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Using Multimedia to Change the Way We Teach

Jon M Pearce
School of Physics and Faculty of Science Multimedia Teaching Unit,
The University of Melbourne

1 Introduction

Lecture theatres in many universities are commonly being set up with multimedia facilities: on-line computers, colour video projection, audio-visual facilities. How can these facilities be effectively used to enhance lectures and engage students more deeply in their learning? This paper addresses the issue of how one can use multimedia in lectures and what is required in preparation. The illustrations come from a second year electronics course for physics students.

2 A Development Project

A project within the School of Physics at The University of Melbourne aims to develop computer-based materials to improve lecture presentations in physics. The project aims to utilise recently renovated lecture theatres to convey visually some of the more abstract and challenging concepts in physics courses. The materials being developed are currently being used with students in a second year electronics subject presented in a theatre that allows you to use blackboards, overhead projections and computer screens simultaneously.

The role of these developed materials has been twofold:

* to replace "hand waving" descriptions of how mathematical graphs behave, with controllable animations;

* to present simple simulations of circuits that focus on a particular aspect of the circuits' behaviour for which students generally have trouble developing an intuitive understanding.

In addition, since the computer is present during every lecture, and does not interfere with overhead projections or blackboards, many scanned colour images can be presented to enhance the lecture's content. Not a great educational innovation, maybe, but it adds a little more interest to a lecture when a picture can be presented as an aside without interrupting the flow of the lecture.

3 Two Types of Presentation

This paper presents two types of presentations that have been used with students: mathematical presentations in which graphs are animated in a controlled fashion to illustrate a variable changing, and simple simulations in which particular aspects of a circuit can be highlighted. A combination of Mathematica (1), QuickTime (2), SuperCard (3) and HyperCard (4) are being used for these presentations.

3.1 Using Mathematica to produce QuickTime movies

There is an abundance of software packages to enable a lecturer to plot graphs of mathematical expressions. What these packages generally don't offer is a mechanism for changing a third variable of a two-dimensional graph in a smooth, continuous fashion.

One way to produce a controllable graph is to decide which variable you wish to alter and then make a QuickTime movie from a series of graphs generated within Mathematica, each one with a different value of the variable. The result is a graph, with a control bar beneath, which enables you to slide the value of the variable back and forth at will (or, if you let the movie loop continuously, the variable is made to change continuously in a repetitious manner).

Fig 1. Current and impedance for resonant circuit

Fig 2. Phasor diagram for an RLC circuit

Fig. 1 illustrates this effect. A graph is presented showing the changes that impedance and current undergo as a resonant circuit is scanned through a range of frequencies.

The graph is a QuickTime movie. The controller beneath it allows the movie to be played (each frame in succession), or moved through, by dragging the slide bar. The different frames in this movie represent the same graph, but plotted with increasing values of the quality factor, Qo. The result is a movie that can be scanned backwards and forwards providing a good "feel" for how varying Qo affects the shapes of the graphs.

The screen represented in Fig. 2 shows a slightly different application of the same idea. Here a "vector phasor diagram" has been constructed and is made to rotate in order to illustrate phase relations between different voltages in a circuit, the projection of the x-axis being an important feature for students to focus on.

3.2 Using HyperCard to produce focused simulations

Writing a simulation program just for one or two lectures might appear to be a daunting task. However, software environments such as HyperCard, SuperCard and ToolBook (5) make this quite manageable, remembering that the result is not intended to be an accurate, student-proofed simulation for general use, but a visual representation of an idea.

Producing a presentation using any of these environments also offers the advantage of being able to package the simulation, together with movies of graphical functions, still-pictures and video, into a sequence ready for lecture presentation.

Figure 3. Circuit simulation

Fig. 3 shows a screen image from a simple simulation which uses bar graphs to illustrate the voltage and the power dissipation in different parts of a circuit. The "sliders" on the left and right of the screen allow the values of resistors to be varied, thus causing the bar graphs to change according to voltage and power at various places in the circuit.

Although the simulation presents only elementary concepts in circuit analysis, a large number of second year physics students were unable to predict correctly what would happen to the power dissipated at the output of the circuit as the output resistance was increased from the value shown. The ensuing discussion was vigorous! 20880471">

4 What are the Requirements?

If multimedia presentations of the type described above are to be used in lectures, then we need to consider what is required for their production as well as what is required within the lecture theatre to enable them to be used effectively.

4.1 Production requirements

Commercial presentation software

One approach to setting up multimedia material for use in lectures is to employ a commercial presentation package such as PowerPoint (6). Packages like this one enable you to construct high quality, colourful displays incorporating pictures, diagrams and QuickTime movies. There are, however, limitations to this kind of presentation.

