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Final report Merrick Instructional Enhancement Grant 1998-1999:

Interactive homework web site for General Physics.

Wilhelmus J. Geerts

Department of Physics, Southwest Texas State University, San Marcos, TX78666.




1. Web-technology and boundary conditions

2. Electronic Homework questions

3. Application/Questionnaire/Teacher's view

4. Acknowledgements

5. References

Appendix A: Results questionaire

Appendix B: Proposal-text

Appendix C: CD with complete electronic homework site

Templates available on request: contact Gerald Farr at the Faculty Advancement Center.


1. Web-technology and boundary conditions.

Most of the computers at the physics department are hooked up to the local area network of the University and have thus access to the world wide web (WWW) and SWT's e-mail facilities. An IBM compatible computer running NT-windows maintained by students under auspices of Dr. Heather Galloway, acts as the server. At the start of the project there was no experience or expertise at our Department with using the WWW for intensive homework-assignments. Furthermore the bandwidth of SWT's window to the WWW was rather narrow, which made surfing the web in day-time impractical. As several apparatus maintained by different groups are involved in web-browsing, i.e. computer, network, and server, I initially chose for an approach which would let me easily identify problems and which would limit my role as technology-help-desk. The Fig. 1 below gives a schematic diagram of the PHYS1410-fall-98 electronic homework system. The questions can be retrieved from the physics-server similar to the normal home-pages. The answers are submitted by e-mail to a special SWT-account. Twice a week a special program opens up the account, checks all messages, and tabulates the scores. Although this setup limits the responsibility of the server to question-distributor, it has some major drawbacks:

  • Because the scores are submitted by e-mail, the system is rather susceptible to fraud. In particular with windows-97 which has browser and mail system integrated with the operating system.
  • The program that automatically opens all the e-mail messages, and performs the administration is quite a challenge and surely not a recommendable option for non-technically inclined teachers. I used C++ builder of Borland, which includes some standard POP3 procedures. Although I'm rather fluent in C, it took me a full week to code it.
  • A lot of students use computers on campus to submit their homework. The mail-part of the browsers on those computers needs to be initialized in order to be able to submit homework successful. This procedure has to be repeated every time the student logs in. Furthermore it is different for different browsers. It caused quite a bit of confusion among our students at the start of the fall-1998 semester.
  • As it can take quite a bit of time before e-mail messages are delivered it was not possible to give the students an instantaneous receipt acknowledgement. In particular in the beginning of the semester when a correct submission recipe was not known for all computer/browser/network combinations, this has caused confusion.

Because of these disadvantages the mailing method of Fig. 1 was replaced by the scheme of Fig. 2 from January 1999. Forms are directly submitted to the server of the physics department. No initialization of the browser is required and the system is less susceptible for fraud. At the server's site the administration of the scores was taken care of by a simple CGI-program written in C++ which also provided an instantaneous receipt acknowledgement to the students' computer. The system has been operated almost flawlessly in the spring-1999 semester.

wpe1.jpg (14034 bytes)

Fig.1 & 2: first approach and final implementation.

In fall-1998 I had little knowledge of HTML and heard of the existence of Javascript and Java. I bought a book HTML for dummies and Javascript for dummies and studied the code of some neat pages I found on the web. Although these books helped me in the beginning they are not suitable for setting up and maintaining an electronic homework web site. You need some reference books with the exact syntax of HTML and Javascript. Reference [6] and [7] appeared to be very useful. Be careful, as even the newest versions of Netscape and Microsoft Internet Explorer still contain bugs and behave inconsistently in some situations. The physics electronic homework site allows you to use only Netscape 4.06 or higher or Microsoft Internet Explorer 4.0 or higher. If you try to log in with another browser or version the server will kick you out.

2. Electronic Homework questions.

The homework questions were obtained from Prentice Hall publishing company as part of a book deal. Prentice Hall supports some of its books by extensive web sites. The book Physics written by Douglas C. Giancoli was supported by a so-called companion web site. It contained the last developments on Web-testing in Physics, i.e. a section with multiple-choice questions [1], a section with open question [2], a section with numerical questions [3], and a section with simulations [4]. In addition the site contained pages with related-links and pages with background information on applications. Although physicists developed most of those web technologies, these techniques are very well applicable to other areas as far as history, business, or French poetry. As the original Prentice Hall web site was based on a Unix system, I had to rewrite the submission procedures in all web pages. Furthermore the help pages were rewritten and the Prentice Hall jacket was replaced by an SWT coat.

