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The design and development of CAL materials in undergraduate science
Comput. & Graphics, Vol. 2. pp 241-247 Pergamon Press. 1977 Printed in Great Britain
THE DESIGN AND DEVELOPMENT OF CAL MATERIALS IN UNDERGRADUATE SCIENCEf D. M. LAURILLARD EducationalDevelopmentOfficeron the CUSC Project, Institute for EducationalTechnology,Universityof Surrey, Guildford, U.K.
(Receiced 24 Nocember 1976) Abstract--This paper describes the work of the project Computers in the UndergraduateScienceCurriculum(CUSC) which is supported by the National DevelopmentProgramme in Computer Assisted Learning,based in the U.K. The development procedure used by the project is described, and the preliminaryevaluation findingsare outlined. In particular, it is possibleto establisha few basic principlesfor the designof this kind of simulation,semi-structuredCAL package. Evaluationhas alwaysbeen an importantfeature of the project and here providesan accountof some of the learning gains identifiedso far.
The structure of the project
INTRODUCTION This paper describes the work of the project "Computers in the Undergraduate Science Curriculum" (CUSC) which is supported by the British National Development Programme in Computer Assisted Learning. The project was financed initially as a two-year feasibility study and in January 1976 received funding for a further two years of development work. The paper outlines the aims and methods of the project and describes the experience we have had in using CAL materials with undergraduate science students,
With three institutions involved, it is important to provide the means for frequent communication between their staff, if there is to be a genuine collaboration. Accordingly, there are three subject-based committees which bring together participating academics approximately twice a term, in order to generate and monitor the CAL packages which are in use or under development. Packages are usually developed by either one or two people from one institution in close collaoboration with colleagues from the other two. This continual involvement of other institutions in the development of a package is seen as being one of the most useful features of the project. Packages are inevitably less institution-dependent and therefore stand a better chance of transfer to institutions outside the project, which has already happened in two cases. Committees responsible for hardware/software, educational policy and transfer and dissemination of materials, were set up to co-ordinate the work of the project in these areas. They have enabled us to deploy the project's resources effectively according to its needs
D~RIFrlON OF THE PROJECT One of the two major aims of the project is to enrich the teaching, and more especially, the learning of selected topics in science by means of on-line interactive graphical displays. The use of graphics terminals was seen as essential in a science-based project because in the physical sciences the use of pictures or diagrams is often the most natural way to communicate ideas. We rely entirely on the interactive capability to facilitate learning, by allowing the student to interrogate the cornputer, or manipulate parameters of the system to obtain the results wanted. This allowed us to use low-cost installations instead of highly sophisticated systems required by a programmed learning approach, The other major aim of the project is to achieve the dissemination of teaching materials and methods beyond the institutions involved in their development, and for this too it is important that we use standard low-cost installations. CUSC is organised as a collaboration between three institutions: University College London, Chelsea College London, and the University of Surrey, and covers the three broad subject areas of Physics, Chemistry, and Biology. Some fifty members of academic staff are active participants on the project, including four heads of department. The project employs six full-time development staff, of whom three have primarily computing responsibflities and three concentrate on educational development and evaluation,
at any one time. The hardware set-up has been similar at the three institutions, using a dedicated mini-computer and, initially, two graphics terminals, to expand to six at each site during this year. The shortage of equipment has restricted student use, but nevertheless we have been able to test some thirty packages, each with an average of about fifteen students.
Educational philosophy As far as CUSC is concerned, a CAL package cornprises a computer program and a written student guide, and is designed for either one or two students to use at a graphics terminal during a one-hour period. As the aim is to enrich learning, the topics covered are generally taught elsewhere in the course so that the students already have some understanding, but use the computer to increase their knowledge or develop their under-
fThis paper was presented at the Seventh Conference on Computers in the Undergraduate Curricula 14--16June 1976,held at the State University of New York at Binghamton.
standing further. Typically, a package simulates a physical system and allows the student to investigate it by changing parameters within the system, or by using the
241
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D.M. LAURILLARD
program to explain a phenomenon, or achieve a certain result. The way CUSC has been set up has inevitably had an important influence on the way it has developed and the kind of material it produces. Most significant, perhaps, is the fact that early on, it established a hard core of enthusiasts and has been able to expand by drawing in new people who have been excited by what they have seen happening in the project. Apart from collaboration, no special demands or directives are imposed on the participating academics, so that people with widely differing educational ideas and interests have been attracted to work in CUSC. The project began cautiously in its teaching philosophy, adopting no particular theoretical stance, but rather relying on an empirical approach to the development of materials, with considerable emphasis on formative evaluation. The high level of communication between participants has given us ample opportunity to benefit from our mistakes, so that while we have found that the early caution was justified, the pooled experiences since then have allowed the project to explore several different approaches to the use of the graphics terminals (see section 4 of the Appendix). Thus CUSC started small, but with the ability to continue expanding as more people become interested, Its non-directiveness means that widely differing types of materials can be developed, but its collaborative style means that they should all be widely usable.
TUg V~VgLOl~rr OF ~ G PACKAGES An important factor in the effective design of educational packages is the development procedure used, and CUSC has taken care to establish an efficient and workable procedure. This section outlines the rationale behind it, and describes how the procedure operates,
Questionnaire to staff and students Initially an open-ended questionnaire was sent to both staff and students likely to want to use CAL materials, with the aim of identifying students' academic needs in the different subject areas. Replies have been as general as "how to solve differential equations," or as specific as "how to interpret term symbols". Perhaps surprisingly, staff and students were in broad agreement as to the topics that present greatest learning difficulties. Results from the questionnaire have been helpful in the selection of topics for development as CAL packages, although not all student problems are best served in this way, and in some cases, alternative teaching methods have been found more appropriate,
Subject committee All three institutions are represented at each of the subject committees, and it is here that the decision to develop a CAL package on a particular topic is made. The decision is based partly on the information provided by the questionnaire, and partly on the members' experience of teaching those topics. The responsibility for initiating potentially useful packages therefore rests with these committees,
Initial draft of the package The initial design of a package plays a relatively minor part in its development overall, as the responsibility for its effectiveness is taken by the subsequent formative evaluation. It is helpful to begin with as good a design as possible, but since we expect several changes to take place during evaluation, we do not attempt to perfect it before student trials begin. However, a number of principles of good basic design have evolved, and these are reported in the next section.
