Paper presented at First European Conference on Physics Teaching in Engineering Education (PTEE97) Engineering College of Copenhagen (IKT), Copenhagen, Denmark, 4–6 June 1997.
Experientially based Physics Instruction using hands on Experiments and Computers. Jonte Bernhard School of Engineering, Högskolan Dalarna, S-781 88 Borlänge, Sweden,
[email protected]. Abstract The undergraduate physics laboratory at Högskolan Dalarna is equipped with computers at every lab-station (mostly PowerMac 7600) connected to a PASCO ScienceWorkshop interface. This type of "Microcomputer Based Laboratory" makes it possible to collect physical data in real-time and the data is immediately available for analysis and presentation. The almost instant feedback makes its feasible to introduce a new type of student experiments there the students passes through a "learning-cycle" in which the student co-operatively in a lab-team put forward a hypothesis and makes predictions of the outcome of an experiment, does the experiment and immediately receives feedback and the possibility to compare prediction and outcome. This learning-cycle strengthen learning and comprehension.
1. Introduction For some decades sensors attached to a computer have been used in most experimental physics research laboratories. An attachment of a sensor to a computer creates a very powerful system for collection, analysis and display of experimental data. When I was a doctoral student at Uppsala University and Risø National Laboratory in the 1980’s I spent several hours writing computer code to control data acquisition and to control the display of experimental results. Many times code was written from scratch or nearly scratch for every new experiment. With the introduction of microcomputers came a new generation of software for measurement and control and for example in 1986 did National Instruments release LabVIEW for Macintosh. The concept of virtual instrument and graphical programming was introduced. I included this historical introduction because its easy to forget the rapid development we have seen the last years. Not to many years ago it was difficult to set up a computerised experiment and special programming skills were needed. Many teachers thus perceive using computers in a school or university undergraduate laboratory to control experiment as to difficult based on their own experience just a few years ago. Today easy to use equipment and software are readily available, as would be described below, for both Macintosh and MS-DOS/Windows microcomputer systems. As will be discussed below this offers new opportunities for education.
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2. Microcomputer Based Laboratory Three years ago my university decided to invest in a new undergraduate physics laboratory at the Borlänge campus. To investigate the feasibility of a Microcomputer Based Laboratory (MBL) we purchased two ScienceWorkshop 7001 interfaces and some sensors from Pasco® scientific2 . Since investigation was satisfactory we have today two rooms in our undergraduate laboratory equipped with a total of 16 ScienceWorkshop 700 interfaces and many different sensors. One laboratory room is equipped with older Macintosh IIci computers (68030-processor)3 and the other with Power Macintosh 7600/8500. A typical MBL-systems consists of a sensor or a probe connected to a microcomputer via an electronic device known as an interface. The ScienceWorkshop™ 700 interface (SW 700) which we uses connects via SCSI to a Macintosh or to a Windows based PC-compatible computer4 . The use of the high-speed SCSI connection allows it to be used simultaneously for both data collection (up to 100 kHz sampling rate) and experimental control. SW 700 have four ports for digital input/output and three for analog input/output. The analog channels uses a 12-bit ADC and DAC and the analog input have to be in the ±10 volt range. The analog input is differential on all channels and two channels provides the possibility of 10 or 100 gain. With suitable sensors and accessories a computer equipped with a MBL-system such as SW 700 can for example become: a digital voltmeter, a triple-trace digital storage oscilloscope with differential inputs, a timer, a digital frequency counter, a spectrum analyser, a radiation monitor, a DC power source and a function generator. The associated ScienceWorkshop software is easy to use and allows the experimental data to be displayed as: digital meters, analog meters, oscilloscope, spectrum analyser using a FFT-routine, graphs and tables. The ScienceWorkshop software provides the possibility for further data analysis such as curve fitting, derivation, integration, histograms and user defined functions. Raw data, displays and analysed data can be printed or exported to a word processor for report writing or a to spread sheet for further analysis. A MBL-system can be used to do traditional recipe labs but the educational advantage of a MBL-system is the possibility to collect physical data in real-time and that the data is immediately available for analysis and presentation. The almost instant feedback makes its feasible to introduce a new type of student experiments there the students passes through a "experiential learning-cycle" as would be discussed below.
