Physics Laboratory Instruction Challenges and Triumphs Duane Deardorff

Physics Laboratory Instruction: Challenges and Triumphs Duane Deardorff, Ph. D Dept. of Physics and Astronomy The University of North Carolina at Chapel Hill Lecture at Universidad San Francisco de Quito October 21, 2015

Outline �My role at UNC-CH �Motivation for reforming courses �Overview of lab courses �SCALE-UP �Lecture/Studio �Laboratory performance assessment �Higher level lab courses �Questions and discussion

My role at UNC-CH �Joined faculty in January 2000 (16 years ago) �Director of Undergraduate Laboratories �Responsible for administration of all teaching labs � 10 courses, ~3000 students per year �Lecturer �I teach 1 or 2 classes each year, mostly introductory physics �Have now taught all of the intro physics courses at least once (including lab sections)

Collaborators �Laurie Mc. Neil, Professor at UNC-CH �Alice Churukian, Senior Lecturer at UNC-CH �David Smith, STEM lecturer at UNC-CH �Colin Wallace, STEM lecturer at UNC-CH �Bob Beichner, Ph. D advisor at NCSU

I hear, and I forget. I see, and I remember. I do, and I understand. - Confucius Students understand more when they are actively involved in the learning process.

Results from a study of 6000 physics students R. Hake, “…A six-thousand-student survey…” AJP 66, 64 -74 (1998). – Hake AJP 1998

Effect sizes by discipline. Scott Freeman et al. PNAS 2014; 111: 8410 -8415 © 2014 by National Academy of Sciences

http: //www. aapt. org/Resources/upload/Lab. Guidlines. Document_EBendorsed_nov 10. pdf

Laboratory Courses at UNC-CH �ASTR 101 L (Descriptive Astronomy) – 1000/yr �PHYS 114 (Physics I for Life Sciences) – 800/yr �PHYS 115 (Physics II for Life Sciences) – 600/yr �PHYS 118 (University Physics I) – 400/yr �PHYS 119 (University Physics II) – 250/yr �PHYS 281 L (Experimental Techniques) – 60/yr �PHYS 331 L (Numerical Techniques) – 40/yr �PHYS 351 L/352 L (Electronics) – 60/yr �PHYS 481 L/482 L (Advanced Lab) – 30/yr

Timeline for reforming intro physics courses at UNC-CH �Fall 2010: First SCALE-UP class (1 section of PHYS 116) �Spring 2011 – Spring 2014: 2 SCALE-UP sections �Physics 116 (opposite 2 or 3 traditional sections) �Physics 117 (opposite 1 traditional section) �Fall 2014: First Lecture/Studios of PHYS 114, 118 �Spring 2015: All 4 intro courses taught in Lecture/Studio format

Traditional Format �Students meet for 3 lectures (50 min. each), MWF �Led by professor(s) �Includes “clicker” questions and demonstrations �Students attend 1 lab section (110 min. each) �Led by graduate and undergraduate TAs (1 per 25) � 9 lab experiments with 2 full and 7 short reports �Recitation or Supplemental Instruction (SI) session �Guidance and practice with problem solving �Homework using Mastering. Physics or Web. Assign

Implementing SCALE-UP in Physics at UNC-CH Dept. of Physics and Astronomy The University of North Carolina at Chapel Hill Progress report for 2012, prepared by Duane Deardorff and Alice Churukian

What is SCALE-UP? Student-Centered Active Learning Environment for Undergraduate Programs �Pioneered by Bob Beichner at NCSU �Integrated lecture, lab, and recitation �Class meets 2 hours each MWF �Students work in groups of 3 at round tables �Utilizes research-based teaching methods that have been demonstrated to yield higher learning gains compared with traditional lecturing

Before and after photos

Costs Equip. costs shared by P&A, CFE, College, grants � Demolition, wiring, painting: ~$15 k � New furniture (5 tables, 47 chairs, 1 teaching station): ~$25 k � A/V equipment (2 projectors, screens, doc cam, controller): ~$25 k � New lab equipment to supplement existing equipment: ~$35 k �Total ~$100 k Cost savings from teaching perspective � Less TA time (1. 5 TAs instead of 2. 5 TAs for traditional) ~$8 k/course � More faculty time for 45 -student class (versus ~75 students in trad. ) � This is especially true when a second faculty member is hired for training.