Student trials When the first draft of a package is completed, student trials begin, and these are organised to allow changes to be made to the package between successive trials, each trial using three or four students. We use small numbers of students on each trial because we are attempting to design an effective package that is moulded to the needs and abilities of the students. The formative evaluation during these trials requires a number of detailed feedback measures that include ohservation schedules, feedback forms, interviews, and students' performance on the package. All these are best done with small numbers, and it would be unprofitable at this stage to attempt the kind of statistically valid description of student use that would necessitate large student numbers. During early trials, it is usual for an academic tutor to be present to assist students where needed and to supplement the deficiencies of the package. The ensuing interaction between students, computer and tutor is then recorded in detail (manually, for easier analysis, using the observation schedule) and this provides the main basis for future changes. The advantage of this procedure is that the human tutor is highly flexible and can respond to student difficulties by exploring, for example, a variety of explanations until he discovers those that the students find helpful. He can also provide hints and ask questions that lead the students to explore the subject matter more deeply for themselves. The trial session is therefore an approximation to the optimal learning situation for those students. By using a procedure that converges on a successful teaching situation, we can exploit that success by incorporating the teaching strategy used into the package, wherever this is possible. It is a highly labourintensive procedure, but that effort is an investment that reaps the reward of an effective and well-designed package. These results from observation are supplemented by interviews with students, and by analysis of their performance, obtained either from computer monitoring or from written work done during the session. Four or five such trials are usually sufficient to bring the package to a state where students can run it on their own, and further, usually minor, changes can be based on the continual monitoring done both by the computer, and by feedback forms administered to the students after each session. This reduced level of monitoring is maintained throughout the later stages of development of the package, both in the originating institution and in the institutions to which it has been transferred.
The design and development of CAL materials in undergraduate science EVALUATIONFINDINGS The experience gained in two years of the project has contributed towards a number of general findings related to the use of CAL in teaching science. The results outlined below constitute a distillation of this experience, and while they are not in any sense prescriptive, they have been very useful in forming a basis for further development and investigation of the issues that seem most important for the success of CAL, as interpreted in the CUSC project.
243
For many teachers, therefore, CAL is now seen not as an expensive luxury, but as one solution for a number of quite disparate educational needs. SYMMETRY
OPERATORS
e I
z
The use o f C A L
The two most obvious advantages of the computer in v its use in teaching are (i) its capacity to handle data, and (ii) the interactive mode of communication. The first enables the computer to simulate a large number of physical situations; the second enables the student to interrogate this information source and generate required data, thus forcing the student to be an active participant rather than a passive recipient. We have found that the NEXT OPERATION ? !~1 need for CAL first becomes apparent when the teacher realises these features of the computer can be exploited Fig. l(b). in order to go beyond the normal resources of a university science department. For example, a package simulating a genetics experiment ("COEXIST--an exzP c: periment in population dynamics") allows the student to ErF Z = use the computer as though conducting an experiment 3 25 ..... that would, in reality, take years to complete. '-"--~. :: ::.../...-:...:::):i).:../:: : ?-:.:-..../.++++,...Teachers have discovered many similar ways in which ......::"+++++++ : : ....... : • .•.".++~#'##.###~####+ .....I the computer can help them extend their teaching into : .:():+T++~ ~ .... more interesting areas than before. But while this was o Nr.* ':'...::'.):~J~Wse~s-~ , . . . . . . . -..... often their reason for joining the project, having seen the ....... .........++##=sn~..++###s## I ........ ................... advantages of CAL for this purpose, many then pro . . . . . . . . : : .-..-++#####...'+++++++ I ,,:" ceeded to look for areas where it may improve upon ....... ..-...-++++..... ,, ... traditional teaching methods. One example is a package ~ : ::(.".:-. ...... ("GAUSSI"--Fig. la) that allows the student to practise the technique of analysis of Gaussian mathematical operations. Another example is a package ("PTSYMI"-.2 . P L E A S E PO:=JIT I,:,H ,::,_,R'.--:,:,~: Fig. lb) that generates any required symmetry operation Fig. l(c). and therefore gives the student greater scope for improving understanding than would be possible with a selection of models. ~ : ¢
ENTER EM, W, KM BAND 1 ? 50, .15,1 3
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OEPTH= 217 ELECTRON VOLTS HALF WIDTH == 1 BOHR RADII P#RTICLE MASS == 1 ELECTRONMASSES TRIAL ENERGY = - 4 0 ELECTRON VOLTS PARITY I S EUEN
Fig. l. Examples of screen displays for packages. (a) Gaussian plots: the user enters parameters of the two Gaussians, at-
"
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t¢ , ; t t t ;i 1.3 t.,I t.~ I.E t.7 t.l~ t.~ z Fig. l'(a),
tempting to make the envelope fit experimental data. (b) Point symmetry: the user selects an operation on the flag, and the resulting reflection or rotation is displayed. (c) Atomic orbitals: the user selects a cross-section of the orbital and the correspondingwave function is plotted. (d) Schroedingerequation for a particle in a one-dimensional square well: The user selects parameters for the wave function, which is then plotted.
