Physics and webCT
Craig Ogilvie, Department of Physics and Astronomy
cogilvie@iastate.edu
 Improving introductory physics at Iowa State
– Phys 111, 112, 221 and 222, enrollment 1300/semester
 Concentrate on Phys 222
– Online assignments
– Discussion board
– Lecture notes
– misc., mygrades, skill profile,….
Phys 111, 112, 221 and 222
 Improving
courses, ongoing :)
– active-learning in lectures, small group discussions
– problem-solving emphasis
– group project, apply physics-modeling to industrial,
engineering system
 Use of webCT, online assignments
– reduce grading for TAs
» frees time to work with students (see above)
» Or reduces number of TAs =>costs
– improve the feedback to students on their work
Online Assignments
 Four
–
–
–
–
types of assignments
pre-lecture ‘reading’, simple questions to encourage
text-book usage
pre-labs, questions to prepare for lab-tasks
conceptual assignment
» once per week
quantitative homework
» once per week
Mechanics
 Multiple-choice
questions written in Respondus
 Calculated questions, numerical grading engine webCT
– if no graphics or equations, write directly in webCT
– otherwise Respondus =>upload to webCT =>convert
Pre-lecture
Pre-lab
Concept
Quantitative
390
200
650
620
1) Question sets, students receive different questions
2) Developing mySQL database to store, select questions
ready by end of Spring 04
Typical Quantitative Question
You are designing a circuit that has a very long,
essentially infinite, wire which has an upwards current
that increases at a rate of di/dt, where di/dt > 0. Also on
your circuit, but not connected to the long wire, is a
square loop (length of each side is “a” and whose closest
edge is a distance d from the wire).
The changing current in the long wire will induce an emf
in the square loop. This is a common problem in many
circuits. What is the induced emf in the square loop, and
which direction would the induced current flow?
1) solution requires student to develop ½ page of algebra
2) assesses quantitative skill, ability to combine several ideas
Multiple-Choice Answers Available
A
B
C
D
clockwise
clockwise
clockwise
clockwise
E
counter-clockwise
counter-clockwise
F
G
H
counter-clockwise
counter-clockwise
1) Not possible to guess answer
2) Wrong answers deliberately chosen for common mistakes
3) Partial credit awarded
Submission Patterns
 More
than 90% students submit each assignment
 60% of students submit within two hours of deadline
score (%)
Sample of one assignment (one of the harder ones)
70
60
50
40
30
20
10
0
0.10
1.00
10.00
100.00
hours till deadline when started
Score drops if assignment started in last hour
Feedback
 Full
solution
– step-by-step instructions on how to set up the solution
 Specific advice if student chose one of the wrong
answers
– e.g. “It looks like you made a mistake calculating the
flux through the square loop. Did you forget that the
B-field decreases with 1/distance from wire?”
Impact of Timeliness of Feedback
 Randomly
split students into two groups for 1 week
– Induction physics, Faraday’s law
– group A received immediate feedback on problem set
– group B received feedback after due date of problem set
 Any difference in learning the physics of this assignment ?
– scores on standard magnetism diagnostic
 post    pre 
“Gain” = fraction of possible improvement g 
100  pre 
All questions <pre> = (18.30.8)%
g=0.510.02,
n ~280 students,
<post> = (59.71.3)%
Average Gains vs Timing of Feedback
Gain measured for induction questions
0.6
Immediate
feedback
 post    pre 
g
100  pre 
Delayed
feedback
0.5
gain
0.4
0.3
F2000
F2001
0.2
0.1
0
No strong evidence that students who received immediate
feedback learned more than students with delayed feedback
Discussion Board
 More
than 1000 messages per semester
– Information queries
– Gripes ( recommend monitoring strangetalk.net )
– Assignment questions (one topic per assignment)
» Student-student replies, TA-student replies, ..
» Example of thread next page
Student A My problem is the one that involves 20g of water at
10 degrees C and 300g of Ice at -10 degrees C and trying to
find the total change in entropy of the system. I think I need to
find the amount of ice that melts and the final temperature.
Thanks for any help in advance.
Student B i didn't have this question but try q=mc delta t
and go from there. Hope that helps.
Student A The problem I am running into is that there are two
unknowns - what fraction of the ice melts and what fraction of
the water freezes, while I only have one equation (if I take all
the Qs and equate them to 0). how can I solve for the two
unknowns?
Student C Think of this question as how much water freezes
instead of how much ice melts.
Student A Thank you so much - it was foolish of me to think
that the water could freeze and the ice could melt at the
same time. Your suggestion was like a light bulb flashing!
Lecture Notes
pdf, ppt made available before lecture
– Active-learning conceptual questions not included
page views of lectures Fall 2003
num of views
1500
1000
490 students
500
Lecture #
Lecture attendance still high > 75%
41
37
33
29
25
21
17
13
9
5
0
1

Gradebook
Assignments, pre-labs etc.
 Bubble-sheet scores from test-services
 TAs hand-enter
– Lab-grades, project scores
 Tremendous value
– Students find our “accounting” errors =>fix them
– Track performance
 Downside
– Not possible to segment by TA
 Upside
– Uploading of letter grades to registrar :)

Next Steps: Skill Profile
 Each
question => skill weights for several categories
– N/A, low, med., high-skill needed to solve problem
 Categories
– use of multiple concepts, geometry, algebra ….
 Calculate a “skill level” for each student in each category
skill level 
 weight
 weight
correct
attempted Problems
Provide students their updated skill profile each week
Meta-cognitive: “what type of problems do I get wrong?”
Wish/concern list
 Rubric
data entry
– TAs use rubric for lab-grading but enter total score
– Better would be a “graphical” interface of rubric
» TA “click” on a rubric-grid for each student
 Fast data entry
» Splits the scores up into each category,
 Allows student to monitor improvement
 More page tracking
– how often non-content pages viewed? e.g. solutions
 Need “assignment availability/closing” bug fixed
Conclusions
Redesign of physics courses @ ISU
– active engagement during lectures
– group projects on realistic modeling
– use webCT to free TAs from grading
» better use of TA time
» Cost-savings
– on-line assignments
» immediate, specific feedback possible
 Lectures, discussion board, gradebook
– well used
 Contact me with any questions, cogilvie@iastate.edu

Backup
TA Survey
Frequency
Online => Saved TA time
6
5
4
3
2
1
0
disagree neutral
agree
strongly
agree
Frequency
Online => more time in recitation
on problem-solving development
2.5
2
1.5
1
0.5
0
disagree neutral
agree
strongly
agree
Usage (I)
E.g. weekly quantitative problem set, 4-5 questions
– Each question ~ ½ page of work
– Random sample of 100 students mid-way semester
time left when assignment started
assignments

25
20
15
10
5
0
1
2
6
12
24
48
72
hours till deadline
96 120
Usage (II)
Random sample of 100 students mid-way semester
Time assignment submitted
40
Sunmitted

30
20
10
0
11 10
9
8
7
6
5
4
3
Hours left till deadline
2
1
0