PHYS250 Laboratory Redesign

Alastair McLean

August 15, 2018

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Slate of PHYS250 Experiments

Experiment Status

Mechanical Resonance ProceduralBending Beams and Strain Gauges ProceduralCoupled Oscillations DesignThe e/m Ratio ProceduralDamped Harmonic Motion ProceduralDiffraction from a CD DesignElectrical Resonance ProceduralH/E And The Photoelectric Effect ProceduralInterference and Diffraction of Ultrasound ProceduralYoung’s Modulus of Steel DesignFerromagnetic Hysteresis Procedural

Three out of 11 are Design Labs. Eleven labs × 2 setups × 2 students = 44. The first week is

tutorial labs and there are again 22 setups × 2 students = 44.

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Student Numbers

Year Enrollment2019 502018 432017 392016 332015 342014 28

The ENPH second year labs splits into two sections when the en-rollment > 28.

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The STANDARD MODEL of Laboratory Instruction =Procedural Laboratory

. . .

From the Ferromagnetic Hysteresis Outline

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Procedural Workflow

For n =1 ... Nread and execute proceduralitem # n

0.0

time

Think about the Physics

Test the results

Ask for more time

Write the report

Problem(s)o.k.

(hours)

2.X

“I never read an outline before I came to the lab”

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What is wrong with Procedural Labs?

Science as it is taught should closely resemble science asit is practiced by professional scientists.

Whatever taxonomy of thinking you use, you should aimto have your students operate in the higher levels.

Laboratories should foster minimally restrictive free ex-ploration rather than the prescriptive adherence for for-mal procedure.

Self-directed Learning: A heretical experiment in teaching physics, Mark Silverman, Am. J.

Phys. 63 (6) 495-508, 1995

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nλ = d(cosϕn − cosϕ◦)

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Design Workflow

Execute your procedure0.0

time

Think about the Physics and make a plan

Test your results

Write your report

Problem(s)

o.k.(hours)

3.0

Read the outline and discover the task

Re�ne

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Our Responsibility as Laboratory Instructors

• To draw the students into the field by exposing them to inter-esting phenomena.

• To raise questions that students find personally meaningful.

• To support the students while they devise their own proce-dures and try things out.

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A new Design Lab involving Coupled Systems

Coupled pendulums, are demonstrated by Professor Roger Bowley as part of little Easter se-

ries. He’s using creme eggs, of course. Sixty Symbols. YouTube

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Connections to Quantum Physics

Coupling systems together produces symmetric and antisymmet-ric eigenstates with an energy/frequency splitting. e.g. covalentbonding and quantum wells:

Energy versus barrier width r.

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Coupled Oscillators in the Literature.

• Coupled oscillators: interesting experiments for high schoolstudents, Phys. Educ. 53, 045021 (2018), C Kodejska , OLepil and H Sedlácková. Magnetic coupling and electricalequivalent circuits.

• On coupled mechanical harmonic oscillators, transients andisolated oscillating systems, Lance McCarthy, American Jour-nal of Physics, 71 6 (2003). Magnetic coupling.

• The coupled harmonic oscillator: Not just for seniors any-more, Norris Preyer, The Physics Teacher, 34, 52-5 (1996).Masses coupled by springs on air track.

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PHYS250 Towards an Open Source Hardware Kit

Prototype 1 (Matt Frost)

• Magnetic coupling

• Hall probe

Prototype 2 (Will Kim)

• Mechanical coupling

• OPTEK sensor

Designed to be a high quality (Q > 1000) Open Source Hardware Kit (e.g. Adafruit). Jupyter

Notebook interface with Raspberry Pi or Arduino via Python. Hot Topic at Third Conference on

Laboratory Instruction Beyond the First Year in Baltimore - Targeting Student Design and Mod-

eling Skills using Coupled Oscillators, Kim, Frosst, Cai and McLean. DESIGN EXPERIMENT

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PHYS250 Open Source Hardware Kits e.g. AdaFruit