Use of remodeled room Fall 2010 �Phys 116: Calc-based Gen. Physics I �Phys 54: Physics of Movies �Phys 521: Quantum Mechanics �Phys 861: Nuclear Physics �Physics 116 recitations �Astr 101 L: Descriptive Astronomy �Office hours, group meetings Spring 2011 �Phys 116: Calc-based Gen. Physics I �Phys 117: Calc-based Gen. Physics II �Phys 331: Numerical Techniques �Phys 410: Teaching & Learning Physics �Math 410: Teaching & Learning Math �Phys 116 & 117 recitations �Office hours, group meetings

Faculty interest and support �The remodeled room is very popular! �Faculty are supportive in theory more than practice. �It has been challenging to find faculty willing to teach Physics 116 or 117 SCALE-UP (too much time & effort). �This project has sparked interest and dialogue about teaching (which generally takes a back-seat roll to research).

Student interest and feedback �Most students (~80%) prefer SCALE-UP over traditional format, but nearly all would like to have more lecture time. �Top students (including physics majors) express frustration that working in groups holds them back, even if they learn the concepts better by teaching their peers. �The SCALE-UP format works well for students who learn by doing. Most students like group work and hands-on activities. �Class attendance is important, and falling asleep in class is not really an option!

SCALE-UP versus Traditional �Assessment performed by Physics dept. and CFE �Similar performance between sections � Mid-term exams � Lab exams � Final Exams �“First do no harm!” – mission accomplished �SCALE-UP students performed better on concept surveys

Conceptual survey results for Physics 116 Normalized Gain - FCI 60 50 40 Traditional 30 SCALE-UP 20 10 0 Fall 2010 Spring 2011 Fall 2011 Spring 2012 Fall 2012

Conceptual survey results for Physics 117 Normalized Gain 60 50 40 Traditional 30 SCALE-UP 20 10 0 Spring 2011 Fall 2011 Spring 2012 Fall 2012

SCALE-UP students were more likely to: �Identify class attendance, conceptual questions discussed in class, and examples worked in class as important to furthering their understanding of course materials. �Ask a question or make a comment that contributed to class discussion. �Agree that students in this class help one another. �Disagree that it is possible to do well in this course without attending class regularly. �Disagree that their coursework emphasized memorizing factors, ideas and methods. �Feel that this class was less challenging than other classes.

Challenges �Short time to implement – forced to develop curriculum in real time without release time. �Equipment sharing adds to Lab Manager workload. �Student registration is difficult since lecture, lab, and recitation could not be linked by Registrar. Department permission to register is time consuming. �Common exams for all sections of Physics 116 and 117 have been implemented since 2011, and this has unified the course curriculum and learning objectives.

Lessons Learned • SCALE-UP students generally perform as well or better on classroom assessments (exams) compared with students in the traditional course sections. • SCALE-UP students demonstrate higher learning gains on conceptual surveys administered pre/post instruction. • Student performance on lab activities, reports, and lab exams are similar for SCALE-UP and traditional sections (no significant overall differences have been observed due to relatively high variability in these measures). • Drop-out (or retention) rates for the SCALE-UP classes have generally been similar to the traditional sections. • Students generally prefer the SCALE-UP format over traditional lecture/lab/recitation. • Teaching in the SCALE-UP format requires more preparation and flexibility, but it can be more rewarding.

