UniServe Science News Volume 14 November 1999


Using the Discus Discussion Forum System in Problem-based Learning in Science

Mark Selby
Faculty of Science, Queensland University of Technology
Darren Pearce
School of Physical Sciences, Queensland University of Technology


As part of an internal teaching and learning grant the Faculty of Science at Queensland University of Technology has been implementing a problem-based approach to teaching in order to increase student interest and active participation in first year science1 and to foster development of vocationally-oriented generic skills. An obvious advantage of problem-based learning is that it emphasises problem-solving skills. However, intertwined with these problem-solving skills students are required to exercise a range of other generic skills in areas such as: information retrieval; development of critical and analytical faculties; scientific communication; and the ability to work well in a team environment.

The learning strategy adopted is based around the introduction problem-based learning modules that sit between more traditional lectures. Typically there would be two problem-based modules introduced in a given first year teaching unit; the first being, say, 3 to 5 weeks into the semester and the second being in, say, weeks 9 to 11 (assuming a 13 or 14 week teaching semester). Because we are dealing with first year units, the teacher would largely model the problem-based learning approach in the first module, with little independent work on the part of the students. The second module would be guided by the teacher but would require greater independence on the part of the students. In subsequent units, problem-based modules were developed that required progressively more student-centred learning and independence. Problem-based learning modules with these characteristics were developed for 5 foundation science units at QUT in Physical Science, Life Science, Environmental Science, Mathematical Science and Statistics and Data Analysis. Further problem-based modules were also developed for several units that follow from these foundation units. In this article we focus on a particular unit, namely Physical Science, and explain our approach to implementing the problem-based learning modules and the use of the Discus software system.


An important characteristic of the problem-based modules was that they needed to be offered in a flexible way so that students could access materials and communicate with other students or the teaching staff at their own time and place of choosing. Further important characteristics were the need to have a communication medium that fostered group interaction and collaborative learning and a means of assisting staff to monitor student progress and post guidance to students in response to their needs, in a timely fashion. A web-based discussion forum system (perhaps augmented with email) was chosen as the best way of achieving these goals. After investigating a number of on-line discussion forum systems we selected the freeware Discus system2 because it is designed and used by science teachers for holding scientific discussions and has the capability of handling chemical and mathematical symbols and equations. We have also made use of the relatively inexpensive commercial progeny of Discus, Discus Pro3. A recent article on using Discus in teaching chemistry has been published by its creators Paulisse and Polik.4

Using Discus

Discus uses a very different structure from that used by most other web-based discussion forums and contains many advanced utilities that are not normally found in discussion forum software. The main page in Discus, illustrated by the screen image shown in Figure 1, is divided into two frames: a list of menu options on the left-hand-side; and a list of topics on the right-hand-side. (It is also possible to set up Discus in a no-frames mode.) We will first describe how discussion topics are set up in Discus then we will describe the use of the menu options, including the administration functions.

Figure 1.

Figure 1. Screen image showing the main page for Discus. Menu options appear in the left-hand frame and discussion topics in the right-hand frame.

Discus uses a hierarchical structure rather than the threaded structure more commonly found with on-line discussion forums and newsgroups. In Discus the teacher determines the topic structure, which shapes the ensuing discussions in accordance with their teaching objectives. We have found the structured format of Discus to be advantageous in first year teaching because it is easy for beginning students to follow and the structure prevents students from becoming side-tracked by irrelevant issues. In Discus the teacher can set up topics that contain an 'Add new conversation' button, which gives students the ability to create new subtopics (threads) of their own. However, for later year units dedicated threaded discussion software may well be preferable to Discus.

The top-level structure in the Discus forum can be set up for a particular unit as is illustrated in Figure 1 for the unit Physical Science or it can be set up for a group of teaching units in the same discipline area as is illustrated by the Hope College ChemBoard5 which contains topics spanning multiple units: physical chemistry; analytical chemistry; general chemistry; and so on. At QUT most teaching staff preferred to have a separate forum for each teaching unit, this is feasible because it is quite easy to have multiple installations of Discus running at the same time but it should be noted that the freeware license for Discus limits any organization to no more than 20 separate forums2.