1
At that time sold as Signal Interface II Pasco® scientific, 10101 Foothills Boulevard, P O Box 619011, Roseville, Ca 95678-9011, USA. Web: http://www.pasco.com. E-mail:
[email protected]. National representatives of PASCO can be reached through the USA office. 3 For departments on a restricted budget it can bee noted that the older Mac IIci computers we still are using works satisfactory as a MBL-tool and the lower processing speed have only caused limited trouble. Older PCmachines can probably also be used for MBL. Much more frustration lies in having to use the newest versions of software like Microsoft Word or Excel on older computers. 4 For connection to a PC a SCSI-interface is necessary. A SCSI-interface is standard on Macintosh. 2
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Force sensor Physical object (Cart on an inclined plane connected by a spring to a force sensor)
Computer
Motion sensor Interface Fig 1. A typical MBL-set-up consisting of physical object, one or more sensors connected to an interface, an interface connected to a computer and a computer equipped with suitable software.
Fig 2. Results from the experiment in figure 1 displayed as graphs. The force and distance versus time plots and the phase space plot can be simultaneously shown. If the system is complemented with a suitable display device (LCD, computer projector or a TV with a suitable interface) the results on the computer screen can be shown to a larger audience like a lecture class.
3. Conceptual understanding in physics Some years ago I started to include some ”simple” conceptual questions in the exams of the physics courses I taught. These questions could be answered by qualitative reasoning and no calculations was needed. I was first quite surprised of the results: Most students performed very poorly on the conceptual questions which I considered to be almost to ”easy”, while they sometimes solved ”difficult” multiple-step quantitative problems better than I expected. Some of the ”top” students with high scores on the quantitative problems had very low scores on the conceptual part. What was brought to my personal attention was the result of Physics education that most students, even at the university level, do not learn basic concept as a result of standard instruction and often graduates with unaltered misconceptions and may have deep misunderstandings [See, for example : Trowbridge and McDermott (1980), Johansson (1981), Trowbridge and McDermott (1981), McCloskey (1983), Driver (1983), Halloun et al (1985a), Hal-
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loun et al (1985b), Hestenes et al (1992), McDermott and Shaffer (1992), Wilson (1997), McDermott (1997) and Arons (1997)]. Cognitive studies [See, for example Redish (1994)] have proposed that people tend to organise their experiences and observations into mental models. The students comes to us with approximately 20 years of real-world experience and this experience have formed strong mental models called preconceptions (ideas held before instruction). These preconceptions may be incomplete and contain contradictory elements and also be misconceptions. This means that our students are not blank slates to be filled with teacher wisdom and that misconceptions in the mental models of students must be effectively addressed in a physics course. Unfortunately cognitive studies and physics education research have shown that it is very difficult to change an established model substantially. To change an established mental model into a new one the new model must be 1. understandable, 2. plausible, 3. be in strong conflict with predictions based on the existing one and 4. the new model must be seen as useful [Posner et al. (1982)]. At a meeting at Tufts University, USA, in 1992 the participating physics education researchers reached an agreement on the following points [See McDermot (1997) or Thornton (1997)] • Facility in solving standard quantitative problems is not adequate criterion for functional understanding. Questions that require qualitative reasoning and verbal explanation are essential. • A coherent conceptual framework is not typically an outcome of traditional instruction. Rote use of formulas is common. Students need to participate in the process of constructing qualitative models that can help them understand relationships and differences among concepts. • Certain conceptual difficulties are not overcome by traditional instruction. Persistent conceptual difficulties must be explicity addressed by multiple challenges in different context. • Growth in reasoning ability does not usually result from traditional instruction. Scientific reasoning skills must be expressly cultivated. • Connections among concepts, formal representations, and the real world are often lacking after traditional instruction. Students need repeated practice in interpreting physics formalism and relating