Talk About Teaching - C. J. McMahon, Jr.

Talk About Teaching


Technology in Teaching


by C. J. McMahon, Jr.

   Suppose that you, as an automotive expert, are given the task of 

explaining how the basic parts of an automobile work to a student with a 

good high school education. You want to do this with maximum 

effectiveness in the minimum time. You quickly realize that a chalkboard 

is inadequate and that you need to employ visual aids, like diagrams and 

photographs. Ideally, you would want to use animated illustrations of 

the various parts of the engine, transmission, drive shaft, steering, 

brakes, etc., perhaps along with photographs and video clips. At the 

moment, there is no way to do this, but in the brave new world now 

almost upon us, you could load a CD-ROM into your laptop computer (color 

screen, of course), let the student play it, and then be there to answer 

questions and elaborate on whatever points need more explanation.

   The need for this kind of teaching abounds in many areas of pure 

and applied science. As a "high-end" educational institution, our 

challenge is to be at the leading edge of teaching with maximum 

efficiency and effectiveness. That is, in the limited time available for 

any given subject we need to impart the maximum amount of knowledge and 

understanding at the highest possible level. If we succeed, we will 

continue to attract highly intelligent students willing to go into debt 

(along with their parents) to study here. The way to succeed is to take 

advantage of the technology now available, technology which will be part 

of routine teaching within the current decade at any institution at the 

leading edge.

   Our introductory course in materials science has been a good test 

bed for the development of techniques for teaching about complicated 

systems which are completely unfamiliar to the average beginning 

student. The aim of the course is to provide in one semester for any 

undergraduate with a decent high school education a functional 

understanding of the discipline, which essentially involves the 

relationships connecting properties of materials (i.e., metals, 

ceramics, polymers, composites, and semiconductors) with their 

structure, ranging from the electronic level to structures coarse enough 

to see with the naked eye. We have just finished a seven-year 

development effort, which culminated in a new textbook in which we 

reformulated the traditional list of topics in a way that provides a 

student with a familiar conceptual framework. Dividing materials into 

those used to build structures and those used for devices, we use the 

bicycle and the Walkman as our paradigms. We have found that we can not 

only improve greatly on the students' understanding and retention  but 

also raise the level of the course to a considerable degree.

   While we were in the middle of this effort, it became apparent 

that it would be necessary to develop better ways to overcome the 

barriers to understanding of topics that require students to visualize 

complex phenomena, like the operation of the parts of an automobile. 

Many of the phenomena of interest involve physical motion or things that 

evolve with time. We found that static illustrations are inadequate to 

convey an accurate mental picture of the processes involved. This 

realization came from a number of informal review sessions, usually held 

before mid-terms or final exams, in which students were encouraged to 

explain their understanding of various topics. The fundamental problem 

is that, when an instructor attempts to convey a complex mental picture, 

he has no way to see the image that the student has received and the 

student cannot see the image that was being transmitted.

   The solution to this problem is obviously to use a computer 

monitor, so that the dynamic image of the phenomenon or process is 

visible on the screen to both the instructor and student simultaneously. 

This is analogous to a high-tech chalkboard or slide projector; the 

essential difference is that the image can be made to move. We have 

found that this method produces an extraordinary improvement in the 

speed and accuracy of comprehension of complex topics. The effect is at 

least as great as one would find from the use of normal (static) 

illustrations, compared with no illustrations. A good example is found 

in the series of animations depicting the plastic shearing of crystals 

by the motion of defects called dislocations. In about forty minutes, we 

can convey an accurate understanding of this set of phenomena, which are 

normally considered too complex for an introductory-level course. 

Without the animations, it would take at least twice as long to "cover" 

this subject, and we would have no idea of how much was comprehended by 

any particular student. A clear understanding of the mechanisms of 

plastic deformation is essential for one to learn how materials, e.g., 

in bicycles are made strong. Thus, a major part of the course is on 

shaky ground if the student does not understand the basic ideas of 


Beyond `Shovelware'  

   The improvement in communication allowed by the animations is 

analogous to the advance provided by cinematography over still 

photography. Once animations are used, it becomes unthinkable not to 

continue to use them on a more extensive scale. Thus, they define a new 

state of the art. The problem then becomes one of assembling the money 

and talent to produce computer-based dynamic images on an ever-expanding 

scale. This involves the right kind of computer (e.g., a Quadra AV-type) 

with lots of memory, software like Macromedia Director, video-editing 

hardware and software, a machine to make CD-ROMs, etc., along with an 

instructor who is an experienced teacher and has a clear understanding 

of the images that need to be produced and one or more assistants who 

are capable of using the equipment to produce the images. All this 

involves the acquisition of new resources, or the re-allocation of 

present resources, at a time when financial pressures are increasing. 

However, there is really no choice for a university that wants to be 

competitive in the long run, and the long run will be measured in years, 

not decades.

   It needs to be emphasized that the type of activity being 

described here is separate from the ideas being discussed with regard to 

distance learning via the Internet, the so-called virtual university. We 

are speaking here simply of a logical extension of what already goes on 

in university courses, using new hardware and software. Producing this 

type of CD-ROM is essentially similar to authoring a textbook of a type 

that needs a lot of technical assistance. That is, it needs the 

participation of specialists who keep up to date in a fast-developing 

new field. Because of this, carefully thought out institutional support 

would be of great benefit. It would be helpful to have a centralized 

resource at this University to provide this. The Center for Advanced 

Instructional Media at Yale might be an appropriate model, and the 

Annenberg School would seem to be a natural home for such a center, 

since what is involved here is essentially an advanced form of 


   Even though we at Penn would be a bit late arriving at the 

starting gate, we would not be very much behind the state of the art. 

The rate-limiting step in making a useful CD-ROM is the creation of 

useful content. Although the number of CD-ROM titles has grown in the 

past two years from under 200 to over 2000, the vast majority of titles 

are derided as "shovelware," for which images and text have been 

assembled from whatever lay at hand, just to get a product on the 

market. Since the creation and conveying of intellectually significant 

content is our main activity, we are in a clear position of advantage in 

entering this new field.

This article is the sixth in a series developed by the Lindback Society 

and the College of Arts and Sciences. The author is professor of 

materials science and engineering in the School of Engineering and 

Applied Science. 


Volume 41, Number 25
March 21, 1995

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