Lecture/Studio Format �Students meet for 2 lectures (50 min. each), MW �Led by professor(s) �Includes “clicker” questions and demonstrations �Students attend 2 studio sections (110 min. each), MW �Led by graduate and undergraduate TAs (1 per 25) �Experiments, simulations, and problem-solving �Exams or optional review sessions on Fridays �Homework using Mastering. Physics or Web. Assign As of 2015, all 4 introductory physics courses at UNC are now taught in this format. We are currently reviewing the evaluation data to assess how we did this past year.

Physics Laboratory Performance Assessment at UNC-CH Contributed talk BG 02 presented Sunday, January 4, 2015 at the Winter AAPT meeting, San Diego, CA Duane L. Deardorff Dir. of Undergraduate Laboratories in Physics and Astronomy at The University of North Carolina at Chapel Hill www. physics. unc. edu/~deardorf www. physics. unc. edu/labs

Overview �For the past 13 years, an individual, hands-on lab exam has been administered near the end of our introductory physics laboratory courses: �Phys 24 & 25 (algebra-based for bio, pre-med majors) Combined: N 500 students per semester �Phys 26 & 27 (calc-based for physics, comp sci, etc. ) Combined: N 200 students per semester �Labs are mostly traditional, experimental verification. �Lab exam counts for 20% of total lab score, which is 25% of course grade. This is roughly equivalent to 2 lab report scores since there are 9 labs/course. �A sample lab exam for each course (with answers) is on lab website so students know what to expect and can practice with equipment in Tutorial Center.

Why have a lab exam? �Lab reports generally do not assess lab skills. �Individual lab practicum provides incentive for all students to learn lab skills (not just hands-on learners). �Help ensure that TAs teach proper methodology. �To discover weak areas of curriculum and TA training that need improvement. �Can be used as a proficiency exam for students trying to test out of lab. �To improve discrimination of lab scores. (Some faculty complain that lab scores are too high, have narrow distribution, and are not consistent with course exam scores. )

Lab exam learning objectives ·Correctly use lab equipment to measure physical quantities. ·Correctly report each measurement with label, accurate value, reasonable uncertainty, sig. figs. , and proper unit. ·Analyze experimental results and write a valid conclusion. ·Identify and explain choice of lab procedures used. ·Apply familiar experimental techniques to new situations. ·Determine final result and uncertainty from given data. ·Identify the primary source of error in an experiment. ·Properly construct graphs and interpret results. ·Design a simple experiment to measure a desired quantity.

Format �Students work individually on written and hands-on exercises that are similar to tasks they (should) have already done in earlier labs. �Open-book, open notes: students are allowed to use any resources except other people. �The exams are designed to require about 1 hour, but students are allowed 2 hours (normal lab period) �Sample lab exams with answers are provided on lab website. Equipment is available in Physics Tutorial Center for students to practice and get help. �Lab exams are modified only slightly from semester to semester (usually only 1 or 2 questions are changed. ) �Students do not get to keep lab exam papers.

Instructions to Students Instructions: Work individually to complete each exercise to the best of your ability, show all your work, and clearly explain your answers in the spaces provided or on the back of these papers. Be sure to record all measurements (in SI units) and show all calculations. For items that require a numerical result, write your answer as you would for a formal lab report, including a meaningful label to identify a value. Your answer will be graded based on the accuracy of your result and proper reporting of uncertainty, significant figures, and units. Once the lab exam begins, you are not permitted to receive any assistance from your TA or other students. However, you may use your lab manual, graded lab reports, notes, and textbook as resources for this exam. The questions may be answered in any order, so adjust your work according to the availability of the lab equipment. Honor Pledge: All work presented here is my own. _____

Lab exam content - Mechanics Ranked roughly according to question weighting: 1. 2. 3. 4. 5. 6. 7. 8. 9. Use photogates to measure accel. of glider on air track Measure density of nickel coins. Are they pure nickel? Given time and distance data, find acceleration and xo. Use Vernier caliper to find radius of a steel ball Report best estimate of length of hall from 6 measurements Determine mass of rotating object from graphical results Calculate error from flag on air track glider rotated 20° Accuracy and precision of a simple pendulum How to report sin(80° ± 1°)?