One limitation is that QuickTime movies imbedded in PowerPoint are not controllable--other than to start them playing. This removes much of the value of being able to "drag" through them forwards, backwards, slowly and quickly.

Another limitation is the lack of programmability. Whilst the screen can be made to build up nicely, one heading after the other, there is little other animation or calculation that can be employed on-screen. Some applications can be launched from within a screen, but these are very few.

If this type of package is to be used for a complete lecture presentation, then, of course, it has the advantage of a very clear presentation of text and diagrams, as well as the ability for students to obtain printed copies from a network to supplement their own notes. However, such an "all electronic" presentation removes much of the dynamic aspect of lecturing: scribbling comments, numbers and freehand sketches on an overhead transparency; jumping around a large diagram on a blackboard; constructing and deconstructing diagrams and workings during problem solving.

There needs to be a careful evaluation made here of a precise, clear presentation on the one hand and a more dynamic, lively presenter on the other. The two need not be exclusive.

Scripting environments

Scripting environments, such as HyperCard (Macintosh), SuperCard (Macintosh and PC) and ToolBook (PC) enable you to construct a sequence of screens for a lecture, each containing text fields, buttons, diagrams and animations. Since these environments support programming scripts, you can also produce simulations, carry out calculations and have full control over QuickTime movies.

Greater expertise is required to use such environments, but once a template is set up, the production of a series of screens for a lecture is quite straightforward. They have the advantage of enabling other programs, such as simulations, to be launched from within them such that when you quit, you are returned to your lecture series and can carry on with the sequence.

Hardware

All of the software mentioned so far runs satisfactorily on mid-range machines (eg. Macintosh LC III and 80486 PCs, upwards). However, since moving electronic colour images taxes computers heavily due to the immense data sizes involved, for development, a computer with fast graphics is advisable as well as plenty of RAM. Digital movies, whether they be animations, graphs or video, can occupy vast amounts of hard disc space. Data compression will reduce this significantly. If videos are to be displayed, or still photos, then appropriate hardware will need to be on hand to capture the images before compressing them to disc. This means a digital frame-grabber for videos and flatbed or slide scanner for photos.

4.2 Lecture theatre requirements

The design of lecture theatres equipped for multimedia use will have a great influence on whether lecturers take up the challenge to use them, or not.There is some advantage in having the projection screen is located in the corner of the theatre, rather than overlaying the blackboards or overhead transparency screen in the centre of the front wall. This might appear to be a trivial point, but it is significant in the possibilities that such theatres offer.

For a lecturer who makes significant use of blackboards or overhead displays during a lecture, those facilities are still there and can still be used in the traditional manner. The projection screen is now also available to be used in addition to the other boards, without the long delay while motorised boards are lowered in front of the black/white board. ="B_Toc321063106">

5 Interactions in Lectures

It is not sufficient to introduce the kinds of presentations discussed above without giving thought to a rationale for their adoption. The real challenge is to try to engage students more effectively in their learning within a lecture setting. If we display a pretty picture, then we have done no more than that--motivating at best.

However, if we can present something on-screen which we require students to think about, make a prediction about and then watch and explain the outcome, we stand a good chance of engaging their minds actively rather than them passively copying down notes.

In a small lecture group this will cause increased discussion. This is good and highly desirable for students' learning. However, it will mean rethinking the content of lectures as not so much will be covered in a set time. This is not a negative point, as we so often confuse "my coverage of content in a lecture" with "student's learning of content in a lecture." Very different things!

In larger lecture settings, it might not be possible to engage students in an active dialogue. However, they can be asked to predict to themselves, or to the person next to them, the outcome of a demonstration. The mere fact that they think before they are shown, improves the chance of them grappling with the concept being presented.

6 Conclusion

Experience during the last two years has shown that the use of such "cameo" pieces in lectures are very well received by students and help to develop more interaction and activity during the lectures. The extent of effort required for their production is more akin to lecture preparation than software development, although this still represents a considerable amount of time.

These applications of multimedia to lecture presentations are highly interactive and stimulating and offer various ways in which these media can help us to change and improve our teaching efforts.

7 References

(1) Wolfram Research, Inc., Mathematica, Champaign, 1988.

(2) Apple Computer Inc., QuickTime, Cupertino, 1989.

(3) Allegiant Technologies, SuperCard, San Diego, 1995.

(4) Apple Computer Inc., HyperCard, Cupertino, 1989.

(5) Asymetrix Corporation, ToolBook, Bellevue, 1992.

(6) Microsoft Corporation, PowerPoint, USA, 1992.

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These pages are maintained by Jon Pearce ( jonmp@unimelb.edu.au), Department of Information Systems. The opinoins on them do not necessarily reflect those of the University of Melbourne. Tel: (613) 8344 1495 Fax: (613) 9349 4596. Last update: September 16, 2003 .