it to the real world. • Teaching by telling is an ineffective mode of instruction for most students. Students must be intellectually active to develop a functional understanding” 4. Experiential learning in physics Over past few years a number of active engagement curricula based on the constructivist model of student thinking and learning have been developed. A review of some of these curricula can be found in Van Heuvelen 1991, Redish (1996) and in Wilson (1997). The common denominator of these curricula is that they encourage active learning and peer co-operation and that they addresses student misconception in a constructivist mode. Inspired by the potential which was seen in the MBL-tools and by the discovery based laboratory curricula RealTime Physics, Tools for Scientific Thinking (Sokoloff et al 1994, Thornton and Sokoloff 1990, 1992, 1993 and 1996) and Workshop Physics (Laws 1989, 1991
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and 1997) a process to reform undergraduate physics teaching was started some years ago at Högskolan Dalarna. We firmly believe in the importance of giving the students real-world experience as an introduction to concepts and formal representations. Emphasis is thus put on experiential learning. Experiential learning, which has its origin in the works of Dewey, Lewin and Piaget, focuses on the central role that experience plays in the learning process. ”Learning is the process whereby knowledge is created through the transformation of experience” [Kolb 1984] and ”learning from experience is the process whereby human development occurs” [Vygotsky cited in Kolb (1984)]. Experience is essential to learning, but one also have to do something with it to construct knowledge as displayed in the experiential learning model by Kolb displayed in figure 3. In physics courses I have tried to follow a model there a new concept always is introduced in lecture by a demonstration. Demonstrations are selected by their importance for conceptual introduction and development and not for their ”entertainment” value. Some demonstrations uses MBL-tools [Bernhard 1997b]. Thus direct experience of a concept is given before the presentation of theory in lecturers (concepts first). References justifying this approach is given in Bernhard (1997b). Fig 3. Experiential learning model The theory are later applied in solving problems in recitation sessions. These have hitherto been quite traditional, but emphasis have been put on ”thinking aloud” about the concepts applied and to discuss the context of a problem and the relevance of the answer. In future application of some more active engagement methods in recitation sections will be considered. In the course laboratory the students again gain realworld experience. Most laborations are of a discovery type and the students are usually asked to start an experiment by discussing with their peers and make a prediction of the outcome of an experiment. Thus the students are required to examine their preconceptions relevant to the phenomenon being studied. Secondly they perform the experiment and are asked to compare outcome and prediction. If the outcome and prediction do not agree they are asked to reflect on their observations. This causes a conceptual conflict which (hopefully) forces the students to overcome misconceptions (Hewson and Hewson 1984). The students are asked to write a report after each laboratory session. This services several processes: While describing a phenomenon in their own words, the students once more have to reflect on their own conceptions, and writing reports is also a good training for life after graduation. It has been shown that better conceptual understanding the problem solving ability of students are also improved (Hestenes and Wells 1992).
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5. Conclusion and discussion Our reformed curricula with emphasize on experiential learning with ample use of real-world connections and with use of active engagement labs using MBL-tools have been well received by most students. Our introductory mechanics (new curricula; 7,5 ECTS credits) class 1996/97 academic year have been tested for conceptual understanding with the Force Concept Inventory (Hestenes et al 1992, Bernhard 1997a) and they performed slightly better than students who had taken both introductory and advanced mechanics courses (old curricula; 15 ECTS credits). This result is encouraging and indicates that our curriculum reform is a move in the right direction. Our result is supported by Hake (1997a and 1997b) who have collected Force Concept Inventory (FCI) data from many different physics classes and who have found a significant difference in gains between active-engagement curricula and ”traditional” teaching methods. Since our reform of our physics teaching have just started we have had implementation and technical problems due to lack of