Instructional Laboratory for Experimental Training (INLET)

dB-SERC lunch talk, August 3, 2015

Brian R. D’UrsoAssistant Professor of Physics and Astronomy

Oak Ridge National LaboratoryMeasurement Science and Systems Engineering Division

University of PittsburghSchool of Arts and SciencesDepartment of Physics and Astronomy

University of PittsburghDepartment of Physics and Astronomy

Goals of Advanced Labs in Physics

1. To demonstrate physics principles which students have been taught in lecture classes

2. To teach students research techniques as preparation for a possible future career in research.

3. To help students learn to think like a physicist

4. To attract students to STEM fields by helping them experience the research process

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University of PittsburghDepartment of Physics and Astronomy

Problems with Advanced Labs in Physics

1. No opportunity for students to design experiments and explore outcomes

2. Resistance to modernizing the equipment• Cost, effort, no clear guidelines or best practices

3. Modern equipment is often too automated• Commonly use closed and proprietary “black boxes”

• Student just push a button to get the answer

4. Result:• Labs are outdated

• Equipment is primitive compared to technology in daily use

• Student may be discouraged from STEM fields by a misrepresentation of the state of experimental research

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University of PittsburghDepartment of Physics and Astronomy

Proposed Lab Reform Guidelines

1. Use research-grade equipment and techniques:• Don’t “dumb down” with the idea of getting students to learn more by

slowing them down• For example, don’t make students turn knobs and record data by hand if that

is not how it would be done in a research laboratory

2. Standardize equipment and software across experiments and classes:• Researchers learn to trust certain pieces of equipment, and re-use that

equipment they understand in a variety of situations• Students should leverage what they learn from one class to another and build

up a coherent set of tools to use

3. No “black boxes”:• Tempting to purchase special-purpose data acquisition cards or custom

components made just for instruction• Hard to understand exactly what they do• Hard or impossible to modify

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University of PittsburghDepartment of Physics and Astronomy

Proposed Lab Reform Guidelines

4. Have students debug by following signals through the experiment:• Trace signals (optical, electrical, etc.) through the experiment and

describe how they change to get an understanding of how the experiment functions

• Even better: allow students to figure out how to connect parts of experiments

5. Encourage exploration:• All parts of experiments should be alterable by students

• Policies, e.g. ask open-ended questions in laboratory exercises and give grade incentives for exploration

6. Encourage collaborative learning: • Students should be encouraged to work in teams and to complement

each others' efforts 6

University of PittsburghDepartment of Physics and Astronomy

Proposed Lab Reform Implementation

1. Arduino microcontroller boards:• Inexpensive, open source platform on which to build

instruments for data acquisition and instrument control

• Programming these boards is within the ability of undergraduate students

2. Analog and digital interface circuits:• Most experiments require some amount of custom

circuitry

• Build these circuits on solderless breadboards so students can manipulate the circuits and explore their function

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University of PittsburghDepartment of Physics and Astronomy

Proposed Lab Reform Implementation

3. Python and Pythics:• Research experiments are computer-controlled, so instruction

laboratory experiments should be controlled in the same way

• Use Python and other open source components

4. Scaffolding:• Reformed labs will guide students to explore the experiments

with open-ended questions

• Guide students through function (and perhaps setup)

• Ask students to use the apparatus to gather data, first with simple measurements and then gradually building to the full complexity of the experiments

• Provide goals and questions to answer rather than a recipe for what to do

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University of PittsburghDepartment of Physics and Astronomy

Implementation Details: Interface Circuits

• Use solderless breadboards for special-purpose circuits when possible

• Easy for students to change• Instructors may have to re-build circuit after

each lab• Need to build in

protection for valuable or sensitive equipment, since errors are unavoidable (and part of the learning process)

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University of PittsburghDepartment of Physics and Astronomy

Implementation Details: Arduino

• “Arduino is an open-source electronics platform based on easy-to-use hardware and software. It's intended for anyone making interactive projects.”

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Arduino DUE

University of PittsburghDepartment of Physics and Astronomy

Implementation Details: Arduino Shields

• Add-on circuit boards (shields) interface Arduino to outside signals• Many shields (e.g. motor controller, cell phone interface, WiFi) are

commercially available• We design and produce our own shields for interfacing physics

experiments

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Analog I/O Digital I/O High-Speed Counter

University of PittsburghDepartment of Physics and Astronomy

Implementation Details: Pythics and Python

• Pythics: a tool for creating simple interactive interfaces to laboratory instruments and numerical simulations.

