible to modernize introductory physics labs with the latest technology and this may allow for enhanced student participation/learning in the experiments. For example, force plate sensors can digitize and record the force on an object, later it can be analyzed in detail (i.e, impulse from force vs. time). Small 3-axis accelerometers can record 3-dim, time-dependent acceleration of objects undergoing complex motions. These devices are small, fairly easy to use, and importantly, are likely to enhance student learning by ``personalizing'' data collection, i.e. making the student an active part of the measurement process and no longer a passive observer. To assess whether these new high-tech labs enhance student learning, we have implemented pre- and post- test sessions to measure the effectiveness of student learning. Four of our calculus-based lab sections were used: Two sections the control group, using the previous ``old technology'' labs, the other two, the experimental group, using the new ``modern technology'' labs. Initial returns of assessment data offer some surprising insight. [Preview Abstract] |
Saturday, October 9, 2010 8:24AM - 8:36AM |
C3.00003: Update on IMPACT II Gordon Aubrecht We are currently in the third year of a project that began at Marion's Grant Middle School and has spread to Harding High School. I will give information on some changes middle school teachers have made and indicate how the high school teachers became involved. [Preview Abstract] |
Saturday, October 9, 2010 8:36AM - 8:48AM |
C3.00004: Experience with a yearlong middle school astronomy experiment Gordon Aubrecht This report involves the astronomy focus in eighth grade science and development of our own astronomy unit that would address major parts of Ohio standards. Our intent in this astronomy experiment was to address this problem directly by instituting an investigation that would occur over the school year. We chose not to tell students about Sun and Moon motions and prove our assertions through observations; rather, we asked students to observe and infer these motions. As often happens, only part of what we planned was implemented the first year. Few Moon observations were ever made by students, who were expected to do this at home; in some classes, this improved the second year of the project. The Sun observations were carried out over the school year because they were done at school and because some of our teachers were committed to doing them. Sun shadows were observed several times a month by students and the tip of the Sun shadow was indicated by a blob of paint on the surface of a wood platform the first year. The second year, the observations were made using a golf tee mounted on posterboard as a gnomon. Each observation day resulted in up to 12 blobs, depending on how many classes participated. We present the results of the two yearlong investigations and speculate on whether this could be a useful way to address students' general misconception of science as a series of 45-minute experiments. [Preview Abstract] |
Saturday, October 9, 2010 8:48AM - 9:00AM |
C3.00005: The Effects of a Variable Torque on Neptune's Satellite Nereid Andrew Hesselbrock, Stephen Alexander Neried is a small satellite of Neptune orbiting in a highly elliptical orbit. As Nereid is most likely a non-spherical object, we use a computer model to demonstrate how Nereid's highly elliptical orbit gives rise to a variable torque large enough to affect its rotation. We feel this variable torque and consequent perturbations may explain the measured variations in Nereid's brightness. Performing simulations changing such variables as Nereid's obliquity, shape, and spin rate we are able to produce active and inactive time periods of oscillation that may provide some insight into visible observations. [Preview Abstract] |
Saturday, October 9, 2010 9:00AM - 9:12AM |
C3.00006: Weak Lensing Analysis of Cluster Merger Abell 1758 Brett Ragozzine, Douglas Clowe, Maxim Markevitch A1758 is an ongoing merger between two galaxy clusters and the weak lensing results show the total gravitational potential of the system to be offset from the X-ray gas distribution for just one of the clusters. This result is different than previously published mergers (Bullet cluster and MACS J0025.4-1222) because they show an offset between the total mass of the system from the X-ray gas for both clusters. The new geometry of A1758 provides a way to test MOND gravity models such as Tensor-Vector-Scalar. [Preview Abstract] |
Saturday, October 9, 2010 9:12AM - 9:24AM |
C3.00007: Dark Physics: Resurfacing the universe James Beichler In the past few decades two new ``crises'' for fundamental physics have emerged by the observation and confirmation of Dark Matter (DM) and Dark Energy (DE). These are not problems which can be solved by quantum theory, but rather problems that are related to gravity theory as expressed by curved space-time as expressed in the general theory of relativity. Numerous ideas and hypotheses have been suggested to explain these problems, but no particular hypothesis or resulting model has proven satisfactory - no model yet proposed seems to be able to explain both DM and DE even though many physicists agree that the two should have a single common explanation, implying that the physics of DM and DE lies outside of the present paradigms and interpretations of physical reality. However, one new model has been developed that can simply explain both DM and DE. This model includes a fundamental change in Newtonian gravity theory that expands three-dimensional space to four dimensions and thus forces the acceptance of an extrinsically curved four dimensional space-time. The extra term added to Newton's gravity can then be equated to the Lambda-CDM that has been added to the Einstein equation. Accepting this new model would mean accepting the existence of a macroscopically extended fourth space-like dimension, which changes all of physics to some degree. [Preview Abstract] |
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