114
Portland
Wednesday morning
PST2F19: 8:30-9:15 a.m. Equipotential Color Coding from Fields
to Circuits
Poster – John Avallone, Stuyvesant High School, 9707 Fourth Ave., Brooklyn,
NY 11209;
When presenting the concept of equipotential surfaces in the Electric field
unit, it is useful to use colored chalk to show the set of points at a given
potential. With this established, it can be useful again to color the portions
of circuit diagrams that are all at equal potential. With this illustration,
students can easily distinguish parallel paths between equipotential “zones”
and thus see the simplification of complicated circuits easily.
PST2F20: 9:15-10 a.m. Investigating Students’ Difficulties in
Charging by Induction: Analysis of Student Data
Poster – Lynda Klein, California State University, Chico, Department of Phys-
ics, Chico, CA 95929;
Steven Sun, Chico High School
Yibo Zhang, Benjamin Catching, Xueli Zou, California State University, Chico
In this paper we will present the results of data recently gathered using vid-
eos made to collect and analyze student?s difficulties in charging by induc-
tion in the introductory calculus-based EM course. Not only do students
have difficulty learning but also their instructors have difficulty teaching
charging by induction (ref). Ref: “Charging an electroscope by induction.”
Vol.
3
, pp. 29,
TPT
Jan. 1965.
PST2F21: 8:30-9:15 a.m. Addressing Students’ Difficulties in
Charging by Induction: Creation of Experimental Videos
Poster – Steven Sun, Chico High School, 901 Esplanade, Chico, CA 95929;
Yibo Zhang, Benjamin Catching, Lynda Klein, Chris Gaffney, California State
University, Chico
As part of the efforts in addressing student difficulties of charging by
induction, we made a series of instructional videos in which an electro-
scope is charged by charged rods. Students are prompted to explain with
conceptual reasoning and models, predict using words, and sketch the phe-
nomena they see, including a testing experiment to convince them of the
outcome. This paper will show how we used the videos with our introduc-
tory students and discuss subtlety of physics beyond the phenomena.
PST2F22: 9:15-10 a.m. A New Spinning Coil for Measuring the
Earth’s Magnetic Field
Poster – Chris Kaneshiro, California State University, Chico, Department of
Physics, Chico, CA 95926
Daniel Lund, Xueli Zou, Eric Dietz, California State University, Chico
Steven Sun, Chico High School
A common way of measuring Earth’s magnetic field in an introductory
physics lab is by spinning a coil, and using an oscilloscope to analyze
the induced emf. The coil is typically rotated by a motor, but we have
constructed a device that uses a falling mass instead. Our device includes
an angular velocity sensor and leads for a voltage sensor, so the frequency
of rotation can be analyzed in addition to the induced emf. Problems that
arise with motorized spinning coils include noise from the generator and
large repair costs, but by replacing these motorized models with out ap-
paratus, we are able to not only develop a more efficient way of measuring
Earth’s magnetic field, but also richer data for students to analyze.
PST2F23: 8:30-10 a.m. Curvature of the Universe CMB Lab for
Non-Science Majors*
Poster – Daniel M. Smith Jr., South Carolina State University, PO Box 7709,
Orangeburg, SC 29115;
Measurements of fluctuations in the Cosmic Microwave Background
(CMB) by the WMAP and Planck satellites have resulted in increasingly
precise determinations of cosmological parameters that characterize the
curvature, matter fraction, and dark energy fraction of the universe. But
the colorful map of temperature fluctuations and the graph of the power
spectrum have little physical meaning for the non-expert. To surmount
the barrier to understanding the physics represented by these data
products, a lab has been developed to enable students to determine the
curvature of the universe by comparing actual WMAP data to theoreti-
cal maps and power spectra that students themselves calculate using the
CAMB web interface.
*Funded by the South Carolina Space Grant Consortium/NASA EPSCoR
PST2F24: 9:15-10 a.m. Fresnel Equations with Complex Index
of Refraction, Theory and Experiment
Poster – Scott A. Gimbal, California State University, Chico, Department of
Physics, Chico, CA 95926;
Anna Petrova-Mayor, California State University, Chico
The Fresnel equations describe the amplitude and phase shift of light
when reflected and/or refracted at the boundary between two media
with different index of refraction. If the medium is conductive, such as
gold for example, the index of refraction is complex. We will discuss how
to evaluate the Fresnel equations for metallic coatings. We will present
experimental data for the performance of a gold coated mirror for 45o
incidence and linearly polarized laser beam. The experimental results will
be compared with the theoretical prediction.
PST2F25: 8:30-9:15 a.m. Using Tablets to Augment and
Standardize Teaching of Introductory Labs
Poster – Larry Bortner, University of Cincinnati, PO Box 210011, Cincinnati,
OH 45221-0011;
Instructor preparation is very important in the student retention of
knowledge in the physics laboratory. In the traditional physics laboratory
setting, graduate teaching assistants and undergraduate learning as-
sistants serve passably well because of their familiarity with the material.
However, in the transition from traditional labs to labs that are more
student-directed rather than cookbookish, instructors can become lost
and may revert to the more comfortable habit of giving students all the
answers, thus subverting the process. The use of a Kindle tablet loaded
with TA instructions, hints, warnings, and suggested questions to ask
students at targeted points in the student investigation offers stress reduc-
tion for the TA and promotes a more uniform instruction level.
PST2F26: 9:15–10 a.m. Locating Introductory Mechanics
Problems Along the Well-structured – Ill-structured
Continuum
Poster – Jeffrey A. Phillips, Loyola Marymount University, One LMU Drive,
MS 8227, Los Angeles, CA 90045;
Dante Sblendorio, Loyola Marymount University
Problems, across all disciplines, are typically described as either being
well-structured or ill-structured. Simplistically, well-structured problems
are defined as those where the goals and parameters are clearly stated
and ill-structured as those that lack necessary information, which often
leads to multiple solutions. We have found that those definitions do
not completely capture the range of complexities that can be found in
problems. Instead of this binary description, we prefer to view problems
as lying along a continuum where their complexity and difficulty depend
on, among other things, the fraction of conditions that are unstated in
the problem. This fraction can take on any value, with larger ones imply-
ing that a solver to make the more decisions when creating a plan. We
will present our coding scheme, which includes many other factors such
as reading comprehension level and number of relevant physics concepts,
and several example problems.