In administration of the Discus forum, it is the forum convenor who sets up the top-level structure and who assigns each of the top-level topics to one or more moderators. Each moderator has complete control of their topic area using the administration utility functions. Discus gives the teacher a great deal of flexibility over the way that the discussion forum is organised. There are 6 different items that can appear on a Discus page giving a total of 32 different types of possible pages (though not all of these combinations are necessarily sensible). Figure 2A shows a typical Discus page containing a list of subtopics; there is no limit in Discus to the depth to which subtopics can be nested. Subtopics are normally linked to message pages as is illustrated in Figure 2B. Messages in Discus are arranged in a conversational style in sequential order of posting with the most recent at the bottom (but the order can be changed). Subtopics can also be linked to web pages located at another site. This mechanism can be used to add content pages to Discus, for instance, to provoke discussion from students concerning a paper or web site or to link together lecture notes or supplementary material at one easy-to-find point of reference.

Figure 2a.
Panel A
Figure 2b.
Panel B

Figure 2. Panel A shows a list of subtopics and Panel B shows the conversational style of messages in Discus

One of the most important features determining our selection of Discus was the formatting option for mathematical and chemical equations and symbols. Discus uses its own formatting commands which are preceded by the use of a backslash "\" and take the form: "\code{text to be formatted}". Table 1 illustrates some examples of formatting in Discus. Alternatively, Discus will also accept simple HTML tags. However, the in-built formatting commands are more powerful and can be used for inserting special symbols, tables, adding hyperlinks or mailto links and for chemical and mathematical equations. A particularly useful feature of Discus is the way it works with Microsoft Excel; select the range of cells you wish to copy in Excel and then write "\table{}" in Discus. Between the braces "{}" paste the cells from Excel and they will appear in Discus as a formatted table. This feature is handy for providing a table of student results from quizzes or assignments. Further useful formatting features in Discus are the ability to upload image files and, in Discus Pro, the ability to upload binary attachments.

Item How it Appears in Discus Discus Codes
Mathematical Equation Table graphic 1. \b{p}\-{\i{f}} - \b{p}\-
{\i{i}} = \ch{DEL}\b{p}
= \int{\i{t\-{i}},\i{t\-
{f}}} \b{F} \i{dt}
Chemical Equation Table graphic 2. 2LiOH\-{(s)} + CO\-
{2(g)} \ch{->} Li\-
{2}CO\-{3(s)} + H\-
Hyperlink Table graphic 3. \topurl{http://science
Table Table graphic 4. \table{\b{Student Id}
\b{Quiz Mark}
2516993 5
2517761 8
2319462 7}

Table 1. Some examples of using formatting commands in Discus

The left-hand frame in Figure 1 contains menu functions grouped into 3 areas: (i) controlling the way that discussion items are displayed; (ii) documentation; and (iii) utility functions. In the area of utilities, Discus contains some sophisticated search functions for quickly finding messages when the forum grows to a large size. The 'New Messages' item can be used to find all messages posted since last time you checked the forum. The 'Edit Profile' item can be used to change your password or other information that the system stores about you. In Discus Pro you can store your photograph and other personal details. In both versions of Discus you can also elect to be automatically notified by email whenever a new message appears in the forum under a selected topic.

The convenor and moderators of the forum have access to the 'Administration' item via a password (failed attempts to enter this area are logged so that possible malicious use by students can be traced). The administration area provides an extensive range of functions for setting up the forum, adding new topics and subtopics, for moving, editing and deleting messages. Discus Pro offers an even more extensive range of functions for archiving, making backups and for automatic pruning of old messages. The editing and archival functions provided in both versions of Discus mean that it is possible for teachers to add content directly to Discus in a way which is similar to a more comprehensive on-line teaching solution such as WebCT.

