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By Chung Chieh
Department of Chemistry, University of Waterloo
Waterloo, Ontario, Canada N2L 3G1

05/28/99 to 06/03/99

Internet or web sites can store texts, articles, figures, computer simulations, multimedia segments, assignments, quiz and test questions, student records, discussion records and other materials. Information can be in the form of textbooks with the added flexibility of being hyper-linked for dynamic access. Because browsers are easily available, websites offer many benefits for educators and students. Websites have replaced posters, loudspeaker announcements, and notice boards.
I have developed a website for students at the University of Waterloo, and it has been in operation for a few years. Files for the website reside on a twin-CPU SUN Ultra Enterprises Unix server, but many pages have links to other internet sites. It can be accessed by anyone using a browser anywhere at any time, thus, it serves as a cyber office.

This website evolved from an earlier design of a Computer Assisted Chemistry Tutorial (CACT) system, which resided on a server of a local computer network of IBM PCs. Our students used CACT for several years before we adopted the internet technology. Thus, we call the web site Internet CACT, or simply CACT.

One of the important features for the Internet CACT is to conduct quizzes over the internet. Students have the choice of going to small group tutorials and write 5 class-room quizzes or writing 9 to 10 CACT quizzes over the Internet per term. During the Fall term (September-December, 1998), 650 of the 995 students registered in Freshman Chemistry I (CHEM120) have written 9 CACT quizzes each over the Internet site. During the Winter term (January-April), 390 of the 610 students registered in Freshman Chemistry II (CHEM123) have written 10 quizzes each over the Internet. Their marks were recorded on the same server. A locally developed program is used for this operation. While it is functioning, the website is constantly been maintained, developed, and updated.

A counter was placed in the CACT site during the Fall term of 1998. Usually, the numbers of access is about 20 per day. However, a few days before major tests and final examinations, the numbers of access were between 500 to 700 per day, usually at night. When the counter was in place, between 5 to 10 seconds was added to the time required for loading the menu. We have disabled the counter, for the convenience of students.

In this article I will share my experiences in implementation, design, development, operation, and maintenance, comment on the future outlook of using websites for teaching and learning, and will discuss our quiz design and operation. The CACT website address is


1. Introduction

Schools and universities stand at the forefont of science and technology. Students and teachers constantly look for new and exciting things to learn and do. Teaching without learning soon leads to boredom. The pleasure of learning multiplies if it is associated with teaching. Thus, the introduction of a new technology almost immediately affects professors, teachers, and students in the universities, colleges, and schools.

Technologies such as radio, audio recorders, television, video recorders, etc. have greatly affected the learning and teaching profession, especially on the generations slightly before us. Some of us can only relate to the introduction of computers, and its effect on teaching and learning. However, we have to recognize that applications of any of these technologies to teaching are called media teaching or media education. Computer and internet technologies affect teaching and learning more than other media before them in number of people involved.

When audio and video recorders were introduced, educators began to use them to store and deliver teaching materials. Some teachers feared that media teaching would replace them, but media teaching changed the nature of teachers' work. Furthermore, TV and Film in media and teaching has had a great impact on our society and on our life-time learning process.

When personal computers (PC) were introduced, many teachers rushed to employ them for storing and delivering teaching material. Again, some were afraid that computer aided instruction (CAI) would threaten the teachers' job security. Almost 20 years has passed since the PC came to the market place, and over the past 20 years, several generations of the PC have come and gone. A more recent event is the increase in the number of internet (web) sites. Abundant instructional aids are available from the Internet, for example, the website for media teachers in the UK (dead link removed).

An Internet Site for Freshman Chemistry has been developed and evolved for more than 15 years. At the start, this site was tested by a small group of students in the chemistry program on a local network of computers in one room. Then, it was placed on a campus-wide computer network for about 800 freshman chemistry students.

The popularity and the prospect of the Internet (for example see The Future of the Internet as an Educational Medium) compelled us to convert the CACT into internet documents. During 1997 and 1998, both the DOS and the Internet versions of CACT were available. In the Fall of 1998, only the Internet version of CACT was maintained and supported. We are constantly improving it, and problems are dealt with as soon as possible. The CONFCHEM audience accesses the same site as our Freshman Chemistry students at the University of Waterloo.

Students have written CACT quizzes over the Internet CACT site for the past two terms. The experience is interesting and valuable for future improvement.

2. The Beginning of CACT

Science educators often ask when and how things start and why? Thus, let me start from the very beginning.