244
D.M. LAURILLARD
The heed for graphics It is imp,.rtant for CUSC to be able to justify its use of graphics t~ninals as, in the U.K. at least, their value has not yet been proved. They are seen to be particularly useful in mathematical modelling, as this is a notoriously difficult area for student understanding. It is a creative and dynamic process, requiring both imaginative thought and feedback in order to control the imagination. With most students it has been easier to stimulate and develop imaginative thought in connection with pictures and diagrams than with numbers and formulae. This calls, therefore, for graphics displays, If the computer is needed in teaching for its datahandling or interactive capabilities, it follows that graphics will be needed whenever the subject matter is best communicated by diagrams. This is such a common occurrence in science subjects that even those few of our packages which have used teletypes, have still generated the data in graphic form. From the experience of the last two years, therefore, we feel the use of graphics has been well justified,
Package design From the experience gained in the formative evaluation of more than thirty packages, a number of basic principles of design emerge. These do not themselves ensure successful packages, because success will depend also on such package-specific details as wording, terminology, types of diagrams used, etc., but they have acted as useful guidelines,, and as a way of passing on experience, Pre-package exercise. Students receive the written package guide before coming to the computer and are usually asked to complete some exercises linked to the computer topic. This is to encourage students to prepare '~ mselves for the theory contained in the package so they will be able to play a genuinely active role in operation of the program. The theory will not essarily be new to them, but we have frequently round that they need this preparatory exercise, even if only for revision. Introductory exercise. Most packages are designed for students to use unsupervised and in a self-directed style, This means that to get the most out of the package they need to know what options are available and how they may be operated. An introductory exercise consisting of a list of carefully written instructions that guides the students through the program acquaints them with all the Recognise and identify diagrams Rehearse difficult procedures Understand a mathematical model Visualise the subject Understand the behaviour of parameters Develop a problem solving strategy Perform a meaningful experiment details of the package and how it works. The remainder of this work on the package can then be genuinely
self-directed, once they are familiar with what is available. Suggested exercises. Although it is important to allow the students the freedom to work through a package in their own way, there should, nevertheless, be a stated goal for them to aim at. Without this, completely undirected work tends to result in inefficient use of the package for most students. In "Rutherford scattering" for example, students can generate particle trajectories by specifying values for the impact parameter and velocity. Without the suggestion that they look for cornbinations which give, say, small scattering angles, there was a tendency to simply "see what happens i f . . . " rather than to think about what should happen. Interaction with the computer. Students working within CUSC are, on the whole, naive computer users, and we therefore feel it is necessary to make the interaction with the computer as unobtrusive as possible. The precise details of design are, of course, very packagedependent, but after much experimenting a favoured form has emerged. Once the program is running, the computer asks simply NEXT? and the students may reply either with a number to select an option, or with a letter and number if they wish to change a parameter (see Fig. 1). This very simple form is all that is needed for a surprisingly high number of quite complex programs and has the great advantage of being very straightforward, even for the most naive computer user.
Student learning gains As described earlier, we have used an empirical approach to the development of packages using repeated student trials to mould the package into an effective teaching method that takes account of students' needs and abilities. We have found, therefore, that it is quite common for the aims of a package to adapt to those aspects of a topic that makes best use of the computer according to what the students need. For this reason we have not attempted any controlled test of the effectiveness of CAL in comparison with other learning methods, which rarely have the same aims. Learning gains have therefore been assessed with reference to the performance of students on exercises within the package, by their own reports, and by the tutor's reports of what the student has achieved. A summary of the improvements gathered in this way demonstrates the variety of capabilities of CAL. A package can help them to carry out the following (examples of actual packages in brackets): (Atomic orbitals, Fig. lc); (Genetic mapping); (Schr6dinger equation, Fig. ld); (Phasor diagrams); (Rutherford scattering); (A free-fall problem); (Population dynamics). To take two of these and look at them in some detail will give some indication of how the project works.
The design and development of CAL materials in undergraduate science
245
A package that illustrated the concept of moment of inertia began as a more advanced package that used moments of inertia to study the idea of a centre of percussion. It became apparent in the early stages of evaluation that the students needed help with their understanding of the concept of moment of inertia before they could go on to apply it. The original package was quickly replaced by the required package and it has developed from there into one of the most successful packages produced. It is interesting to note that this incident occurred in the early stages of the project before we had circulated the questionnaire and was an example of how staff and student views can differ on what is needed, Several packages have been developed to simulate a practical experiment (e.g. population dynamics), often one that is too difficult or too expensive to do in the laboratory. Student comments on this type of package have strongly emphasised two major advantages: firstly, it cuts out tedious manual operations and allows them to concentrate on theory, and secondly, it always works! The success of these packages has led to the possibility of some future packages being designed to replace existing laboratory experiments. This idea has met with strong resistance from teachers who feel that students should be able to practise experimental skills, But some laboratory experiments have, as one of their aims, the greater understanding of related theory, and it
teachers preferred to write their own accompanying guide. As it is essential that the experience gained during development of the guide should not be lost, we now attempt to transfer the ability to rewrite student guides effectively. This is done by including in the documentation copies of all student guides that have been developed, and thoroughly tested, together with a teacher's guide which outlines the rationale behind them, and the possible uses of the computer program, which will generally remain unchanged. There is little emphasis within CUSC on producing a final polished product for transfer to other institutions. The aim is to transfer experience and ideas with the hope that this will be built upon and extended by the receiving institutions.
is here where, as the students point out, the computer does better. CAL is likely, therefore, to provide an alternative to at least some aspects of laboratory work. The student learning gains described in this section have been predominantly of higher order and these are more difficult to test than gains in, for example, factual knowledge. We have used pre- and post-tests on some packages, but these can assess only a small part of their educational value. We shall therefore continue to rely on staff and student reports, and student performance on exercises to assess learning gains.