2.1 Multiple choice section:

Each MC-section contained 10-25 MC-questions. After the student had completed the MC-quiz, it could push a button to grade it. A page that showed the score, the student's answers, and the correct answers was displayed. The student could than decide weather or not to submit or try over. As all students got the same quiz and the answers are shown afterwards this section was not so useful for homework-assignments. In the summer of 1999 I rewrote this section so that all answers are shuffled randomly and the students will get a tailored feedback (i.e. what pages or examples to study to improve the score). For those teachers interested in setting up this kind of MC-web pages I can provide you with a user friendly template and a score-registration program that runs under windows. The template can be easily edited by for example Wordpad or Frontpage. The new MC-section will be tested in the fall of 1999.

2.2 Open questions section:

Gregor Novak and Andrew Gavrin of IUPUI originally developed this section [5]. It contained several open questions. So far I have not used this section in my classes because of the work involved in grading those assignments. The authors suggest to grade10-20 students yourself and to let the others grade by graduate students. Another alternative is to make use of text-interpreters. Although this technology is still in the diaper-stage, preliminary results have shown that error margins of automatic grading programs are comparable to human-graders. Advantages of using the WWW for open questions are:

  • readability of the answers
  • option to grade the work without really knowing the author of the work
  • option to ask the students to grade some of their colleagues work anonymously.

I intend to start using this technique in my smaller physics classes.

2.3 Numerical questions section:

These sections were developed by using the software of Carl Adler of East Carolina University. It consisted of 7-15 open questions which initial conditions were generated by a random generator. The numerical answers had to be filled out in sufficient decimals. After finishing the assignment an automatic grading button had to be pushed. The result page showed your score, your answers and the correct answers. It was only possible to submit one time. For each new submission the initial numerical conditions of the problems would change. The big disadvantage of this system was the time most students needed to complete all the problems. Most of our students have sufficient time to do the problems but not in one block. Working on the problems for 30 minutes today and 45 minutes tomorrow was however not an option as the initial conditions would change every time the student had to log in again. For this reason I modified these sections and coupled the initial numerical conditions to the social security number of the student. Each time they logged in they will get the same problems, but different from their colleagues. The new sections will not give you the right answers after grading. It will only tell you if your answer is correct. We kept the original sections with random initial conditions accessible for the student. Most of the students would start of to print out a copy of the original section and the answers, work on those for a couple of days (discuss with their colleagues), and than once they figured out how to work the problems go for the new sections and get the credit for their homework assignment. During the fall-1998 semester two sections of PHYS1410 submitted every week this particular section electronically: close to 1800 submissions.

2.4 Simulations section:

This section contained 5-10 multiple choice questions around small JAVA-simulations called Physlets: for example the interference of two point sources is best explained by a small movie which shows the waves in a ripple tank. Wolfgang Christian of Davidson College developed most of the physlets. Although the development of physlets in Java can be quite time consuming and is not recommended for teachers who are not technically inclined, the application of existing applets in webpages is a relative easy procedure. The educational merit of using dynamic simulations instead of text and pictures is evident. Just try yourself:

http:\\\wg06\teaching.html (choose Phys 1420, chapter 16, simulations). I have used this section for one semester in my PHYS1420 class on a voluntarily basis. It is a great teaching aid for teaching concepts and avoiding equations.

3. Application/Questionnaire/Teacher's view:

The developed web site was used in 3 sections of Phys1410 during the fall-1998 semester. In Galloway's class (section 1) is was partly optional and partly mandatory. In Geerts' class (section 3) it was mandatory. Jackson (section 2) offered it as an extra practice-option to his students. At the end of the semester an extra questionnaire was added to the standard evaluation. The results are summarized in appendix 1 and speak for themselves. The comments marked with an x were addressed in the revisions made to the electronic homework site in January-1999 and August-1999.

In addition I would like to add the following conclusions from the teacher's point of view:

  • A good network, a well maintained server, and computer labs with the necessary software are crucial for an electronic homework web site.
  • Electronic homework assignments are a powerful way to drive students. As all students get different questions they can no longer copy the answers. Of course in the labs you can still hear a student asking for the help of his colleagues, "What do you have for problem 9?". Instead of "23.8 meters", the answer sounds more like "you have to take the product of the velocity and the time", which I believe is close to real Physics-talk.
  • Not all our students are that computer-literate. Furthermore you do not want your students to waste too much time with learning how to work with computers and web-browsers. In order to save time by using electronic homework assignments, you need a system that works flawlessly from the first day, a very well defined recipe, and a strict deadline-policy.
  • The feedback to the students can be easily tailored.
  • The automatic instantaneous grading with useful comments is very rewarding towards the students and time efficient towards the teachers.
  • It would be wisely to add a view lines to the student handbook about academic dishonesty regarding to electronic homework assignments. At the end of the fall-1998 semester we had two cases of fraud. Both suspects were talented students who were technically inclined. As web-assignments are quite new for the University some of the students might think it is just a game: a clear warning in the student handbook might avoid these situations. In January the electronic homework web site was redesigned so that it became less susceptible for fraud.