Lab exam content – E&M Ranked roughly according to question weighting: 1. 2. 3. 4. 5. 6. 7. 8. 9. Connect circuit shown and measure currents with DMM. Use oscilloscope to measure time constant for RC circuit. Given a trace, find Vpp, Vrms, and frequency of signal. Calculate RT for 2 resistors (with 5% tolerance) in parallel Find n for block shown with refracted ray passing through. Given a converging lens, estimate its focal length. Given radioactive decay data, find half-life. Sketch graph of I vs V for light bulb that is non-ohmic. Given ammeter reading, report current value and uncert.

Grading A detailed rubric was developed on Excel for scoring by hand or by computer �Grading takes ~5 min/student �Objective grading except for explanations of procedures �Measured values are generally considered accurate if they are within ± 2 U of the median expert value, where U is the combined standard uncertainty (RSS of Type A and Type B components). �Uncertainty values are generally acceptable up to 5*U �Good reliability (avg. difference between graders is 2%)

Grading – Target Weights Component Weight Accurate values 40% Units 15% Uncertainty 15% Significant figures 10% Labels 5% Procedures 10% Explanations 5% Total = 100%

Grading – Typical Results Component Accurate values Units Uncertainty Significant figures Labels Procedures Explanations Weight 40% 15% 10% 5% Avg. Score 54% 79% 35% 48% 67% 85% 66%

Historical Physics Lab Exam Averages 100 90 80 70 60 P 104 50 P 105 40 P 116 P 117 30 20 10 0 Spring 2011 Fall 2011 Spring 2012 Fall 2012 Spring 2013 Fall 2013

Historical Trends �Average scores vary from semester to semester, but are mostly constant over time: ~65% (similar to course exam scores) �Spread of scores (SD) each semester is consistent. ~15% �Slight decline in exam performance in recent years, not sure why. Apparently students are not cheating much from old exams! �Exam is robust even without significant changes from year to year.

Typical results (Physics 105, Spring 2012) Conclusion: Scores do not increase or decrease throughout the week.

Correlation analysis for Phys 24 Lab exam scores vs: R Lab report scores 0. 3 - 0. 4 Course exam average 0. 5 - 0. 6 Web. Assign homework 0. 4 - 0. 5 Class participation 0. 2 - 0. 3 Conclusion: Lab exam does not duplicate lab report scoring, but it does correlate well with course exams. (Correlation between exam scores is ~0. 5)

Conclusions �The lab exam provides a rich set of research data. �Lab exam and lab reports are different assessments – together they give a more valid measure of a student’s achievement. � 90% of students responded that they felt the exam was fair - evidence of good content validity �Motivates students (and TAs) to learn lab skills �Opportunity to practice is important for student learning �Faculty are generally pleased with lab exam and scores that are more consistent with course performance �Student performance is not nearly as good as we would like for our students to achieve. We still have much work to do! �Not surprisingly, performance depends on training and experience in class.

PHYS 281 L: Experimental Techniques in Physics �Measuring the speed of light by two different methods �Measuring “big G and little g” with Cavendish balance and Kater’s pendulum �Michelson interferometer �Photoelectric effect; measurement of Planck’s constant �Charge-to-mass ratio of electrons �Millikan oil drop �The Rydberg constant from hydrogen spectrum �Energies and attenuation coefficient of gamma-rays �Muon half-life from cosmic rays �Chaotic pendulum analysis with Lab. VIEW

PHYS 481 L: Advanced Laboratory for Physics �Mechanical properties of materials �Superconductivity �Fiber optics �Hall effect �Spectroscopy �Faraday rotation of light �Optical absorption �X-ray diffraction �Ellipsometry

Questions and Discussion �What are the primary issues with your physics labs? �What is working well? �What problems need to be addressed? �What (if any) changes do you expect to make in your physics lab courses? �Other questions?