Acknowledgements--The author wishes to thank all the academic
TRANSFEROF PACKAGES One of the most tangible successes of the project so far has been the level of transfer achieved. More than half the developed packages have been used in at least two of the participating institutions, and two have already transferred outside the project. The most important factor contributing to this success is the collaboration between institutions in the early stages of design of a package, because it is there that local idiosyncrasies are avoided. Collaboration also means that there is pressure on the designer to keep the package as widely adaptable as possible, and as a result, many of the transferred packages have been used for a variety of different teaching purposes. Good documentation is an important part of the transfer process and this, like everything else, has been subjected to experimentation to achieve the appropriate format. We originally thought that after extensive development, both the computer programme and student guide should remain unchanged after transfer. However, we discovered that the student guides rarely transferred:
CAG VoL 2, No 4--D
CONCLUSION The work described here is continuing and this paper should be seen as an interim report. We still have a long way to go, but already the evidence is persuasive: experience has shown us that interactive graphics are technically and economically feasible in undergraduate teaching, and the educational value of our use of CAL is becoming increasingly demonstrable as more and more academics find it is a worthwhile investment of their time and effort. Response from both staff and students suggests that CAL has a healthy future.
staff,developmentofficers, and students, who have taken part in CUSC,for their help and hard work, and to the National DevelopmentProgramme for encouragement and support.
APPENDIX 1
Pl0 Momentsof Inertia .StudentsNote* 1. ~ODUCT1ON This computer package is designed to give you a better understanding of the factors that affect the moment of inertia of a lamina of uniform density; both theoreticallyand intuitively.The program allows you to specify (draw) the shape of a lamina on the screen, by using the READ CURSOR key. Using the various optionsyou can verify to your own satisfaction the results you obtainedin the ore-package experiment. 2. Pre-requisite Beforerunning the program you must have studied unit 9 in the Particle Mechanics course. You must also have completed the exercise above to your own satisfaction. 3. Theoretical background The expression for the moment of inertia of a rigid body is /.
I = ~ r 2 dm J
where r is the distance from the axis of the mass element din. The 3. axis theorem for a lamina is I, = Ix + I,,
wherex, y, and z are mutually .1. axes through one point in the lamina,and the z axis is 3_ to the lamina.
246
D . M . LAURILLARD
(2) The program assumes mass/unit area = 1. (3) If you accidentally press the reset key while using the cursor you will lose the cross hairs. To regain them, (a) press line switch (light goes out), (b) hold CTRL key down and press/key, (c) press line switch 0ight on).
The ]J axis theorem for any body is Io = f~ + Md~
where do. is .L distance between the chosen axis and a Jt axis through the centre of mass, L is the moment of inertia about the centre of mass,
(b )
~
,~_?2.~
Notes on options: *For options 1, 2 and 3 you must use the read cursor key and the cursor to tell the program the point that you wish to specify as fixing the axis. *Option 4 needs two points to specify a straight line. In all cases the point or line which represents the axis will be labelled from 1 upwards, as will their moments of inertia. For example to draw a triangle:
=._.....• ~ • :~ Io
4.3 Options: OPTION? I gives the moment of inertia about an axis parallel to the x axis.* 2 gives the moment of inertia about an axis parallel to the y axis,* 3 gives the moment of inertia about an axis perpendicular to the plane of the screen 4 gives the moment of inertia about an axis lying in the plane of the screen at any angle.* 5 clears the screen and redraws the figure last specified. 0 clears the screen ready for another figure.
Ic
Useful moments of inertia: (d) I,
--1
2
TO move the cursor up, down, along or across, press keys marked with the arrows ~ , ~ . ~ or ~ respectively
=3 Ma
1 2 -}"' Y = 3 ~:~
To produce the first point position the cursor Ot this point and press the Read Cursor ( R C ) k e y . A small dash will mark the f i r s t corner t h a t you choose.
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2+b2).
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Reposition the cursor for *he next corner using the 'O. . . . . d' keys
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l i n e w i l l be d r o w n , j o i m n g up the f i r s t
and second p o i n t s
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4. The program 4.1 Log-on and run the program, Log-on at a graphics terminal and run the program"MOFI" (notes on how to do this are on the wall in the CUSC laboratory 4AY21). 4.2 Draw a lamina. This is very easy once you get the knack, The box on the screen represents an area 100 units x 100 units, This is the area inside which you draw the lamina. The corners of the lamina are specified in turn by moving the cursor (the feint crossed lines) to the relevant point, going round the circumference of the lamina, and pressing the read cursor key. When you have specified the last point, press the HOME key followed by the READ CURSOR key. Notes: (1) There are sometimes points on the screen that cannot be read by the R. C. key. If you choose one of these points by accident, the message PLEASE RE-POSITION THE CURSOR will be printed on the screen; re-position the cursor in a slightly different place and continue. Sometimes this causes an INPUT ERROR and will stop the program. To reprint your figure, type RUN3 and press RETURN.
YOU now have t o s p e c i f y the ~ast p o i n t on the triangle Move t h e c u r s o r to t h e p o s i t i o n of t h e t h i r d corner. Press t h e R.C. key.
The line joining the previously specified point to this new one will be drown
you now only hove to press the HOME key to,owed by the R.C. key, and the p r o o r a m wi, complete the triangle for you zt w,, then ask you for your opt,on
OP~,ON]~...f]/ ]
5. Suggested exercises 5.1 Draw the lamina used in the practical. Use the program to check your answers to the questions in this pre-test. 5.2 Draw a square or rectangle. Check: (1) t h e / ~ axis theorem; (2) the .L axis theorem; (3) the expression derived analytically for its moment of inertin (see section on Theoretical Background), 5.3 Draw a figure. Find the two mutually perpendicular axes for which the moments of inertia is a minimum. Is this what you would expect?
