AUC Academic Conference 'From Virtual to Reality' The University of
Queensland 1996AUC Academic Conference 'From Virtual to Reality' The University of
Queensland 1996
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Paper Title:
Research-Based Multimedia Tutoring
Presenter:
Rod Lambert, Massey University
Authors:
Rod Lambert and Jason Bartlett
Department of Physics, Massey University
Keywords: Multimedia, Physics
Faculty area: Science - Physics
Introduction
The teaching of first-year university physics can be a very frustrating process. Those of us involved in such teaching think, in our more cynical moments, that we are teaching the unknowable to the unwilling. The reasons for this are many and not easy to discover, which often leads us to take the easy option: blame the customer. Here we are, trying very hard to get the students to understand and they don't, won't or can't! Whereas there will always be the requirement that students must bring motivation to their studies, there is also more that we can, and should, be doing. We can be guided in this by recent research into student difficulties in understanding physics. This research has been informed by studies in the more general field of science education and by research in cognitive psychology (Many useful references are contained in the following citations: ?(1, 3)?). Briefly, the hard fact of the matter is that 90% of the students in front of a physics lecturer in any big first-year university class are not going to be physicists and probably do not think and understand in the same way that the lecturer does. They also bring with them a grab bag of mental models of how the world works, many of which will contain contradictory elements and which are very resistant to change. Simply telling the students that they are wrong and that we are going to "give" them the "real oil" is totally ineffective in changing fallacious mental models. For example, van Heuvelen has remarked that in his study of a typical introductory-level lecture class, 20% of the students entered the first semester of the course as Newtonian (as opposed to Aristotelian) thinkers. At the end of the first semester, after his best teaching efforts, the fraction rose a mere 5% from 20% to 25% (quoted in ?(3)?). Our task, then, is to find ways of presenting material that non-physicist students find useful and that help them to develop real understanding.
Current editions of first-year university physics text books are offered with a plethora of (alleged) teaching aids among which are computer-based tutorials. These are usually collections of drill exercises with minimal help available to the student. The tutorials do not seem to be based on research into the learning and conceptual difficulties students experience in coming to grips with physics.
Perhaps the most important element of the search for better ways of teaching is to discover how best to change those elements of students' mental models that must be changed but that are resistant to such change. The work of the Physics Education Group at the University of Washington in Seattle has thrown much light on this area ?(1)?. This group has shown that in order to convince a student of the need to change a mental model it is necessary to guide the student to a situation where there is a conflict with what is observed by the student and what the student's mental model predicts. The student is then helped to resolve the conflict by amending the model. The process needs to be repeated several times to "bed-in" the changes and to make sure they become a functional part of the student's understanding. One of the areas of physics that the Seattle group has investigated is student understanding of electric circuits.
Most students are first introduced to electric circuits in elementary school through the use of light bulbs and batteries. Despite this early introduction, many students at tertiary level are unable to deal with simple dc circuits as the work of McDermott and Shaffer? has demonstrated ?(2, 4)?. These authors have shown that the underlying conceptual problems can be overcome in a laboratory-based curriculum with a high instructor-to-student ratio ?(4)?. Some success has also been achieved in the more common lecture-based courses when there are weekly tutorials that emphasise the development of qualitative reasoning skills. The essence of the teaching strategy employed is "elicit, confront, resolve" ?(4)?. Students are challenged to predict the outcomes of simple experiments. When a student's prediction fails, the student is encouraged to form new conceptions that lead to accurate predictions. We set out to develop a computer-based tutoring module that would function in a similar way to that advocated by McDermott and colleagues for human tutors.
Some of the issues that need to be addressed are: the current provided by batteries depends on what is connected to the battery; electric current carries energy from the battery to the rest of the circuit; energy, not current, is dissipated in light bulbs; current divides at a circuit junction; as much current gets back to the battery as left it. We have attempted to address these issues by using the exemplary circuits described by Shaffer and McDermott ?(4)? and added three more circuits of our own.
Description of the tutoring module ("Lighting up Circuits")
Environment
Our development environment was Hypercard 2.2 running on a Macintosh Centris 660AV. Digitisation of video was done with the on-board digitiser running under Fusion Recorder 1.0. Later polishing was done on a Power Macintosh 7100/80AV. Post-processing of the video clips was done with Adobe Premiere 4.0.
Students have access to the program at a kiosk in the Physics Department foyer. The kiosk contains a Power Macintosh 6100-60 (out of sight) and a standard 14" monitor behind a glass panel. The students have no access to a keyboard-all interaction is performed via a trackball mounted on the front panel of the kiosk.
The Philosophy
We decided that we should do the easier things first and that these were the "elicit" and "confront" parts of the teaching strategy. The "resolve" part of the strategy appeared to require more intelligent interaction than we could see ourselves programming into the module. The student is presented with a schematic circuit diagram consisting of an ideal battery and two or more identical light bulbs. The student is then asked to rank the bulbs in order of brightness ("elicit") following the technique of McDermott and Shaffer?. Correct answers receive positive feedback (a burst of applause) as well as a video still of the connected-up and glowing circuit. Wrong answers produce a statement that the selected ranking is not the same as the experimental evidence ("confront") and the student can then choose to try again or to seek help before trying again. Thus the "resolve" part of the strategy is left largely to the student. To aid the student a little in the task of resolution, we have included some help screens in which we try to deal with some of the common misconceptions.