The introduction of personal computers (PC) in the early 1980s had a great impact on the educational profession, as had radio, movie, TV, and other media that were introduced before the PCs. During the early 1980s, the University of Waterloo received a donation of PCs from IBM. The Physics and the Computing Services Departments teamed up and developed a local network to provide computing for physics students. Partly because of my interest in the project, 8 PCs were allocated to the Chemistry Department to set up the same type of local network for Chemistry students. This photograph shows that first local network of personal computers in one room.

The graphic capability of the PCs greatly tempted us to simulate chemical and physical phenomena. We wanted to show how systems respond to the driving force of change. For example, many of these programs were collected by the SERAPHIM project. However, information or instructions provided to students must be organized, and instructions are required to tell students how to use the simulations for learning and skill developing purposes.

The faculty members were very eager to become computer literate after the introduction of PCs. At a computer conference, I heard lectures on the hyperlink concept. That concept was later applied for the development of Hypercard. We were determined to make our students computer literate. Having the computers available in the Department, I designed a course to teach chemistry students to write software to solve chemical problems and handle chemical information. Some enthusiastic students, in particular Chris Reil and Adam Asworth, helped me in the development of a primitive browser for processing text files which had imbedded Script tags. We called these files Instructions. The browser is an important component of the early Computer Aided Chemistry Tutorial (CACT) system.

During those old days, we had a great pleasure in trying different things on the computer. The students and I have learned a great deal from each other. Both Chris and Adam have gone on to computer related careers since their graduations from the Chemistry Program.

3. Computer Aided Chemistry Tutorials

Computer Assisted Chemistry Tutorials (CACT) were instructions managed by a browser-like program called Resource written in the Quick Basic language. The CACT files resided in a server of local area network (LAN) of personal computers. Students accessed the CACT system from any workstations of the LAN in a disk operating system (DOS). The DOS CACT system was in operation between 1980s and 1998, but we began to convert the files into Internet documents in 1996, and placed them on the Internet in 1997. Students accessed either version in 1997-1978, but only the Internet CACT was maintained and supported by the Fall of 1998.

Both the DOS and Internet versions follow the same design, and the design of the DOS CACT is described in this section.


<= Esc

An acid is a substance
that dissociate into ...
when dissolved in water ...

Resource starts by displaying a Menu, which is equivalent to the table of contents in a textbook. Each item on the Menu is linked to an Instruction file. A user moves the hilighted choice (base) from the Menu by using appropriate keys that are usually used to control the cursor movement. A user can move one item or 20 items at a time in either direction by typing an appropriate key. Typing any key will move the choice one item at a time in the forward direction. By pressing the Enter key, the Instruction file linked to the highlighted (base) item of the Menu will be displayed. When a user depresses the Esc key, the Menu is displayed for the user to make another choice. At that time, we had to show students where the Enter, Esc, PageUp, PageDown and the arrow keyswere on the keyboard, because most of them had not used a PC before.


At the start, the DOS CACT was a flexible system. Users had to keep track of the documents they have read and know what they need to study. In later years, the CACT automatically recorded a history for each student to help the user to keep track of his or her study. My own CACT history was the first item on the Menu, and the History showed the date and the title if and only if he or she had answered the Dialogue questions. This file resided in the users private account called CACTHIST, and the contents were updated each time.


A CACT Subject
What is an acid?
What is HCl?
Why is HCl an acid?

An acid is a substance
that dissociate into ...
when dissolved in water ...
Demonstration         Quiz
Which is produced by 
an acid?
H3O+     H2O
OH-       .OH

Every subject on the Menu of the CACT system has four potential components: Instruction, Dialogue, Demonstration, and Quiz. Unfortunately, the DOS based technology enables only one of these to be displayed at a time. By typing appropriate keys, the user can go from one component to another. All subjects have the Instruction and the Dialogue, but some have all four components.


The Instruction and Dialogue are handled by Resource, which is linked to Demonstrations via the Menu. Quiz is handled by a separate program to conduct tests and record marks. They all work together as a single system.

The strategy for CACT may be applied to any subject or course. A considerable effort was required for preparing the content and we had a full implementation only for the the large first year chemistry courses.

When a resonable amount of content were implemented, we asked about 120 Chemistry-Major students to try the preliminary version. Then we released it to about 800 students who are taking the freshman chemistry courses. These students are from various programs in the Faculties of Mathematics, Health Studies, and Sciences. The engineers at the University of Waterloo offer their own version of a one-term freshman chemistry course, dealing with equilibrium and stoichiometry.

The CACT worked well with the local area network (LAN) called JANet, and University wide network systems called WatStar (DOS and Window 3.1 operating system), and later Polaris (Windows 95 being the default operating system).