The design and development of CAL materials in undergraduate science 5.4 Plot the momental ellipse. (This is extra to your course syllabus.) Find the moment of inertia of a rectangle about several axes (approx 10) in the plane of the lamina passing through the centre of mass (see diagram). Mark a length along them proportional to one over the square root of the moment of inertia. These points should lie on an ellipse--called the momental ellipse.
247
(e) X / ." . . . . ~ ~ ~ -
/
\
THE DESIGN AND DEVELOPMENT OF CAL MATERIALS IN UNDERGRADUATE SCIENCEf D. M. LAURILLARD EducationalDevelopmentOfficeron the CUSC Project, Institute for EducationalTechnology,Universityof Surrey, Guildford, U.K.
(Receiced 24 Nocember 1976) Abstract--This paper describes the work of the project Computers in the UndergraduateScienceCurriculum(CUSC) which is supported by the National DevelopmentProgramme in Computer Assisted Learning,based in the U.K. The development procedure used by the project is described, and the preliminaryevaluation findingsare outlined. In particular, it is possibleto establisha few basic principlesfor the designof this kind of simulation,semi-structuredCAL package. Evaluationhas alwaysbeen an importantfeature of the project and here providesan accountof some of the learning gains identifiedso far.
The structure of the project
INTRODUCTION This paper describes the work of the project "Computers in the Undergraduate Science Curriculum" (CUSC) which is supported by the British National Development Programme in Computer Assisted Learning. The project was financed initially as a two-year feasibility study and in January 1976 received funding for a further two years of development work. The paper outlines the aims and methods of the project and describes the experience we have had in using CAL materials with undergraduate science students,
With three institutions involved, it is important to provide the means for frequent communication between their staff, if there is to be a genuine collaboration. Accordingly, there are three subject-based committees which bring together participating academics approximately twice a term, in order to generate and monitor the CAL packages which are in use or under development. Packages are usually developed by either one or two people from one institution in close collaoboration with colleagues from the other two. This continual involvement of other institutions in the development of a package is seen as being one of the most useful features of the project. Packages are inevitably less institution-dependent and therefore stand a better chance of transfer to institutions outside the project, which has already happened in two cases. Committees responsible for hardware/software, educational policy and transfer and dissemination of materials, were set up to co-ordinate the work of the project in these areas. They have enabled us to deploy the project's resources effectively according to its needs
D~RIFrlON OF THE PROJECT One of the two major aims of the project is to enrich the teaching, and more especially, the learning of selected topics in science by means of on-line interactive graphical displays. The use of graphics terminals was seen as essential in a science-based project because in the physical sciences the use of pictures or diagrams is often the most natural way to communicate ideas. We rely entirely on the interactive capability to facilitate learning, by allowing the student to interrogate the cornputer, or manipulate parameters of the system to obtain the results wanted. This allowed us to use low-cost installations instead of highly sophisticated systems required by a programmed learning approach, The other major aim of the project is to achieve the dissemination of teaching materials and methods beyond the institutions involved in their development, and for this too it is important that we use standard low-cost installations. CUSC is organised as a collaboration between three institutions: University College London, Chelsea College London, and the University of Surrey, and covers the three broad subject areas of Physics, Chemistry, and Biology. Some fifty members of academic staff are active participants on the project, including four heads of department. The project employs six full-time development staff, of whom three have primarily computing responsibflities and three concentrate on educational development and evaluation,
at any one time. The hardware set-up has been similar at the three institutions, using a dedicated mini-computer and, initially, two graphics terminals, to expand to six at each site during this year. The shortage of equipment has restricted student use, but nevertheless we have been able to test some thirty packages, each with an average of about fifteen students.
Educational philosophy As far as CUSC is concerned, a CAL package cornprises a computer program and a written student guide, and is designed for either one or two students to use at a graphics terminal during a one-hour period. As the aim is to enrich learning, the topics covered are generally taught elsewhere in the course so that the students already have some understanding, but use the computer to increase their knowledge or develop their under-
fThis paper was presented at the Seventh Conference on Computers in the Undergraduate Curricula 14--16June 1976,held at the State University of New York at Binghamton.
standing further. Typically, a package simulates a physical system and allows the student to investigate it by changing parameters within the system, or by using the
241
242
D.M. LAURILLARD
program to explain a phenomenon, or achieve a certain result. The way CUSC has been set up has inevitably had an important influence on the way it has developed and the kind of material it produces. Most significant, perhaps, is the fact that early on, it established a hard core of enthusiasts and has been able to expand by drawing in new people who have been excited by what they have seen happening in the project. Apart from collaboration, no special demands or directives are imposed on the participating academics, so that people with widely differing educational ideas and interests have been attracted to work in CUSC. The project began cautiously in its teaching philosophy, adopting no particular theoretical stance, but rather relying on an empirical approach to the development of materials, with considerable emphasis on formative evaluation. The high level of communication between participants has given us ample opportunity to benefit from our mistakes, so that while we have found that the early caution was justified, the pooled experiences since then have allowed the project to explore several different approaches to the use of the graphics terminals (see section 4 of the Appendix). Thus CUSC started small, but with the ability to continue expanding as more people become interested, Its non-directiveness means that widely differing types of materials can be developed, but its collaborative style means that they should all be widely usable.