experience with new equipment and teaching methods. With further development of our curricula and gained experience we should be able to make full use of the educational advantages of new methods and our MBL-equipment and we will se further improvements in a near future. References Arons A 1997 Teaching Introductory Physics (Wiley, New York). Arons book contains an extensive bibliography. Bernhard J 1997a Swedish translation of Force Concept Inventory (Hestenes et al 1992), Högskolan Dalarna, Borlänge, Sweden. Bernhard J 1997b ”Interactive lecture demonstrations using MBL-equipment” Paper presented at First European Conference on Physics Teaching in Engineering Education (PTEE97) Engineering College of Copenhagen (IKT), Copenhagen, Denmark, 4–6 June 1997. Driver R 1983 The Pupil as Scientist (Open University Press, Milton Keyenes) Hake R R 1997a ”Interactive-engagement methods in introductory mechanics courses”, to be published Hake R R 1997b ”Interactive-engagement vs traditional methods: A six-thousand-student survey of mechanics test data for introductory physics courses”, to be published Halloun C, Ibrahim A and Hestenes D 1985a ”The initial knowledge state of college physics students”, Am J Physics 53 1043–1055 Halloun C, Ibrahim A and Hestenes D 1985b ”Common sense concepts about motion”, Am J Physics 53 1056–1065 Hestenes D and Wells M 1992 ”A Mechanics Baseline Test” Phys Teach 30 159–165 Hestenes D, Wells M and Swackhamer G 1992 ”Force Concept Inventory” Phys Teach 30 159–165 Hewson P W and A’Beckett Hewson M G 1984 ”The role of conceptual conflict in conceptual change and the design of science instruction” Instructional Science 13 1–13 Johansson B 1981 Krafter vid rörelse. Teknologers uppfattningar om några grundläggande fenomen inom mekaniken (in Swedish). Dep of Education, Univ of Gothenburg, Gothenburg, Sweden. Karplus R 1977 ”Science Teaching and the Development of Reasoning” J Res Sci Teach 14 169-175 Kolb D 1984 Experiential Learning (Prentice Hall, Englewood Cliffs)
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Laws P W 1989 ”Workshop Physics – Replacing Lectures with Real Experience” Proc of the Conf on Computers in Physics Instruction (Addison-Wesley, Reading) Laws P W 1991 ”Calculus-based physics without lectures” Phys Today 44 24–31 Laws P W 1997 Workshop Physics, Activity Guide (Wiley, New York) McCloskey M 1983 ”Intuitive Physics”, Sci Am 248 122–130 McDermott L C and Shaffer P S 1992 ”Research as a guide for curriculum development: An example from introductory electricity. Part I: Investigation of student understanding”, Am J Physics 60 994–1003 and erratum, ibid 61 (1993) 81 McDermott L C 1997 ”How research can guide us in improving the introductory course” Proc Conf on Intro Physics Course, (Wiley, New York), pp 33–45. Posner G J, Strike K A, Hewson P W and Gertzog W A 1982 ”Accommodation of a scientific conception: toward a theory of conceptual change”, Science Education 66 211-227 Redish E F 1994 ”The Implication of Cognitive Studies for Teaching Physics”, Am J Physics 62 796-803. Also at http://www.physics.umd.edu/rgroups/ripe/papers/cogsci.html Redish E F 1996 ”New Models of Physics Instruction Based on Physics Education Research” to be published in Proceedings of the Deutschen Physikalischen Gesellschaft Jena Conference 1996. Also at http://www.physics.umd.edu/rgroups/ripe/papers/jena/jena.html Sokoloff D R, Thornton R K and Laws P W 1994 RealTime Physics: Mechanics (Vernier Software, Portland, Oregon, USA) Thornton R K 1997 ”Learning Physics Concepts in the Introductory Course: Microcomputerbased Labs and Interactive Lecture Demonstrations”, Proc Conf on Intro Physics Course, (Wiley, New York), pp 69–86. Thornton R K and Sokoloff D R 1990 ”Learning motion concepts using real-time, microcomputer-based laboratory tools”, Am J Phys 58 858–867 Thornton R K and Sokoloff D R 1992 Tools for Scientific Thinking – Motion and Force Curriculum and Teachers’ Guide, Second edition (Vernier Software, Portland, Oregon, USA) Thornton R K and Sokoloff D R 1993 Tools for Scientific Thinking – Heat and Temperature Curriculum and Teachers’ Guide (Vernier Software, Portland, Oregon, USA) Thornton R K and Sokoloff D R 1996 ”Assessing and Improving Student Learning of Newton’s Laws Part I: The Force and Motion Conceptual Evaluation and Active Learning Laboratory Curricula for the First and Second Laws” to be published Trowbridge D E and McDermott L C 1980 ”Investigation of student understanding of the concept of velocity in one dimension”, Am J Physics 48 1020–1028 Trowbridge D E and McDermott L C 1981 ”Investigation of student understanding of the concept of acceleration in one dimension”, Am J Physics 49 1020–1028 Van Heuvelen A 1991 ”Learning to think like a physicist: A review of research-based instructional strategies”, Am J Physics 59 891–897 Wilson J (ed) 1997 Proc Conf on Intro Physics Course, (Wiley, New York)