Starting in 1997, students entering university did knew what DOS represented. To them, the Windows system is how computers should work. Changes to CACT were unavoidable and some possible changes were to:

  • write a management system based on the Window system for CACT. Languages C++, Visual Basic and Java have been considered, and their potentials explored.
  • write a CACT management system using a language for the UNIX operating system.
  • adopt one of many course development packages or teaching systems as they call them for the CACT.
  • take advantage of available browser technology.

The advantages and disadvantages of each of these possibilities have been carefully considered in view of our strength and resources.

Since web browsers have been distributed free of charge, and they have been readily available at the university work stations (computers), we decided to make the CACT available on the Internet. Theconversion was underway in 1997. We tested it extensively with browsers abailable on the University computing facilities.

4. The Dialogue and Confidence Building Questions

The name Computer Assisted Chemistry Tutorial (CACT) implies the original intention of learning by working. After having studied a chemical theory or concept, the student apply it to solve problems. By then, students have acquired some skills, not just memorized some statements. The CACT is based on this pedagogical practice, and self testing is an important part. This part was called the Dialogue in the DOS CACT, because students engaged in conversations with computers. Since the interactivity between computers and users over the Internet requires more time to implement, questions in the Dialoguebecome Confidence Building Questions in the Internet CACT.

4.1 The Dialogue

In the early DOS CACT, the self testing was done in the form of a Dialogue between a student and a computer. A Dialogue consisted of a series of questions, and the computer gave the user one at a time. Since programming a computer to process students' input is a difficult task, we used questions that require short answers. A complicated task is broken down to many questions, and students were asked to provide key answers in steps.

For each question, answer-response pairs were prepared. The computer gave a corresponding response to the student's answer. The responses pointed out some common mistakes used in deriving theseanswers. A mark was given to indicate the quality of the answers, but it was not recorded.

A student could answer a question as many times as he or she wanted. The purpose of the Dialogue is to build students confidence and to acquire skills by solving problems. Setting up answer-responsepairs in the Dialogue was a very demanding task.

Some concepts or theories can be taught by asking a series of related questions. Some modules were made up this way.

We can also give a number of problems fo a subject, each requires a different application of the same concept or theory.

In the early 1990s, students came to the computer room for the CACT. Watching them working on the problems was a rewarding experience, and students also directly interacted with me. After the network has expanded to campus wide with many computer rooms, and especially after having converted to the Internet CACT, I miss the opportunity for direct human interactions.

Over the years, some students have use CACT extensively, and a few have even point out the errors and made suggestions to improve CACT. Jason Ekert a former student in the course, proof read the files after he completed these courses. Of course, I appreciate having the feedback very much, and some of them realize it.

4.2 Confidence Building Questions

Questions in the Dialogue of the DOS version of CACT have become Confidence Building Questions of the Internet CACT site. Common browsers do not provide interactive responses to correspondinganswers in the form of Dialogue. Java applet or other programs have to be implemented. We have not had the time to develop a Dialogue approach to the Internet version of CACT yet.

In the current version, we put all the questions together, and provide hints, suggestions or considerations as well as hidden answers. Over the past two years, we have tried various techniques in theConfidence Building Questions. On some pages, we specify the skills students acquired in solving these problems.

Rather than learning the chemistry directly from the computer screen, Many students print the web pages in the Internet CACT for their study.

Having the appropriate number of quality questions in a subject is important. We are constantly improving the Confidence Building Questions of the Internet CACT. Time and effort are required to read the pages and make changes. Thus, building a web site is a real labour of love.

5. Demonstrations

One of the early intentions of Computer Assisted Chemistry Tutorials (CACT) was to provide computer Demonstrations, which could be simulations of chemical principles, visulization of chemical concepts, demonstrations of experiments, and illustrations of theories.

For simplicity, demonstrations were called Demos in the DOS version of CACT. We implemented selected topics, each had a Demo as an enhancement of our teaching. We did not intend to cover all the lecture material or course content.

5.1 Demos

Demonstrations of term I
Battery Galvanic cell simulation
BondEL Chemical bond length and energy
Conventn Conventions used in CACT
EMWave Electromagnetic radiation wave
Gaslaws Gaslaws
HBond Electron density of H-H bonds
Hybrid Hybrid atomic orbitals
KinetGas Gas kinetics
Limitn Limiting and excess reagents
Molecule User controlled molecular display
Orbital Electron density of atomic orbital
PeriodTb Electronic periodic tabel
PiBond Electronic density of pi-bonding
QuantNum Quantum numbers
Spectrum Simulation of spectrum
TVP The ideal gas law
VSEPR VSEPR and molecular shapes

The personal computers' ability to display vivid graphics in color has attracted many educators to write programs to demonstrate (Demos for short) chemical concepts and theories. We have also written a number such programs, which were organized for students to use in the DOS version of CACT, first for students in the Chemistry programs, and then for all freshman chemistry students.