• Pythics displays GUI and links GUI objects to Python code

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GUI Python Code

University of PittsburghDepartment of Physics and Astronomy

D’Urso Group Arduino Instruments

oscilloscope

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spectrum analyzer

lock-in amplifier

network analyzer

Arduino DUE

University of PittsburghDepartment of Physics and Astronomy

Lab Handouts and Experiment Structure

What should a lab handout do?• Provide historical background and summarize the relevant physics

– Students don’t have time to do this on their own

• Explain what the equipment does and how it works– Hard to do with “black boxes”, open equipment is a must

• Explain the idea of the experiment and the role of the equipment• Provide measurement goals and questions to resolve• Let students figure out what procedure to use and to argue that it is reasonable• Provide some “tips and tricks” to help students avoid common pitfalls

Lab instructor must provide support in lab• Students explain what they are trying to do and what is/isn’t working

(don’t accept “it just doesn’t work”)• Give as much help as is needed to keep students progressing• Students also encouraged to discuss with other students

who have already completed the experiment

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University of PittsburghDepartment of Physics and Astronomy

Lab Reports (inspired by Cary Moskovitz, Duke)• What is the purpose of lab reports?

– Student view: to get a good grade– Practice for technical writing?– What is the purpose of an introduction

or repeating a given procedure “in their own words”?

• Who is the audience?– Student view: the instructor– Often made up: tell students to write for other students, for a friend, for ???

• What really makes sense?– Write for the instructor– Skip introduction, include procedure only if students have to develop or modify it– Writing should argue that the procedure, results, and analysis

support their conclusions

• Opportunity:– Give students the option to revise their lab reports to regain 50% of lost credit

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University of PittsburghDepartment of Physics and Astronomy

Example 1: Mossbauer Spectroscopy

Original experiment:• Shows that the Mossbauer shift can be measured using a shift in

gamma ray energies due to the Doppler effect• Uses legacy hardware and software are no longer supported,

unalterable, and not fully documented

Redesigned experiment:• Study the same physics• Use Arduino as MCA and to

coordinate data acquisition and absorber movement.

• Use Pythics/Python to control the experiment and display data.

• All new parts can be easily modified 17

University of PittsburghDepartment of Physics and Astronomy

Example 2: Acoustical Cavity Modes

Original experiment:• Acoustical cavity is excited by a speaker which is driven by a frequency synthesizer • Students adjust the driving frequency and measure the amplitude of the response on

an oscilloscope• A poor experimental approach: sensitive to external noise, insensitive to the phase

response (misses real physics!)

Redesigned experiment:• Keep synthesizer to drive speaker

and oscilloscope for observing output• Use Arduino-based lock-in amplifier• Use Pythics/Python to control the

experiment and display data• Shows proper experimental technique

and more physics• Similar approach can be used to reform

two other experiments

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University of PittsburghDepartment of Physics and Astronomy

Final Reports or Final Projects

• Traditional: Final Reports“…each student will submit a research paper. The paper will be based on a Nobel Prize physics experiment. Their work will be described in a short paper (8-15 pages double spaced) which emphasizes the measurement and physics aspects of the topic studied. It should have an introduction and a conclusion with some theoretical discussion.”

• Alternative: Final Projects– Students choose an experiment to explore further

or apply to a new situation– Students write a paper that includes:

• Background research (beyond handout)

• A description of any equipment or software modifications

• A detailed modified procedure

• Results with thorough analysis to demonstrate changes

– Provides an opportunity for a more authentic research experience

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University of PittsburghDepartment of Physics and Astronomy

Expected Advantages and Disadvantages

Pros• More authentic research experience

– Attract students to STEM fields– Prepare students for research

• Relatively low equipment cost• Enables experimental final projects

Cons• More time exploring means less time for getting experiments

done• Things are going to break, instructors need to put everything

back in order for each group• Instructor needs to engage with students during labs, not just

observe (may not be suitable for TAs alone) 20

University of PittsburghDepartment of Physics and Astronomy

Assessment

Questions:• Are students are more likely to value the reformed labs and if so, why?• Do the reformed labs influence students’ attitude towards the labs, STEM fields, and

research?• Do the reformed labs change the students’ performance?Methods:• First year: control group• Written and oral quizzes probing the depth of their understanding of lab content• After each lab, ask students to write a typed reflective essay on what they learned

from the lab• Give students an attitude-based survey, such as E-LAS • At the end of the semester, ask students to write a reflective essay on two labs they

liked the most and/or learned most from and why they feel that way. • Conduct audio-recorded think-aloud interviews with individual students in which they

will be asked questions about their views on the effectiveness of the traditional and reformed labs– Which aspects were effective and what can be improved further? – Incorporate feedback from the students in future years

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University of PittsburghDepartment of Physics and Astronomy

Acknowledgements

This project funded by a dB-SERC course transformation award

NSF-funded project expected to be awarded soon, grant written and prepared with support from C. Singh and dB-SERC

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