TUg V~VgLOl~rr OF ~ G PACKAGES An important factor in the effective design of educational packages is the development procedure used, and CUSC has taken care to establish an efficient and workable procedure. This section outlines the rationale behind it, and describes how the procedure operates,
Questionnaire to staff and students Initially an open-ended questionnaire was sent to both staff and students likely to want to use CAL materials, with the aim of identifying students' academic needs in the different subject areas. Replies have been as general as "how to solve differential equations," or as specific as "how to interpret term symbols". Perhaps surprisingly, staff and students were in broad agreement as to the topics that present greatest learning difficulties. Results from the questionnaire have been helpful in the selection of topics for development as CAL packages, although not all student problems are best served in this way, and in some cases, alternative teaching methods have been found more appropriate,
Subject committee All three institutions are represented at each of the subject committees, and it is here that the decision to develop a CAL package on a particular topic is made. The decision is based partly on the information provided by the questionnaire, and partly on the members' experience of teaching those topics. The responsibility for initiating potentially useful packages therefore rests with these committees,
Initial draft of the package The initial design of a package plays a relatively minor part in its development overall, as the responsibility for its effectiveness is taken by the subsequent formative evaluation. It is helpful to begin with as good a design as possible, but since we expect several changes to take place during evaluation, we do not attempt to perfect it before student trials begin. However, a number of principles of good basic design have evolved, and these are reported in the next section.
Student trials When the first draft of a package is completed, student trials begin, and these are organised to allow changes to be made to the package between successive trials, each trial using three or four students. We use small numbers of students on each trial because we are attempting to design an effective package that is moulded to the needs and abilities of the students. The formative evaluation during these trials requires a number of detailed feedback measures that include ohservation schedules, feedback forms, interviews, and students' performance on the package. All these are best done with small numbers, and it would be unprofitable at this stage to attempt the kind of statistically valid description of student use that would necessitate large student numbers. During early trials, it is usual for an academic tutor to be present to assist students where needed and to supplement the deficiencies of the package. The ensuing interaction between students, computer and tutor is then recorded in detail (manually, for easier analysis, using the observation schedule) and this provides the main basis for future changes. The advantage of this procedure is that the human tutor is highly flexible and can respond to student difficulties by exploring, for example, a variety of explanations until he discovers those that the students find helpful. He can also provide hints and ask questions that lead the students to explore the subject matter more deeply for themselves. The trial session is therefore an approximation to the optimal learning situation for those students. By using a procedure that converges on a successful teaching situation, we can exploit that success by incorporating the teaching strategy used into the package, wherever this is possible. It is a highly labourintensive procedure, but that effort is an investment that reaps the reward of an effective and well-designed package. These results from observation are supplemented by interviews with students, and by analysis of their performance, obtained either from computer monitoring or from written work done during the session. Four or five such trials are usually sufficient to bring the package to a state where students can run it on their own, and further, usually minor, changes can be based on the continual monitoring done both by the computer, and by feedback forms administered to the students after each session. This reduced level of monitoring is maintained throughout the later stages of development of the package, both in the originating institution and in the institutions to which it has been transferred.
The design and development of CAL materials in undergraduate science EVALUATIONFINDINGS The experience gained in two years of the project has contributed towards a number of general findings related to the use of CAL in teaching science. The results outlined below constitute a distillation of this experience, and while they are not in any sense prescriptive, they have been very useful in forming a basis for further development and investigation of the issues that seem most important for the success of CAL, as interpreted in the CUSC project.
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For many teachers, therefore, CAL is now seen not as an expensive luxury, but as one solution for a number of quite disparate educational needs. SYMMETRY
OPERATORS
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The use o f C A L
The two most obvious advantages of the computer in v its use in teaching are (i) its capacity to handle data, and (ii) the interactive mode of communication. The first enables the computer to simulate a large number of physical situations; the second enables the student to interrogate this information source and generate required data, thus forcing the student to be an active participant rather than a passive recipient. We have found that the NEXT OPERATION ? !~1 need for CAL first becomes apparent when the teacher realises these features of the computer can be exploited Fig. l(b). in order to go beyond the normal resources of a university science department. For example, a package simulating a genetics experiment ("COEXIST--an exzP c: periment in population dynamics") allows the student to ErF Z = use the computer as though conducting an experiment 3 25 ..... that would, in reality, take years to complete. '-"--~. :: ::.../...-:...:::):i).:../:: : ?-:.:-..../.++++,...Teachers have discovered many similar ways in which ......::"+++++++ : : ....... : • .•.".++~#'##.###~####+ .....I the computer can help them extend their teaching into : .:():+T++~ ~ .... more interesting areas than before. But while this was o Nr.* ':'...::'.):~J~Wse~s-~ , . . . . . . . -..... often their reason for joining the project, having seen the ....... .........++##=sn~..++###s## I ........ ................... advantages of CAL for this purpose, many then pro . . . . . . . . : : .-..-++#####...'+++++++ I ,,:" ceeded to look for areas where it may improve upon ....... ..-...-++++..... ,, ... traditional teaching methods. One example is a package ~ : ::(.".:-. ...... ("GAUSSI"--Fig. la) that allows the student to practise the technique of analysis of Gaussian mathematical operations. Another example is a package ("PTSYMI"-.2 . P L E A S E PO:=JIT I,:,H ,::,_,R'.--:,:,~: Fig. lb) that generates any required symmetry operation Fig. l(c). and therefore gives the student greater scope for improving understanding than would be possible with a selection of models. ~ : ¢
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Fig. l. Examples of screen displays for packages. (a) Gaussian plots: the user enters parameters of the two Gaussians, at-
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tempting to make the envelope fit experimental data. (b) Point symmetry: the user selects an operation on the flag, and the resulting reflection or rotation is displayed. (c) Atomic orbitals: the user selects a cross-section of the orbital and the correspondingwave function is plotted. (d) Schroedingerequation for a particle in a one-dimensional square well: The user selects parameters for the wave function, which is then plotted.