4 Acknowledgements:

We can only look farther because we stood on the shoulders of our colleagues or our predecessors. The work of the following Companies, Institutes, and Individuals largely contributed to this web site:

  • Companion Web site: Media Technology Group, Simon & Schuster Higher Education Division, One Lake Street, Upper Saddle River NJ 07458:

  • Mcat sections: Bosworth et al, ARCO MCAT SuperCourse (MacMillan, 1997). Copyright 1997, 1996, 1994, and 1991 by Stefan Bosworth, Ronald Drucker, Edgar Schnebel, Denise Garlan, Rosie Soy and Marion Brisk. Used by permission of MacMillan, Inc.:
  • Mcat-sections: The Virtual Prof's Physics Study Guide for the MCAT. Copyright 1997 by Glen Terrell and RonJon Publishing, Inc. Used by permission of Glen Terrell. For more information, go to
  • Physlets sections: Wolfgang Christian, Davidson College. Physlet Problems (c)Prentice Hall, Inc; written by Aaron Titus (North Carolina State University) and Wolfgang Christian, Davidson College:

  • Essay & application sections: (c)1997 IUPUI, all rights reserved. Written by Gregor Novak and Andrew Gavrin, IUPUI. Used by permission. TestMaker used by permission of Carl Adler, East Carolina University:

  • CGI: software of Thomas Boutell of Boutell Inc.:

Furthermore the following people on location have to be thanked:

  • Prentice-Hall: Laura Curless, Phyllis Bregman, Scott Pearlman, Ray Henderson
  • The Merrick-organization (financial support)
  • Faculty Advancement Center SWT: Gerald Farr and Jeff Schneider (technical support).
  • SWT Physics (in alphabetic order): Jim Crawford (applet literature), Heather Galloway (pilot run), Carlos Guttierez (encouragement), William Jackson (pilot run & proof reading the proposal), Victor Michalk (initiator), Don Olsen (proof-reading the proposal), Belinda Olsen and Pat Parks (grading).
  • SWT network and computer services: Mike Ferris, Heather Galloway, Jane Hughson
  • SWT library computer services: Phyllis Rowell, Todd Peters
  • The teaching assistants in the various computer labs on campus who have assisted our students to tackle the many startup problems.
  • Last but not least: the PHYS1410 students of Fall 1998 and the PHYS1420 students of Spring-1999 for their patience and valuable feedback.


5. References

[1] Bosworth et al, ARCO MCAT SuperCourse (MacMillan, 1997). Copyright 1997, 1996, 1994, 1991 by Stefan Bosworth, Ronald Drucker, Edgar Schnebel, Denise Garlan, Rosie Soy and Marion Brisk. Used by permission of MacMillan, Inc.. This kind of pages can be generated by for example multiple choice test maker developed by Carl Adler of East Caroline University. For more information on this check:

[2] Templates and directions how to author those open question tests are available from the web IUPUI web site by Gregor Novak and Andrew Gavrin, IUPUI.

[3] Those numerical question tests can be generated by TestMaker developed by Carl Adler of East Carolina University. For more information about the TestMaker program please go to:

[4] Most of the Physlets in this section are developed by Wolfgang Christian of Davidson College. This section was originally developed by Aaron Titus of North Carolina State University and Wolfgang Christian, Davidson College. More information on applets can be found at:

[5] "Just in time Teaching: blending active learning with Web Technology", Gregor M. Novak, Evelyn T. Patterson, Andrew D. Gavrin, Wolfgang Christian, Prentice Hall, Upper Saddle River, NJ, 1999, ISBN 0-13-085034-9.

[6] "HTML 4.0, no experience required", E. Stephen Mack and Janan Platt, Sybex publishing company, 1997, ISBN 0-7821-2143-8.

[7] "Javascript the definitive guide", David Flanagan, O'Reilly, 1998, ISBN: 1-56592-392-8.