The Evolution of Web-Based
Activities in Physics at Illinois
Tim Stelzer and
Five years ago, the Department
of Physics at the University of Illinois undertook a complete revision
of the introductory courses. The details of this revision have been
reported in the paper "Parallel
parking an aircraft carrier" in the FEd newsletter, Summer
1997. A key component of the course revisions was the implementation
of web-based homework and an on-line grade book system. In this article,
we will describe the evolution of this system to include delayed
feedback homework, "Interactive Examples" with sophisticated
help sequences, and preflights for "Just-In-Time Teaching."
The Department of Physics has
been using computer-based homework for more than 25 years1.
As part of our course revisions, we exported our Novanet-based exercises
and grade book to the web. This move dramatically increased accessibility
of our material for both students and faculty, and it has been very
The original homework problems,
which are still being used, typically consist of a physical situation
about which the students answer several quantitative questions. A
help button is also available which reveals hints to the problem?
solution if requested. For example one problem reads: Two electrons
and two protons located at the corners of a square as shown in the
figure. Calculate the x and y components of the electric field at
the center of the square, and the x and y components of the force
on the left proton due to the other three charges.
The student can enter their
answers in a textbox and hit the submit key. The computer immediately
indicates which responses are correct and which are wrong. The student
can then rework the incorrect responses and resubmit them, repeating
the process as many times as necessary until all the answers are
Our experience with this type
of homework is similar to that chronicled at North Carolina State2.
Students enjoy the flexibility of doing the homework from any web
browser. They also appreciate the immediate feedback and typically
continue with a problem until they have everything correct. Indeed,
student scores on the web-based homework are very impressive. Often
students come to office hours and say "I know the x-component
of the electric field is supposed to be zero, but why?" This
illustrates one of the strengths of immediate feedback. Students
are provided with the opportunity to immediately identify their misunderstandings
while the problem is fresh in their minds which greatly increases
the incentive to confront their difficulties and clarify their understanding.
A disadvantage to immediate
feedback is that it eliminates the incentive for students to check
their own work. Students find it is much more efficient to attempt
a problem and let the computer tell them if they're right. Indeed,
a common mode of operation is for students to enter "0" for
all of the questions and submit their answer. Since frequently several
components of a vector are indeed zero, the computer will immediately
identify these as correct, eliminating the need for students to think
about these questions. They then focus their efforts on the "real" problems.
To reinstate the incentive for students to check their work, we added
one problem to each assignment that has delayed feedback. Students
are permitted to resubmit and change their answer to this question
as many times as desired up to the deadline. But, similar to hand-graded
homework, they don't receive any feedback about the correctness of
their answer until after the deadline for making changes has passed.
These new delayed-feedback problems seem to have had the desired
effect of forcing students to thoughtfully and carefully check their
work, and we have observed a strong correlation between students'
performance on these questions and their performance on exams.
Another common experience we
noticed with students' interaction with web-based homework is that
of students often asking for the help to be displayed before they
even read the problem! As a result, the "helps" were being
viewed as part of the problem statement. Indeed, we believe an important
shortcoming of most computer homework is that the help and feedback
mechanisms are typically a monologue, despite the educational research
findings that a dialogue is more effective. To help address this
shortcoming, we have developed web-based exercises called Interactive
Examples (IEs) that are designed to actively engage the students
in a Socratic dialogue and promote concept-based problem solving.
In each of these IEs, students are asked a single, somewhat challenging
quantitative question. If the student can successfully answer this
question, credit is given for the exercise and some optional "follow-up" conceptual
questions are asked to test this understanding. If the student cannot
successfully answer the initial question, a help dialogue, which
takes the form of a series of additional questions, some conceptual
and some quantitative, guides the student to develop a problem-solving
strategy to answer the initial quantitative question. Eventually,
as the student makes use of the help given in the computer responses,
he or she is able to arrive at a correct solution to the initial
question. The amount of help needed varies with the student. The
software is also designed to allow the student to interrupt the dialogue
and answer the initial question at any time, thereby reducing the
tediousness often associated with web-based homework questions. The
student can also continue to ask for help and be led to deeper and
deeper levels of interim questions. Once the student has successfully
answered the initial question, a recap of the strategy is presented,
and finally, optional follow-up questions are posed to allow the
new knowledge to be tested and applied. We have developed over 50
IEs for use in our introductory courses, and you may view them at http://www.physics.uiuc.edu/tycho/index.html.
