Monday morning
44
Portland
AA04:
8:30-8:40 a.m. Low-Cost Radar Sensor Kit for STEM
Education
Contributed – Scott MacIntosh, Black Cat Science, Inc., 70 Dwinell St., Bos-
ton, MA 02132;
Erik Bodegom, Erik J. Sanchez, Portland State University
A low-cost radar sensor kit has been developed for teaching a range of
STEM-related concepts and laboratory skills. The kit utilizes an inexpen-
sive commercially available off-the-shelf frequency-modulated continuous-
wave 24-GHz Gunn-diode based radar transceiver whose output frequency
is controlled by a 0-10 V control signal. Because the sensor utilizes a
homodyne detection architecture, signal outputs are typically in the low
kHz range, which allows for the use of inexpensive A/D devices for signal
capture and display. The novelty of the system is that with the same kit
one can teach introductory concepts at the high school level, such as basic
wave theory, to advanced concepts at the graduate level, such as image
reconstruction with diffracting sources. Currently, a system is being field
tested as part of an upper-level undergraduate physics lab at Portland State
University. Results of the preliminary test will be presented and discussed.
AA05:
8:40-8:50 a.m. Specially Designed Geiger-Mueller
Counter for Instrumentation Training
Contributed – Yongkang Le, Fudan University, No. 220 Handan Road, Shang-
hai 200433;
Shuo Wang, Fudan University
Instrumentation, defined as the art and science of measurement and con-
trol of process variables within a production or manufacturing area,
1
is one
of the important contents in frontier research. However, training on instru-
mentation is far from sufficient in teaching laboratories. Geiger-Mueller
counter is widely employed for radiation detection. Characterization of a
Geiger-Mueller counter is a typical teaching laboratory for students beyond
the first year. Due to the long resolution time (in the order of 100 micro-
second), the dynamic range of a typical Geiger-Mueller counter is limited
to about 3000 counts per second. With the help of a differential circuit, the
resolution time could be reduced significantly, thus extends the dynamic
range of the Geiger-Mueller counter. Teaching practice based on such a
device aiming the basic training on instrumentation will be reported.
1.
.
AA06:
8:50-9 a.m. The Millikan Experiment Without Oil Drops
Contributed – Gerald Feldman, George Washington University, Department
of Physics, Washington, DC 20052;
Students learn about the Millikan Oil Drop experiment in their Modern
Physics courses. Some courses have associated labs in which students actu-
ally perform the experiment, at the risk of going blind by following tiny
illuminated droplets for many minutes. Since the value of this experiment
lies in the analysis, a clever way to circumvent the difficulties of using oil
drops was developed
1
in which discrete masses are measured (instead
of discrete charges). By weighing film canisters with a finite number of
marbles hidden inside, the same analysis can be applied to determine the
“unit mass” of an individual marble. The experiment is simple to execute,
very little equipment is needed, and students are challenged to deduce an
analysis method that will yield an accurate result. Since my course at GWU
has no formal lab, this was an ideal classroom activity that required little
time but provided a large pedagogical payoff. I report on such a trial in the
spring 2013 semester, including student results and reactions.
1. Eric Ayars, AAPT Workshop at the Summer 2008 Meeting (Edmonton, AB).
AA07:
9-9:10 a.m. Force-Distance Curve Reconstruction
Experiments Using a Multi-Frequency Atomic Force
Microscope
Contributed – Yingzi Li, Beihang University, College of Applied Physics,
Xueyuan Road No. 37, Haidian District, Beijing, China 100191;
Liwen Zhang, Jianqiang Qian, Hua Li, Beihang University
The signals from atomic force microscope (AFM) contains all the infor-
mation of an interaction. Analyzing these signals can be very useful for
researchers to understand the interaction. In this paper, the force curve,
which indicates the interaction status, was obtained from AFM signals. Its
corresponding frequency spectrum is produced by using Fourier trans-
form, and higher harmonics are extracted from the spectrum to recon-
struct the force curve. This method depends on the study of the motion of
cantilever, which can be achieved using a platform built in the labora-
tory. A special external dual-frequencies driver was used in force curve
reconstruction experiments to enhance the produced signals because they
were too weak to detect. Consequently, the force curve can be obtained by
this method and experimental platform. In the beginning of the paper, the
method shown above was introduced and then the result of force curve
reconstruction experiment based on it was subsequently discussed. The
experiment is expected to be a part of physical experiment courses.
Early Career Professionals Speed Networking Event
Monday, July 15
12 -1:30 p.m.
Skyline IV
Discuss career goals and challenges
with one colleague for five minutes…
…and then move on to the next.
