Spring 2013 - Glenbard South

Registration and Continental Breakfast

Welcome

Next Generation Science Standards

Carol Baker, Director of Curriculum for Science and Music for Community High School District 218

Physics of Banjos

Joe Bella, Alex Gilman, Tom Sullivan, David Wieczorek, Loyola University Chicago

The banjo is an instrument that has not been studied very thoroughly in the realm of physics of musical acoustics. Our objective of this research was to achieve a greater understanding how string harmonics contribute to the timbre of the instrument and to understand which, if any, drum modes were expressed by the instrument. Furthermore, because the instrument incorporates facets of both a stringed instrument and a drum, we wished to achieve a greater understanding of the relationship and interplay among the string harmonics and drum modes of the instrument. We strummed the banjo strings at different locations to determine the effect of initial conditions on the sound and timbre of the instrument. Using Chladni patterns, we observed various drum modes and correlated those with the string resonances. We noticed strong correlation between some of the string resonances and drum modes. We will discuss results and the plan for future work.

Modeling Modern Physics Phenomena and Applications Using G4Beamline

Joe Kozminski and Elizabeth De Waard, Lewis University

G4Beamline is a freely-available, user-friendly, text-based front-end to the powerful GEANT4 simulation tool commonly used by particle physicists. Students and teachers are able to download G4Beamline and simulate particle beam interactions with targets very quickly using example files provided. Without too much difficulty, G4Beamline input files can be modified to simulate various kinds of scattering experiments. G4Beamline can provide both a graphical depiction of single events and datasets of particle position and momentum information (and other useful information) in ROOT files. G4Beamline can be used in educational settings including Modern Physics and Particle Physics courses and QuarkNet projects.

Break

Dimension and Probability

Ted Erikson, R/E UnLtd.

In Mathematics a "point" has no "dimension". Physics suggests it as a "probability", i.e. the "Big Bang". Are meanings of the quoted words totally understood? Summing up an intensive web search, dimension is a hyperbolic synonym with many definitions, while probability is either objective (possible result of experimental outcomes) or subjective (e.g. Bayesian). Dimension and probability appear as significant in an FQXi physics essay* contest that I entered last summer to define panpsychism. Three points define a 2-D equilateral triangle. Assume one as origin for all possible trees, i.e. sequentially (1-2-3 or 1-3-2) or simultaneously (1-2&3). A line (1-D) and an area (2-D) evolve respectively with probabilities of 2/3 and 1/3, as may be expected. Extrapolating this dimension-probability evidence confirms 100% and 0% probabilities for a point (0-D) and 3-D. However, vertices of a 3-D regular tetrahedron as 4 points, treated similarly as 16 trees, displays evidence that extrapolate to minus 1-D and ~4-D. For a 4-D pyramid, (minus ~1/2)-D and ~7-D appears. Likely here, a 50% probability for a sphere at any dimension may occur, as quantum theory suggests. Are dimension and probability really understood?

Musical acoustics of stringed instruments

T. Predey, R. Galbo, J. Kamberos, Z. Momin, and K. Pomian, Loyola University Chicago

We are studying the properties of stringed instruments that contribute to their unique sounds and yet, set them apart. The goal is to understand how stringed instruments function, and what sets the different instruments apart in sound and function. We have analyzed the string resonances and body properties of guitars, violins, cellos and dulcimers. We analyzed sound data for each instrument under different initial conditions. The strings were excited at different locations using various techniques, such as plucking and bowing. A cross comparison of the instruments revealed variances in the sound based upon the unique characteristics of each. This project provides a comprehensive analysis of stringed instruments.

Observing Electric Dipole and Quadrupole Effects from Scattered Laser Light

Ernest Knight and Joe Kozminski, Lewis University

We have developed an apparatus that allows us to directly observe electric dipole and quadrupole effects resulting from the scattering of polarized laser light. When the polarized electromagnetic radiation is incident on a material, the electrons of the scattering atoms are driven into forced oscillations about the positively charged nucleus, in turn producing their own electric dipole radiation. This radiation is emitted perpendicular to the direction of incident light. Multiple factors influence the angular intensity distribution of the scattered light, including the intensity, frequency, and polarization of the incident radiation and the concentration, spatial arrangement, size, and optical properties of the scattering centers. In materials with scatterers significantly smaller than the wavelength of the incident light, the largest component of the scattered light! is the dipole radiation from the oscillating electrons. In this experiment, polarized light from a 633 nm laser is incident on a dilute solution of skim milk and water, with the long chain molecules, called caseins, in the milk acting as scattering centers. The intensity of the light scattered perpendicular to the incident beam is measured by a power meter as the polarization of the incident light is changed. The expected dipole scattering effect is observed, and by rotating a polarizer between the sample and the power meter, a quadrupole effect is also observed. The design of this experiment is now being optimized for use in undergraduate labs and demonstrations.

Resistivity of Conducting Paper

Martha Lietz, Niles West High School

Conducting paper from PASCO and other vendors can be used to make resistors of various lengths and widths. Students can then use an ohmmeter or Ohm’s law to determine the relationship between resistance and length, or resistance and cross-sectional area. More advanced students can be required to calculate the resistivity of the paper using their graphs as well. Some interesting results from my AP classes’ recent experiments will be shared and discussed, as well as potential improvements to our experimental design.

Take-fives

Lunch (Business Meeting and Update from AAPT)

Workshop: Cosmology in the Classroom

Kim Coble, Chicago State University

Recently, powerful new observations and advances in computation and visualization have led to a revolution in our understanding of the structure, composition, and evolution of the universe. Experts should not be the only ones who understand the physics and data that provide overwhelming evidence for big bang cosmology. This workshop will introduce participants to the results of our research on common alternate conceptions students hold regarding distances, structure, age, evolution, and composition of the universe. Participants will also have the opportunity to use interactive web-based activities from a curriculum informed by this research that are designed to help students master the scientific concepts and processes that lead to our current understanding of the universe.