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D.M. LAURILLARD
The heed for graphics It is imp,.rtant for CUSC to be able to justify its use of graphics t~ninals as, in the U.K. at least, their value has not yet been proved. They are seen to be particularly useful in mathematical modelling, as this is a notoriously difficult area for student understanding. It is a creative and dynamic process, requiring both imaginative thought and feedback in order to control the imagination. With most students it has been easier to stimulate and develop imaginative thought in connection with pictures and diagrams than with numbers and formulae. This calls, therefore, for graphics displays, If the computer is needed in teaching for its datahandling or interactive capabilities, it follows that graphics will be needed whenever the subject matter is best communicated by diagrams. This is such a common occurrence in science subjects that even those few of our packages which have used teletypes, have still generated the data in graphic form. From the experience of the last two years, therefore, we feel the use of graphics has been well justified,
Package design From the experience gained in the formative evaluation of more than thirty packages, a number of basic principles of design emerge. These do not themselves ensure successful packages, because success will depend also on such package-specific details as wording, terminology, types of diagrams used, etc., but they have acted as useful guidelines,, and as a way of passing on experience, Pre-package exercise. Students receive the written package guide before coming to the computer and are usually asked to complete some exercises linked to the computer topic. This is to encourage students to prepare '~ mselves for the theory contained in the package so they will be able to play a genuinely active role in operation of the program. The theory will not essarily be new to them, but we have frequently round that they need this preparatory exercise, even if only for revision. Introductory exercise. Most packages are designed for students to use unsupervised and in a self-directed style, This means that to get the most out of the package they need to know what options are available and how they may be operated. An introductory exercise consisting of a list of carefully written instructions that guides the students through the program acquaints them with all the Recognise and identify diagrams Rehearse difficult procedures Understand a mathematical model Visualise the subject Understand the behaviour of parameters Develop a problem solving strategy Perform a meaningful experiment details of the package and how it works. The remainder of this work on the package can then be genuinely
self-directed, once they are familiar with what is available. Suggested exercises. Although it is important to allow the students the freedom to work through a package in their own way, there should, nevertheless, be a stated goal for them to aim at. Without this, completely undirected work tends to result in inefficient use of the package for most students. In "Rutherford scattering" for example, students can generate particle trajectories by specifying values for the impact parameter and velocity. Without the suggestion that they look for cornbinations which give, say, small scattering angles, there was a tendency to simply "see what happens i f . . . " rather than to think about what should happen. Interaction with the computer. Students working within CUSC are, on the whole, naive computer users, and we therefore feel it is necessary to make the interaction with the computer as unobtrusive as possible. The precise details of design are, of course, very packagedependent, but after much experimenting a favoured form has emerged. Once the program is running, the computer asks simply NEXT? and the students may reply either with a number to select an option, or with a letter and number if they wish to change a parameter (see Fig. 1). This very simple form is all that is needed for a surprisingly high number of quite complex programs and has the great advantage of being very straightforward, even for the most naive computer user.
Student learning gains As described earlier, we have used an empirical approach to the development of packages using repeated student trials to mould the package into an effective teaching method that takes account of students' needs and abilities. We have found, therefore, that it is quite common for the aims of a package to adapt to those aspects of a topic that makes best use of the computer according to what the students need. For this reason we have not attempted any controlled test of the effectiveness of CAL in comparison with other learning methods, which rarely have the same aims. Learning gains have therefore been assessed with reference to the performance of students on exercises within the package, by their own reports, and by the tutor's reports of what the student has achieved. A summary of the improvements gathered in this way demonstrates the variety of capabilities of CAL. A package can help them to carry out the following (examples of actual packages in brackets): (Atomic orbitals, Fig. lc); (Genetic mapping); (Schr6dinger equation, Fig. ld); (Phasor diagrams); (Rutherford scattering); (A free-fall problem); (Population dynamics). To take two of these and look at them in some detail will give some indication of how the project works.
The design and development of CAL materials in undergraduate science
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A package that illustrated the concept of moment of inertia began as a more advanced package that used moments of inertia to study the idea of a centre of percussion. It became apparent in the early stages of evaluation that the students needed help with their understanding of the concept of moment of inertia before they could go on to apply it. The original package was quickly replaced by the required package and it has developed from there into one of the most successful packages produced. It is interesting to note that this incident occurred in the early stages of the project before we had circulated the questionnaire and was an example of how staff and student views can differ on what is needed, Several packages have been developed to simulate a practical experiment (e.g. population dynamics), often one that is too difficult or too expensive to do in the laboratory. Student comments on this type of package have strongly emphasised two major advantages: firstly, it cuts out tedious manual operations and allows them to concentrate on theory, and secondly, it always works! The success of these packages has led to the possibility of some future packages being designed to replace existing laboratory experiments. This idea has met with strong resistance from teachers who feel that students should be able to practise experimental skills, But some laboratory experiments have, as one of their aims, the greater understanding of related theory, and it
teachers preferred to write their own accompanying guide. As it is essential that the experience gained during development of the guide should not be lost, we now attempt to transfer the ability to rewrite student guides effectively. This is done by including in the documentation copies of all student guides that have been developed, and thoroughly tested, together with a teacher's guide which outlines the rationale behind them, and the possible uses of the computer program, which will generally remain unchanged. There is little emphasis within CUSC on producing a final polished product for transfer to other institutions. The aim is to transfer experience and ideas with the hope that this will be built upon and extended by the receiving institutions.
is here where, as the students point out, the computer does better. CAL is likely, therefore, to provide an alternative to at least some aspects of laboratory work. The student learning gains described in this section have been predominantly of higher order and these are more difficult to test than gains in, for example, factual knowledge. We have used pre- and post-tests on some packages, but these can assess only a small part of their educational value. We shall therefore continue to rely on staff and student reports, and student performance on exercises to assess learning gains.