Other important functions that the convenor and moderators need to perform in the administration area are setting up user lists and access control. In Discus discussion topics can be public or private. In a public topic anyone can post discussion; in a private topic area only moderators and students named on a user list can post discussion (but the forum can be read by anyone). We preferred to use private posting in most cases so that students were required to enter a username and password - in this case any flaming or other inappropriate posting can be traced. We did offer students the option of anonymous posting (in which case postings are still logged internally but user details are not disclosed on the forum itself). In Discus user lists can easily be cut-and-pasted from Excel and Discus informs you of any duplicate or invalid usernames and conveniently allows you to make adjustments. In our usage we noted these adjustments to usernames under the 'System Announcements' topic. In future we intend to link student usernames and passwords directly to our university's central system.

Discus Pro offers further valuable enhancements - it is possible to have private reading topics as well as private posting topics. We used private reading for group assignment topics to minimise collusion between groups of students. Discus Pro can be configured to allow students to edit their own posts for up to 30 minutes afterwards and for student self-registration (rather than using user lists).


We have found that the use of Discus has harmonised well with our use of problem-based learning projects in Science at QUT. In particular Discus has offered greater flexibility in the delivery of problem-based learning modules. Discus was also a valuable tool for fostering group work and collaborative learning. In student surveys and focus groups they have pointed out that they consider face-to-face contact with other students to be essential in completing group assignments but they were also quick to point out that Discus was valuable to them and that they would not like to see its use discontinued.

In the Physical Science unit 73% of students either agreed or strongly agreed that the Discus on-line forum system was helpful to them in completing the two problem-based modules in that unit. More extensive analysis of the use of Discus in the Physical Science unit over two semesters is presented in Table 2. In this analysis we have chosen to use "page views" rather than server "hits" as is more commonly done. A page view is recorded each time an HTML page is requested but multiple hits can be recorded for the same HTML page, depending upon its graphical content.

In common with other users of discussion forum systems we find that in Physical Science that students referred to the PCB101 forum quite frequently (an average of 140 times per student in semester 1) but that they contribute to the forum by posting discussion much less frequently (an average of 3.1 posts per student for semester 1). In semester 1, 205 students (77% of the class) posted to the group assignment areas on the PCB101 discussion forum at least once and 126 students (47% of the class) posted to the group assignment areas on 5 or more occasions. Usage of the forum in semester 2 was lower per student for both page views and for posting. This appears to result from two causes: (i) the smaller class size means that students had greater face-to-face contact with other students and with staff; and (ii) Physical Science was run over 2 campuses in semester 2. Students at Carseldine Campus reported that they hardly used the discussion forum at all because they were in frequent contact with each other anyway. Also, the Carseldine program ran in a compressed block mode so that there was little incentive, or opportunity, for Carseldine and Garden's Point students to communicate with each other. From this analysis it is clear that discussion forum systems are more valuable for larger classes than smaller ones.

Semester 1: 266 students Semester 2: 55 students
(two campuses)
Total Page Views 37367 5347
Average Page Views per day 381 56
Average Page Views per student 140 97
Teacher/Tutor Posts 288 72
Student Posts 832 104
Average Posts per day 8.5 1.1
Average Posts per student 3.1 1.9

Table 2. Data obtained from using Discus in the unit PCB101 Physical Science over 2 semesters

In order to increase participation, student posting can be made compulsory or assessment can be based upon the quality and/or quantity of postings made. We have refrained from introducing such measures because we feel that students ought to want to use the discussion forum because they find that it is intrinsically valuable to them in learning. Not because it is forced upon them. In the Physical Science unit we have found that Discus forum fitted the modules in problem-based learning in groups that we introduced in 1999, in a most natural and useful way.


  1. Allen, D. E., Duch, B. J. and Groh, S. E. (1996) The Power of Problem-based Learning in Teaching Introductory Science Courses, in Wilkerson, L. and Gijselaers, W. H. Bringing Problem-based Learning to Higher Education: Theory and Practice. New Directions for Teaching and Learning, 68, 43-54, Jossey-Bass, San Francisco.
  2. http://www.discusware.com/discus/
  3. http://www.discusware.com/pro/
  4. Paulisse, K. W. and Polik, W. F. (1999) WWW Discussion Boards in Chemistry, Education Journal of Chemical Education, 76, 704.
  5. http://www.chem.hope.edu/chemboard/

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UniServe Science News Volume 14 November 1999

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