The Demos used for the first term are listed in the Table here. Most Demos were written by me, in the Quick Basic language. The Demos were organized using the Menu like that shown on the right. Each Demo had its own Instruction and Dialogue. Few Demos were adopted from other sources, because of copyright and difficulties in their integration into CACT. Approximately the same number of Demos were written for the second term freshman chemistry, but for brevity, they are not given here.

The drawback of the DOS version of CACT was that the Demo and its Instruction could not appear on the same screen. This created some inconvenience for students, because they had to copy down the points in order to fully realize the benefit of the Demo. Having the Instruction and its Demo on the same screen would have been more convenient.

5.2 Loss of Demos in the Internet CACT

Because the Demos are written in Quiz Basic, they cannot be directly implemented in the Internet documents. If they were hyper-linked on the pages and the user clicks them, the users' computers will ask if they want to download them onto their computers. Such an arrangement is not practical for freshmen taking chemistry, and the Demos were not included in the Internet CACT. Thus, the Demos ceased to function in the Internet CACT, due to the change in technology. However, the Demos can still be used during lectures in classrooms with computer display facilities.

It is possible to rewrite the Demos in Java applets or Java scripts. However, due to time constraints, these have yet to be done.

5.3 Advantages of Internet CACT

Despite the loss of the Demosmaking CACT available on the Internet offers many advantages over the DOS CACT:

  • Special chemical terms can be hyperlinked
    to related documents for further help.
  • Diagrams, illustrations, and animated demonstrations (such as the ozone hole animation here) can be imbedded in the documents to make them more interesting.
  • Audio files, video clips, Java Applets, and other presentations can be hyperlinked or imbedded to make the documents multimedia. Implementation of these features will, no doubt, be easier in future generation of browsers.
  • The current html-type documents can easily be made to offer pleasant and attractive presentations.
  • The browsers capability to search key words can be applied for enquiry type of approach for students.

Because computers are close to each other in our computer labs, we have not included any sound tracks, nor have we included any video demonstrations. These require much more effort to implement.

Key word searching is very useful for active learners, but most students are passive learners.

6. CACT Quizzes

Quizzes administered at regular intervals demand that students study according to a schedule that we have set for them. Thus, we traditionally have small group tutorials and quizzes. When the DOS CACT was in use, it offered students an opportunity to write quizzes administered by computers in a DOS environment. After CACT was made accessible on the Internet, students had the opportunity to write quizzes over the Internet.

In this section, I will review the traditional Small Group Tutorials and Quizzes, the DOS CACT Quizzes, and the Internet CACT quizzes. I will share my Experience with CACT Quizzes to the extend of addressing issues in computerized quizzes in general. Furthermore, I will give reasons for our Strategies for Quizzes.

6.1 Small Group Tutorial Quizzes

Freshman chemistry classes have increased over the years, and now the classes have approximately 200 students per lecture section. There are several lecture sections in the Science Faculty, totalling more than 1000 freshman chemistry students in the Fall term, and more than 700 in the Winter term. The Department used to give biweekly small-group tutorials to about 30 students, and that class size would have increased considerably had CACT quizzes not been available. At the end of each small-group tutorial, we administer a 15-minute written quiz. Students solve one problem per quiz. The quiz papers are collected and marked by tutors, and they are returned two weeks later. These tutorials are offered so that students can ask questions in a less formal atmosphere. Most students, however, attend them biweekly to write quizzes.

Writting quizzes has always been a part of our Freshman Chemistry courses, the DOS CACT and the Internet CACT administered quizzes are substitutes for written quizzes in the tutorials.

For the past many years, students have written five (5) quizzes by attending 5 small group tutorials or nine to ten computerized quizzes. During 1998-1999, more than 70% of the students opted to write the quizzes over the Internet.

6.2 DOS CACT Quizzes

During the 1980s, our local area network (LAN) of computers was only lightly used. Following several years of running the DOS CACT on the LAN, I implemented the computerized quizzes, which followed the Dialogue format. In the Dialogue, students could answer a question many times, and the marks were not recorded. In quizzes, marks were recorded.

Each CACT Quiz consists of 5 to 10 questions randomly chosen from a pool of questions. Marks were the same for all questions. Partial marks were awarded. Three question types have been used:

  • multiple choice questions - The student enters a letter to indicate his or her choice,
  • questions requiring short-answers - The student enters a keyword, symbol, or term,
  • questions requiring numerical answers - The student must enter a numerical value.