Acknowledgements--The author wishes to thank all the academic
TRANSFEROF PACKAGES One of the most tangible successes of the project so far has been the level of transfer achieved. More than half the developed packages have been used in at least two of the participating institutions, and two have already transferred outside the project. The most important factor contributing to this success is the collaboration between institutions in the early stages of design of a package, because it is there that local idiosyncrasies are avoided. Collaboration also means that there is pressure on the designer to keep the package as widely adaptable as possible, and as a result, many of the transferred packages have been used for a variety of different teaching purposes. Good documentation is an important part of the transfer process and this, like everything else, has been subjected to experimentation to achieve the appropriate format. We originally thought that after extensive development, both the computer programme and student guide should remain unchanged after transfer. However, we discovered that the student guides rarely transferred:
CAG VoL 2, No 4--D
CONCLUSION The work described here is continuing and this paper should be seen as an interim report. We still have a long way to go, but already the evidence is persuasive: experience has shown us that interactive graphics are technically and economically feasible in undergraduate teaching, and the educational value of our use of CAL is becoming increasingly demonstrable as more and more academics find it is a worthwhile investment of their time and effort. Response from both staff and students suggests that CAL has a healthy future.
staff,developmentofficers, and students, who have taken part in CUSC,for their help and hard work, and to the National DevelopmentProgramme for encouragement and support.
APPENDIX 1
Pl0 Momentsof Inertia .StudentsNote* 1. ~ODUCT1ON This computer package is designed to give you a better understanding of the factors that affect the moment of inertia of a lamina of uniform density; both theoreticallyand intuitively.The program allows you to specify (draw) the shape of a lamina on the screen, by using the READ CURSOR key. Using the various optionsyou can verify to your own satisfaction the results you obtainedin the ore-package experiment. 2. Pre-requisite Beforerunning the program you must have studied unit 9 in the Particle Mechanics course. You must also have completed the exercise above to your own satisfaction. 3. Theoretical background The expression for the moment of inertia of a rigid body is /.
I = ~ r 2 dm J
where r is the distance from the axis of the mass element din. The 3. axis theorem for a lamina is I, = Ix + I,,
wherex, y, and z are mutually .1. axes through one point in the lamina,and the z axis is 3_ to the lamina.
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D . M . LAURILLARD
(2) The program assumes mass/unit area = 1. (3) If you accidentally press the reset key while using the cursor you will lose the cross hairs. To regain them, (a) press line switch (light goes out), (b) hold CTRL key down and press/key, (c) press line switch 0ight on).
The ]J axis theorem for any body is Io = f~ + Md~
where do. is .L distance between the chosen axis and a Jt axis through the centre of mass, L is the moment of inertia about the centre of mass,
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Notes on options: *For options 1, 2 and 3 you must use the read cursor key and the cursor to tell the program the point that you wish to specify as fixing the axis. *Option 4 needs two points to specify a straight line. In all cases the point or line which represents the axis will be labelled from 1 upwards, as will their moments of inertia. For example to draw a triangle:
=._.....• ~ • :~ Io
4.3 Options: OPTION? I gives the moment of inertia about an axis parallel to the x axis.* 2 gives the moment of inertia about an axis parallel to the y axis,* 3 gives the moment of inertia about an axis perpendicular to the plane of the screen 4 gives the moment of inertia about an axis lying in the plane of the screen at any angle.* 5 clears the screen and redraws the figure last specified. 0 clears the screen ready for another figure.
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To produce the first point position the cursor Ot this point and press the Read Cursor ( R C ) k e y . A small dash will mark the f i r s t corner t h a t you choose.
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4. The program 4.1 Log-on and run the program, Log-on at a graphics terminal and run the program"MOFI" (notes on how to do this are on the wall in the CUSC laboratory 4AY21). 4.2 Draw a lamina. This is very easy once you get the knack, The box on the screen represents an area 100 units x 100 units, This is the area inside which you draw the lamina. The corners of the lamina are specified in turn by moving the cursor (the feint crossed lines) to the relevant point, going round the circumference of the lamina, and pressing the read cursor key. When you have specified the last point, press the HOME key followed by the READ CURSOR key. Notes: (1) There are sometimes points on the screen that cannot be read by the R. C. key. If you choose one of these points by accident, the message PLEASE RE-POSITION THE CURSOR will be printed on the screen; re-position the cursor in a slightly different place and continue. Sometimes this causes an INPUT ERROR and will stop the program. To reprint your figure, type RUN3 and press RETURN.
YOU now have t o s p e c i f y the ~ast p o i n t on the triangle Move t h e c u r s o r to t h e p o s i t i o n of t h e t h i r d corner. Press t h e R.C. key.
The line joining the previously specified point to this new one will be drown
you now only hove to press the HOME key to,owed by the R.C. key, and the p r o o r a m wi, complete the triangle for you zt w,, then ask you for your opt,on
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5. Suggested exercises 5.1 Draw the lamina used in the practical. Use the program to check your answers to the questions in this pre-test. 5.2 Draw a square or rectangle. Check: (1) t h e / ~ axis theorem; (2) the .L axis theorem; (3) the expression derived analytically for its moment of inertin (see section on Theoretical Background), 5.3 Draw a figure. Find the two mutually perpendicular axes for which the moments of inertia is a minimum. Is this what you would expect?
The design and development of CAL materials in undergraduate science 5.4 Plot the momental ellipse. (This is extra to your course syllabus.) Find the moment of inertia of a rectangle about several axes (approx 10) in the plane of the lamina passing through the centre of mass (see diagram). Mark a length along them proportional to one over the square root of the moment of inertia. These points should lie on an ellipse--called the momental ellipse.
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