50
Sunday afternoon
mimic the closed elliptical orbits of the planets--or not--by carefully
selecting the conical angle and the ball’s moment of inertia. Learning-
by-contrast, at least for this author, is effective, and its benefits far
outweigh any disappointment that celestial phenomena are not
reproduced precisely.
*Gary D. White and Michael Walker, “The shape of ‘the Spandex’ and orbits
upon its surface,”
Am. J. Phys
.
70
, 48 (2002).
BF04:
5-5:10 p.m. What Frame of Reference Is Your
Smartphone Accelerometer In?
Contributed – Jonathan C. Hall, Pennsylvania State University - The
Behrend College, Erie, PA 16563-0203;
Accelerometers such as found in smartphones respond to both ac-
celeration caused by contact forces, and also to the gravitational field
intensity when not accelerating. (When the device is accelerating in
free-fall, the reading is zero.) The resulting measurements from the
“smart” devices have been incorrectly reported as the acceleration
several times in
The Physics Teacher
. Strategies for correcting this
misunderstanding of acceleration will be discussed.
BF05:
5:10-5:20 p.m. Weapons Development in
Revolutionary France
Contributed – Ruth H. Howes, Ball State University, emerita, 714 Agua
Fria St., Santa Fe, NM 87501;
On March 30, 1775, Controller General Anne Robert Jacques Turgot
appointed the French chemist Antoine Lavoisier to a commission
with three other members to run his newly created Gunpowder and
Saltpeter Administration. As a perk, Lavoisier was given an apartment
in the Arsenal belonging to the Gunpowder and Saltpeter Administra-
tion with ample space to establish a chemical laboratory. Lavoisier
developed better methods for producing gunpowder which enabled
the surplus supply which France used to supply the American rebels
in their war with the British. Lavoisier and his colleagues worked in
an effort to develop more effective explosives to reverse the French
military defeats that marked the end of the ancient regime and the
initial efforts of the revolutionary government to defend itself against
most of the rest of Europe
BF06:
5:20-5:30 p.m. Increasing AP Test Scores
Contributed – Thomas F. Haff, Issaquah High School, Issaquah, WA
98027-4319;
The evidence of increased AP (C exam) scores is anecdotal, but my
students have experienced increase scores on the exam. This talk is
not about increasing physics knowledge but how time-saving tips
coupled with simple instructional techniques will give students more
confidence and increased scores. 98% of my past students have passed
the exam.
Session BG: Optics Labs Beyond
the First Year
Location: Salon 9
Sponsor: Committee on Laboratories
Co-Sponsor: Committee on Apparatus
Date: Sunday, January 5
Time: 4:30–6 p.m.
Presider: Gabe Spalding
BG01:
4:30-5 p.m. Open-ended Laboratory Projects in an
Undergraduate Lasers Course
Invited – Chad Hoyt, Bethel University, St. Paul, MN 55112;
We describe the format and experience of an undergraduate Lasers
course at Bethel University. The course, which includes a standard,
rigorous lecture portion, is built on open-ended research projects
that have a novel aspect. It begins with four weeks of small student
groups rotating between several standard laser laboratory exercises
such as alignment and characterization of a helium neon laser. During
the remainder of the course, student groups (2-4 people) choose and
pursue research questions in the lab. Their work culminates in a group
manuscript typeset in LaTeX and a 20-minute presentation to the
class. Projects in the spring 2013 Lasers course included ultrafast op-
tics with a mode-locked erbium fiber laser, quantum optics, saturated
spectroscopy of indium, nano-optics and plasmonics (led by Nathan
Lindquist), and improvements to a lithium magneto-optical trap. The
experience in Lasers is representative of other upper-level courses at
Bethel, including Optics, Fluid Mechanics and Computer Methods.
BG02:
5-5:10 p.m. A Collection of Laboratory Projects for
Modern Optics and Photonics
Contributed – A. James Mallmann, Milwaukee School of Engineering,
Milwaukee, WI 53202;
I will describe some of the 58 laboratory projects produced for the
curriculum development project Optics and Photonics for the 21st
Century—An Innovative Interdisciplinary Modular Laboratory Cur-
riculum.* Each module includes a historical note and, if appropriate,
biographical sketches; a discussion of practical applications; a discus-
sion of the fundamental physics and mathematics for the projects; a
statement of goals for a collection of projects; questions and problems;
and a list of references. None of the projects are of the “cookbook”
variety, and, except for the first module, for which an optical power
meter is used, all the projects can be performed using equipment
that is likely to be available in a typical college physics or engineering
laboratory.
*Supported by NSF grant DUE-9555048.
BG03:
5:10-5:20 p.m. Optics in Advanced Laboratory
Experiments
Contributed – Robert Deserio, University of Florida, Gainesville, FL
32611-8440;
Stephen J. Hagen, University of Florida
We will report on the construction and progress made with two new
optics-based experiments for the advanced lab: an optical tweezers
and a molecular fluorescence correlation spectrometer. Optical twee-
zers trap micron-sized particles in suspension using a laser focused
through a microscope objective. The scattered light is detected to
encode the particle position as it is buffeted by Brownian forces.
The position power spectrum is analyzed for the restoring force and
damping. In the molecule fluorescence apparatus, a laser is focused
through a microscope objective where fluorescing particles are
suspended. The fluorescing volume is imaged at high magnification
where a pinhole is positioned. Behind the pinhole, enhanced photon
rates are observed when as few as one fluorescing molecule traverses
the focal volume. The photon stream is analyzed for the focal geom-
etry, the average number of molecules in the volume, and properties
associated with diffusion and fluorescence. This work supported by
NSF DUE award 1139906.
BG04:
5:20-5:30 p.m. Spy Physics: Using a Laser to
‘Hear’ a Conversation
Contributed – Timothy Todd Grove, IPFW, Fort Wayne, IN 46805;
Trunghieu T Nguyen, IPFW
We will present a simply constructed laser experiment for students
beyond their first year in physics. The goal of this particular experi-
ment is to not only give students experience with laser interferometry,
but to allow students to have greater excitement than they would nor-
mally get counting fringes or making precision measurements. Our
experiment started when a student asked “Is it true that you could
use a laser beam to detect a conversation in an office by its reflection
off of a window.” To accomplish this task we used a simple Michelson
interferometer in which one mirror vibrated in response to a sound
source. A speaker connected to a radio inside a small box with a
