Clicker Use in upper-level physics courses

Michael DubsonDept. of Physics

U. Colorado at Bouldermichael.dubson@colorado.edu

Please pick up a clicker.And please sit near front.

Physics Education Research University of Colorado at Boulder

• Physics faculty:Physics faculty: Noah FinkelsteinNoah FinkelsteinSteven PollockSteven PollockMichael DubsonMichael DubsonKathy PerkinsKathy PerkinsCarl Wieman Carl Wieman

• Postdocs: Postdocs: Stephanie ChasteenStephanie ChasteenLaurel MayhewLaurel MayhewSam McKaganSam McKaganArchie PaulsonArchie Paulson

Ph. D. students:Charles BailyNoah PodolefskyChandra TurpenLauren Kost

School of Ed collaborators:Prof. Valerie OteroBud TalbottKara Gray

http:// per.colorado.edu

Novice vs. Expert:

CU Physics course reforms since 1997:

• Peer Instruction

• Conceptual exams

• Interactive Homework

• Helproom

• Washington Tutorials/ undergrad TA's

• Pre/post tests

• Team-teaching

•All freshmen classes and Physics III transformed•Strong efforts in upper-level Math Methods, QM, E&M, Stat Mech

At U.Colorado Boulder, 70% of undergrads (17,000) use clickers in >100 courses in 15 departments.

A Difficult Question:

What Letter Am I thinking of?

A B C D E

Confer with your neighbors, then vote.

Worse Concept Tests• merely test recall• blind application of formula/recipe• many numbers

Better Concept Tests• qualitative understanding • students provide next step in the lecture• use familiar skill in unfamiliar context• support a learning goal

What happens during my QM1 or StatMech class ?

• 50 min lecture: Clicker question running when students enter ~ 30 min lecture in 10 min chucks

~ 20 min on 3 or 4 concept tests, discussion, demos

• Group discussion enforced with clicker groups• Mostly traditional (difficult) homeworks• Exams mix of computational and qualitative/conceptual • Formula sheet on exams.

A ball rolls back and forth in a valley. Eventually, the ball slows and stops. We never observe the reverse.Consider :•Conservation of energy (1st Law of Thermo)•Entropy of an isolated system increases (2nd Law)•Conservation of momentum

The reverse process never occurs because this would violate: A) 2nd Law only B) All three C) Cons. of energy & cons. of mom.D) Cons.of energy & 2ndLawE) Cons.of mom. & 2ndLaw

Giving the answer STOPS discussion

• Elicit student reasoning, before giving answer.• Understanding why wrong answers are wrong is as

important as why right answers are right.• Value reasoning above answer. A right answer

without a reason is useless. A wrong answer for a good reason has value.

Student must be convinced that•understanding = high exam score.•memorizing answers to specific questions

= low exam score.

5 charges, q, are arranged in a regular pentagon, as shown. What is the E field at the center?

A) ZeroB) Non-zeroC) Really need trig and a calculator to decide

q

q

qq

q

2.5

A plane wave, incident from the left, tunnels through potential barrier. E-eigenstate solution has A) the same wavelength on both sides of the barrierB) a smaller wavelength after tunnelingC) a larger wavelength after tunneling

EV

x

Re[

same

smaller

larger

50% answered (B) due to misuse of a rule: in deeper parts of well V(x), eigenstates have shorter wavelength (bigger KE) and smaller amplitude (shorter dwell time)

Students tend to ...• remember the first thing told • over-generalize

So.. Be careful how you introduce a topic.

Design CTs to test limits of validity.

Griffiths, Intro to QM 2nd Ed.

The ground state energy of a finite square well is ______ than the grd state energy the infinite square well with the same width a

A) the same B) higher C) lower

a

?

a

How do you make up good Concept Tests?

• Key points in lecture make with CT

Don't tell. Ask.

• What is my learning goal? Test with CT

• Listen in on student-student conversations in the Helproom.

Physics HelpRoom• All TA's and faculty hold office hours here.• Hours staggered, room is always staffed.

What is ?

A)ZeroB) 1 C) 2

D) (0)E) (x2 – x1)

1 2 1 2f (x , x ) dx (x x ) (x x )

Can the wavefunction (x,t) describing an arbitrary

physical state always be written in the form

where n(x) and En is solution of ?

A) Yes B) No

)/exp()(),( tiExtx nn

n n nH (x) E (x)

Thanks to Chandralekha Singh, U. Pittsburg

Peer Instruction/ ConcepTests,

Eric Mazur, Harvard 1997

Crouch and Mazur,

Am. J. Phys. 69, 970 (2001)

Also see:

Beatty et. al., Am. J. Phys. 74, 31 (2006)

Reay et al., Am. J. Phys. 73, 554 (2005)  

Poor use of clickers.. • solely for taking attendance

• for quizzes or high-stakes testing

• only occasionally, or at set times

Better use of clickers.. • Integrated into lecture, frequent• Require peer instruction• Mix of difficulty: very easy to very difficult CTs• Generous credit for any answer• Low grade impact (~2%)

Problem: Good CTs lead to good class discussion, eats into lecture time

Solution:

Stop complaining.

Avoid long derivations in lecture:• Create HW problems that test knowledge of derivations.• Detailed derivations online or in assigned reading.• Derive in class only if making point testable with CTs

Golden Rule of Lecture.It's OK to lecture less,

because they're not listening anyway.

(Scribe mode listening)

Use Concept Tests & Peer Instruction :

Active learning better than passive learning

Physics students are very busy (and human):

They have extensive training in :• Symbol manipulation• Getting the right answer• Effort-minimization• Survival

They have little training in:• Sense-making• Articulation of ideas• Prioritization of knowledge• Group work• Solving vague problems

Another Golden Rule of Lecture.Emphasize qualitative reasoning and

conceptual understanding.

• in lecture

• on homeworks

• on exams

It doesn't matter if they can compute the acceleration, if they don't know what acceleration is.

because students can misinterpret what we say.

Two-way conversations with students are vital,

“Pearls Before Swine” by Stephan Pastis, 2002.

Concept Test

An unopened bottle of Champagne, equipped with a pressure gauge, has been sitting on the shelf for a long time. The bottle is given a brief, vigorous shake. What happens to the pressure in the bottle? (A brief shake will raise the temperature < 0.01o C)

A) The pressure remains unchanged

B) The pressure falls significantly.

C) The pressure rises significantly.

Conclusions

• Students learn by doing, not by listening

• Concept Tests and Peer Instruction can work well in upper-division courses.

• Libraries of upper-division CTs coming soon at..

http:// per.colorado.edu

(Please return your clicker.)

Appedices:

• Following slides for Q/A use.

Standardized Pre/post tests: Physics1 Mechanics: FCI, FMCE, Physics2 E&M: BEMA

Need some assessment of success/failure.

BEMA (matched) (CU scoring) Fa04g(ave)=.44, N=331

0

5

10

15

20

25

30

35

40

45

50

0 6 12 18 24 30 36 42 48 54 60 66 72 78 84 90 96

Score (%) (CU scoring)

# o

f stu

den

ts

Pre (ave=26)

Post (ave=59)

LA pre

LA post

TA post

TA pre

CU upp div post

1120 post

NCSU tradpost

NCSU honor& CMU tradpost

CMU M&Ipost

CMU uppdiv post

Expert / Novice views of problem solving

( Kathleen Harper, Ohio State, Physics Teacher April 2006)

• Problem solving is ..

a process • Problem solving begins with …

qualitative analysis • Problem classification is based on ..

deep structure • Tools include..

graphs, diagrams, limits, conservation laws, etc

"the equation"

/ a recall task

/ hunt for "the equation"

/ surface features

Concept Test /Peer Instruction

How many liters of Scotch Whiskey are stored in Scotland?

Hints: Scotch is aged ~10 years before sale. All Scotch is made in Scotland.

A) 300,000 B) 3 million

C) 30 million D) 300 million

E) 3 billion

The Message: Answer NOT important.

Strategy is the goal.

Strategy:• Store as much as you can sell.• Sales depends on population and average demand.

Student must be convinced that•understanding strategies = high exam score.•memorizing answers to specific questions

= low exam score.

Quantitative vs. Qualitative Problems

• Quantitative:In the circuit, V = 25V, R1 = R2 =

10, R3 = R4 = R5 = 15, R6 = 50. What is the current through resistor R3?

Qualitative.When R6 increases, the current through R3 _______.A) Increases B) decreases C) remains constant?

Washington Tutorials replacing traditional TA-led recitations

Success required:• Dedicated space / furniture• Lab equipment• Undergraduate TA's• Proper training of staff

The Golden Rules of Lecturing:

If they learned something, but they leave hating the subject, you have failed.

• Morale is vital:

Talk to/listen to students, especially during office hours.

Rule 1.

Survey Q12. How useful for your learning is the addition of clicker questions compared to pure

lecture with no clicker questions?

0%5%

10%15%20%25%30%35%40%45%50%

clickers much more

useful

clickers more useful

same lecture more useful

lecture much more

useful

Student feedback very positive:2 out of 30 students objected to class time spent on Concept

TestsEnthusiastic response from others:• More than half the students listed Concept Tests as the single most

effective aspect of course.• "Concepts emphasized – really helpful to get beyond the math"• "Please teach quantum, no one understands it"

Reform sustainable?In the 6 semesters since reform of Stat Mech,•1/2 professors have used Concept Tests•1/2 professors have taught traditional course.