Application of the Rensselaer Mobile Studio I/O Board in an Introductory University Physics Course*

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Application of the Rensselaer Mobile Studio I/O
Board in an Introductory University Physics
Course

• Peter D. Persans1, Stephanie Tomasulo1, Gwo-Ching
  Wang1,
• and Don L. Millard2
• 1Physics, Applied Physics, and Astronomy
• 2Electrical, Computer Systems Engineering
• Rensselaer Polytechnic Institute, Troy NY
• (work supported by the NSF)

persap_at_rpi.edu http//ioboard.rpi.edu
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Physics in the Rensselaer Studio Model

• Two two-hour studio classes per week
• Reading quiz
• Homework review
• Short lectures on new material
• Quick feedback questions
• Experimental/conceptual activity
• 48 students in 16 groups of 3
• One professor, two TAs

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Some Issues with the Studio Model

• Studio pedagogy uses dedicated spaces and
  laboratory instrumentation
• One experimental set-up for three students
• Studio facilities need staff and maintenance
• Studio activities must be accomplished quickly
  and efficiently
• Students dont get sufficient exploratory time in
  the studio mode.
• Timing and equipment expense constrains
  activities
• One student frequently dominates activity

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Physics II at Rensselaer

• Electric fields, forces, potential
• Gauss Law, Capacitors, DC circuits
• Magnetic fields and forces
• Fields from currents
• Faradays Law and inductance
• AC circuits
• Maxwells equations and electromagnetic waves
• Waves and oscillations
• Wave interference, diffraction
• Concepts in quantum physics

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A typical experimental activity

• Wave Interference - Beats
•  In this activity, students create audible
  signals using two audio function generator
  programs on their laptops. The audio signal is
  picked up with a microphone and observed on an
  oscilloscope. When the frequencies differ, a
  beat signal is observed.
•  
• Equipment
• PC function generator (2)
• 2 channel oscilloscope
• Audio pick-up microphone

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So what if ?

• We could enable students to perform
  sophisticated, quantitative experiments anyplace
  at anytime
• Dormitory room
• Student Union
• Library
• Campus meeting rooms
• Etc.

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The Mobile Studio
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RED2 I/O Board Specifications

• Operates through USB port of PC
• 2 A/D inputs, configured as a dual channel scope
  (1.45MS/s)
• 2 D/A (FG/AWG) outputs
• 2 PWM output ports
• 16 Digital outputs/inputs (software configurable)
• /- 4v, 3.3v, 5v Power supplies (capable of
  delivering 100mA)
• A wireless transceiver for remote sensing
  control
• An audio amplifier (stereo headphone jack on the
  board)

150
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Mobile I/OBoard Activity Development

• Fall 2007 develop I/OBoard versions of studio
  activities that use oscilloscope and function
  generator (7 out of 20 activities)
• Spring 2008 try out activities in our Honors
  Physics II course labs
• Fall 2008 IOBoard based activities were run for
  one Studio section (out of twelve parallel
  sections)
• Most students purchased/borrowed an IOBoard with
  electronics kit
• Each student had to perform most activities

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Mobile I/OBoard Activities - F2008

• Setting up/using the oscilloscope
• AC voltage divider (C1-C2)
• RC and RL decay
• AC reactance (RL, RC)
• Diode IV curve
• LC ringing
• RLC resonance
• Audio frequencies and hearing
• Audio beats
• take-home activity component

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The Mobile Studio Audio Beats Activity

• Dual function generator on IOBoard is used to
  generate periodic signals
• Function generator output drives headphones or
  amplified speakers directly.
• Dual oscilloscope plus math functions are used to
  observe output to speakers plus sum signal.
• Audio or function generator output can drive
  filter circuit.
• Filter output can be viewed on oscilloscope
  screen and heard.
• Students can explore sound and circuit behavior
  outside of class.
• Students can store waveforms in csv format for
  later analysis

see handouts
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The Mobile Studio User Interface
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Evaluation overview

• Students in regular studio and mobile studio
  class had same lectures, similar activities, took
  same exams.
• Class to class comparison was performed on all
  test items and overall.
• Student input gathered via online IDEA forms.
• Student input gathered via in-class surveys.

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Example test item

• _____A1) The root mean square (rms) value of the
  emf in Fig. A1-4 is closest to 
• A) 10V B) 20 V C) 14 V D) 7V E) 0V
•   
• _____A2) The frequency in Hz of the oscillating
  emf in Fig. A1-4 is closest to
•   A) 500 Hz B) 5000 Hz C) 3070 Hz D) 200 Hz
  E) 2x10-4 Hz

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Example test item C-1

• The RC circuit shown below is driven with a
  harmonic emf of
• .
• The value of the resistance is 1000 ohms.  
• a) Write an equation for the reactance of the
  capacitor as a function of frequency f.
•  b) At a driving frequency f10,000 Hz, the
  amplitude of the voltage across the resistor is
  the same as that across the capacitor. What is
  the value of the reactance of the capacitor at
  this frequency?

c) What is the value of the capacitance?  d)
What is the amplitude of the voltage across the
capacitor at 10,000 Hz? Explain your answer.
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Mobile Studio results

• Performance on classwide tests was compared.

average MSG 3.47 4.00 3.73 3.73 2.13 0.80 2.67 1.33 3.73 3.20 4.80 7.40 7.20 6.27 9.73 13.00 77.20
Average, control 2.86 3.81 2.76 2.67 3.05 1.90 2.10 1.33 3.62 3.05 4.05 7.86 7.48 6.71 7.88 12.93 74.05


A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 B1 B2 B3 B4 C1 C2
diff 4-5/stdev (4-5) 1.30 1.43 2.43 2.64 -1.49 -2.04 0.94 0.00 0.34 0.30 1.57 -1.06 -0.65 -0.55 1.79 0.10 0.86
Green Mobile studio group gt1 deviation above
control group. Red Control group gt Mobile
studio group. Problems A1-A4 and C1 involved
interpretation of oscilloscope graphs and ac
circuits. Mobile Card class consistently
overperformed on oscilloscope and ac circuits
problems. Their performance on other material was
randomly above and below average.
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Why the difference?

• Each student in Mobile Studio class performed the
  activity himself/herself.
• Digital data storage permitted later analysis and
  plotting.
• Use of IOBoard outside of class
• Assignments
• Students played with the audio functions
• Students interface differently with GUI than with
  knobs
• With Mobile interface they have to choose the
  scales rather than twiddle knobs.

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Future work

• Expand activities to include use of boards
  outside of class
• Design activities to take advantage of special
  IOBoard features
• audio amplifier output
• digital data storage
• Expand implementation to hundreds of students
• Add wireless daughter card with accelerometer,
  force gauge, position sensor

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Contact Information

• Peter D PersansDepartment of Physics, Applied
  Physics, and AstronomyRensselaer Polytechnic
  Institute110 8th Street, Troy NY
  12180persap_at_rpi.edu www.rpi.edu/persap
• For I/O Board informationmillard_at_rpi.edu
  http//ioboard.rpi.edu