The Content
The circuit diagrams that are included in the module are shown in Fig.'s 1 through 3.
Fig. 1 Basic Circuits
For the circuits shown in Fig. 1, the student is asked to compare the intensities of either the two bulbs in series or the two bulbs in parallel with the single bulb ("A") and with each other. Success with these tasks leads to the circuits shown in Fig. 2. The student can select which circuit to work with. In these circuits, the student is asked to rank the bulbs in order of brightness.
Fig. 2 Intermediate Circuits
Fig. 3 Advanced Circuits
The third set of circuits the students can work with is shown in Fig. 3 and is billed as the set of "Advanced Circuits". Again, the task is to rank the bulbs in any one circuit in order of brightness.
Navigation
Students can, if they choose, work through the circuits in any order. However, the circuits are grouped as indicated in Fig.'s 1 through 3 and the basic navigation diagram at the start of the module as well as the naming of the groupings suggests an appropriate order for those who are using the module for the first time.
The help screens are available from anywhere in the module. They are context-sensitive in that the student is always returned to the screen from which help was requested.
Evaluation
An early version of the module was used by gifted high school students during our Winter School. The step from the circuits shown in Fig. 1 to those shown in Fig. 3 seemed to be difficult for these very good students. As a result, we included the collection of "Intermediate Circuits" shown in Fig. 2. Several other enhancements were added after consultation with an experienced high school teacher.
More extensive evaluation of the module has been difficult because of the kiosk setting. We are currently unable to provide access to the module in a tutorial or laboratory setting. It appears that the most useful and most easily implemented evaluation will be the "naturalistic observation" recommended by Waterworth ?(5)?. He contends that questionnaires and focus groups seldom bring out the full complexity of what multimedia users actually do. We hope to be able to try to watch (unobtrusively) students working with the module next year when a laboratory setting will be available to us.
The module automatically keeps a log of usage that includes circuits studied and a count of correct and incorrect answers. The module has been available in a kiosk computer in the Physics foyer since the start of the year but students were not directed to it until circuits were being discussed in lectures. After the announcement was made, the module was used 43 times and 143 attempts were made at completing at least one of the tasks, with an approximate 50% overall success rate. Very few users attempted the more difficult tasks, and most of those who did were clearly guessing. The help screens were used only 12 times. We found this puzzling until we recalled that one of our test group of high school students suggested that help screens are boring. We had thought that the comment stemmed from the fact that she was a physics student and was not in a lot of trouble in understanding the circuits. However, that help screens are boring may be a more widespread perception than we think. The use of them may require a high level of motivation in the user.
Discussion
"Lighting up Circuits" addresses many, but not all, common misunderstandings of electric circuits. One notable of misunderstanding that we did not tackle directly is that of student difficulties associated with reading circuit diagrams. Success with this module depends on the student having the ability to correctly interpret such diagrams. It may be that the high failure rate that we have observed in our kiosk data is attributable to misunderstandings in this area and not in the areas that we thought that we were addressing.
Many students cannot relate the formal layout of a circuit diagram to the much more casual arrangement of the real circuit. There is some help for the student in this in the module in that real circuits shown in the video stills are laid out in a very similar way to the circuit diagram. However, the student has to be successful in answering the question before s/he can see the still!! Catch 22!
Summary
A teaching module has been developed that aims to deal with well-documented student difficulties in understanding electric circuits. The emphasis is on developing qualitative reasoning skills. No calculation is required, in fact it is explicitly discouraged.
The module "Lighting up Circuits" is being prepared for commercial release. It won an honorable mention in the 1995 Computers in Physics educational software competition.
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References
1. McDermott, L. C. What we teach and what is learned-closing the gap. Am J Phys 59: 301-315, 1991.
2. McDermott, L. C., and P. S. Shaffer. Research as a guide for curriculum development: An example from introductory electricity. Part I: Investigation of student understanding. Am J Phys 60: 994-1003; 1992; erratum, ibid. 61: 81; 1993.
3. Redish, E. F. Implications of cognitive studies for teaching physics. Am J Phys 62: 796-803, 1994.
4. Shaffer, P. S., and L. C. McDermott. Research as a guide for curriculum development: An example from introductory electricity. Part II: Design of instructional strategies. Am J Phys 60: 1003-1013, 1992.
5. Waterworth, J. A. Multimedia interaction with computers: human factors issues. New York: Ellis Horwood, 1992.
Dr Rod Lambert,
Dept of Physics, Massey University,
Private Bag 11-222,
Palmerston North,
New Zealand.Phone: +64 6 350 4049 (direct) +64 6 350 4055 (Dept Office)
Fax: +64 6 354 0207Email: R.Lambert@massey.ac.nz
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