Students have received these
new IEs enthusiastically. We have conducted informal interviews and
anonymous surveys, and an independent team from our Office of Instructional
Resources has conducted focus groups to assess student satisfaction.
The reports are all consistent. Students find IEs intuitive and important
to their understanding of physics. A typical comment from a student
is: "it actually helps you when you're stuck to not only get
the problem right, but helps out knowing how to do the same thing
again and feeling confident in the physics behind the problem. This
is a must. it would definitely help me do better in this class. it's
like having a personal TA to assist you with every problem when you
Another nice feature of IEs
is that every submission a student makes while working through the
problem is logged. We have used this information to study how students
interact with the IEs, and our preliminary analysis is promising.
Most students ask for some help initially, but are able to solve
the problem without using all of the help available. As we continue
to study these logs, we will continue to refine the IEs and assess
All of our homework and grade
book utilities are written as Perl scripts in a package we call Tycho.
We continue to adapt these drivers based on our experiences as well
as advancements in physics education research. Most recently, we
modified Tycho to accommodate the introduction of preflights
for Just-In-Time Teaching3 into our courses.
Preflights consist of multiple-choice
and text box questions that students must answer prior to each lecture.
These preflights encourage students to preview the material before
lecture and also provide an opportunity for the lecturer to identify
student difficulties with the material. In order to assist the lecturer
in efficiently extracting information from the students' responses,
we have incorporated a sophisticated preflight module into our grade
book. In addition to providing statistics for each of the multiple-choice
questions, the module also offers powerful filtering options to quickly
identify common student difficulties. The faculty has been very pleased
with this functionality, and preflights are now being implemented
in several of our advanced, as well as introductory, courses.
Through our experiences of improving
the introductory courses at Illinois, we have learned several important
lessons. First, developing quality materials always requires a significant
investment of both time and money. It is imperative that we combine
our experiences and resources in this endeavor. Whenever possible,
we have borrowed material directly from, or based our work on ideas
from, the physics education community. In a similar spirit, we encourage
others to take advantage of our experiences and materials and assimilate
them into their courses. You may view all of our work at www.physics.uiuc.edu/tycho/index.cfm,
or contact us at firstname.lastname@example.org.
- D.J. Kane and B. Sherwood, "A
Computer Based Course in Classical Mechanics" Comp. and
Educ. 4, 15-36 (1980); L.M. Jones, D.J. Kane,
B.A. Sherwood and R.A. Avner, "A final exam comparison using
computer based instruction," Am. J. Phys. 51,
533-538 (1983); L.M. Jones and D.J. Kane, "Network use in
central management of large university physics courses," J.
Comput.-Based Instr. 19, 77-81 (1992); L.M.
Jones and D.J. Kane, "Student evaluation of computer-based
instruction in a large university mechanics course," Am.
J. Phys. 62, 832-836 (1994).
- Scott Bonham, Robert Beichner
and Dueane Deardorf "Online Homework: Does It Make A Difference?" Physics
Teacher 39, 293-296 (2001).
- Gregor M. Novak, Evelyn T.
Patterson, Andrew D. Gavrin, and Wolfgang Christian, Just-in-Time
Teaching: Blending Active Learning with Web Technology (Prentice
Hall, Upper Saddle River, NJ, 1999).
Tim Stelzer and Gary Gladding
are in the Department of Physics at the University of Illinois
(Urbana-Champaign). Tim is a researcher in the physics education
group, and is currently working on the development and evaluation
of interactive examples. Gary is an experimental high-energy physicist
who has devoted a significant fraction of his time to physics education
in the last five years, and led the introductory course revision
effort at Illinois.