The computer displays one question at a time, and there is no time limit within which to give an answer. As soon as an answer is entered, the computer reveals the mark earned for the question. For a correct answer, the computer returns with a thought provoking comment or question. For an incorrect answer, a hint is given.

Many years ago during a lecture, a student made a suggestion:

"Sir, we know the purpose of CACT Quizzes is to encourage us to learn, why don't you give us a second opportunity to give a correct answer for partial marks after we have seen the Hint?"

The class applauded and the strategy of quizzes was changed thereafter, partly also because I wanted students to read the Hints carefully. The Hints suggested a formula to use or a theory to apply, but the answers were not given. A student could answer a question n times, but the earned mark would be divided by n. We have not carried out research to see if such a strategy indeed led to more learning, but the number of requests to raise their quiz marks was drastically reduced.

At the end of a quiz, the mark earned for the quiz was displayed together with previous quiz marks for the students to review.

6.3 Internet CACT Quizzes

The conversion of the Instruction and Dialogue in the DOS CACT into Internet documents was completed early 1998. At this point, I wanted to begin quizzes over the Internet in the Fall term of 1998. Planning, exploring possible software, modifying, testing, and making up the Internet CACT Quizzes was my project for 1998.

After having explored several possibilities, I decided to modify a locally developed program called for the Internet CACT Quizzes.

During the winter term of 1995, Nevil Bromley and Paul Snyder of the Faculty Projects Group at the University of Waterloo developed a preliminary version of the program During 1997, there had been some limited testing and applications of the program, with very limited support provided by the Information Systems and Technology (IST).

Together with Wai Chun Li, a former Chemistry graduate working on his Computer Science degree at that time, we got a copy of, and tested it. The question formats used for are similar to those of the DOS CACT Quizzes, but now students can point and click their choices when is used to ademinister the quizzes. Questions requiring keywords and numerical values as answers are handled the same way as the DOS CACT Quizzes.

The program sends quiz marks to a quiz master in the form of an e-mail, and the quiz master has to extract the marks from these e-mails. Thus, students can write the quizzes any number of times. On the other hand, the DOS CACT Quizzes checked the student mark every time he or she started a quiz, and the mark earned during (not after) the quiz is immediately recorded. A student has only one chance to write a quiz. Once they start the quizzes, they have to finish them, because if they stop or turn the computer off, the marks they have earned at that time become their marks for those quizzes.

I decided to modify so that I could incorporate the strategies and designs used for DOS CACT Quizzes, which have worked well. We have consulted many Perl experts about file handling students quiz marks. We eventually used a technique used in the DOS CACT Quizzes.

We have added an interesting and useful feature to the selection of questions from a pool of questions in our modified We divided the pool of questions into groups, and a definite number of questions can be chosen from each group to make up a quiz. This feature enables the questions to be grouped according to difficulty, topics, style, or type (multiple choice, numeric answers, key-word answers). Thus, several skills can and will be tested in a quiz.

Together, Wai Chun Li and I tested how the system behaved under various conditions. For example, we tested the program as if three students were writing a quiz at the same time. During the past year, we modified the program to accommodate the problems experienced by students.

During the Fall term (September-December, 1998), 650 of the 995 students registered in Freshman Chemistry I (CHEM120) wrote more than 7 quizzes each over the Internet CACT. During the Winter term (January-April), 350 of the 606 students registered in Freshman Chemistry II (CHEM123) have written 8 or more quizzes each. Seven and eight best quiz marks were used to derive an average for the two terms respectively.

April 5, 1999, was the last day of lectures for the Winter term. April 4 (Sunday) was set as the deadlines for two CACT Quizzes. As a result, more than 150 students tried to write their quizzes, and unfortunately, the Internet server went out of service. The system manager thought that heavy usage by students writing Internet CACT Quizzes that day might have contributed to the problem. In the future, deadlines shall be set during office hours on week days to avoid this problem recurring.

A special CACT Quiz has been set up for CONFCHEM participants, whose identity and marks are not checked or recorded.

6.4 Problems of Computerized Quizzes

Computerized quizzes can be given either under the supervision of a proctor in a computer room where the students write the quizzes or unsupervised, in which case, no proctor is present when a student writes a quiz. Students writing unsupervised quizzes over the the Internet can do so at any time from anywhere. Problems or issues for the two quiz types are different. Since the CACT Quizzes are unsupervised, the problems addressed here are for the unsupervised quizzes. These problems can be divided into computer related and people related categories:

6.4.1 Computer related problems

6.4.2 People related problems

6.5 Strategies for CACT Quizzes

Link to Conference: