Clicker Use
in upper-level physics courses
Michael Dubson
Dept. of Physics
U. Colorado at Boulder
michael.dubson@colorado.edu
Please pick up a clicker.
And please sit near front.
Physics Education Research
University of Colorado at Boulder
• Physics faculty:
Noah Finkelstein
Steven Pollock
Michael Dubson
Kathy Perkins
Carl Wieman
• Postdocs:
Stephanie Chasteen
Laurel Mayhew
Sam McKagan
Archie Paulson
Ph. D. students:
Charles Baily
Noah Podolefsky
Chandra Turpen
Lauren Kost
School of Ed collaborators:
Prof. Valerie Otero
Bud Talbott
Kara Gray
http:// per.colorado.edu
Novice vs. Expert:
CU Physics course reforms since 1997:
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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
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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
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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 & 2ndLaw
E) 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.
2.5
5 charges, q, are arranged in a regular
pentagon, as shown.
What is the E field at the center?
q
q
q
q
q
A) Zero
B) Non-zero
C) Really need trig and a calculator to
decide
A plane wave, incident from the left, tunnels through
potential barrier. E-eigenstate solution has
A) the same wavelength on both sides of the barrier
V
B) a smaller wavelength after tunneling
C) a larger wavelength after tunneling
Re[y]
l
same l
x
l
l
smaller l
larger l
E
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
f (x1 , x 2 )   dx d(x  x1 )d(x  x 2 ) ?
A)Zero
B) 1
C) 2
D) d(0)
E) d(x2 – x1)
Can the wavefunction Y(x,t) describing an arbitrary
physical state always be written in the form
Y( x, t )  y n ( x) exp( iEn t / )
where yn(x) and En is solution of Ĥ yn (x)  En yn (x)?
A) Yes
Thanks to Chandralekha Singh, U. Pittsburg
B) No
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..
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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.
Two-way conversations with students are vital,
because students can misinterpret what we say.
“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.
Need some assessment of success/failure.
Standardized Pre/post tests:
Physics1 Mechanics: FCI, FMCE,
Physics2 E&M: BEMA
BEMA (matched) (CU scoring) Fa04
g(ave)=.44, N=331
CU upp LA 1120
div post pre post
50
LA
TA
post pre
TA
post
45
# of students
40
35
30
25
20
15
10
5
0
0
6
12
18
24
30
36
42
48
54
60
66
72
78
84
90
Score (%) (CU scoring)
Pre (ave=26)
Post (ave=59)
NCSU trad
post
NCSU honor
& CMU trad
post
CMU M&I
post
CMU upp
div post
96
Expert / Novice
views of problem solving
( Kathleen Harper, Ohio State, Physics Teacher April 2006)
• Problem solving is ..
a process / a recall task
• Problem solving begins with …
qualitative analysis / hunt for "the equation"
• Problem classification is based on ..
deep structure / surface features
• Tools include..
graphs, diagrams, limits, conservation laws, etc
"the equation"
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
C) 30 million
E) 3 billion
B) 3 million
D) 300 million
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:
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Dedicated space / furniture
Lab equipment
Undergraduate TA's
Proper training of staff
The Golden Rules of Lecturing:
Rule 1.
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.
Survey Q12. How useful for your learning is the
addition of clicker questions compared to pure
lecture with no clicker questions?
50%
45%
40%
35%
30%
25%
20%
15%
10%
5%
0%
clickers
clickers
much more more useful
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
Tests
Enthusiastic 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.