Bringing student centred experiences to the electronics laboratory: does this enhance student learning?

Transcription

1 Mini-Project Case Study Bringing student centred experiences to the electronics laboratory: does this enhance student learning? Dr Sherri Johnstone Dr Andrew Gallant, Dr Stuart Feeney, and Dr Dagou Zeze School of Engineering and Computing Sciences, Durham University, England Abstract The project focussed on three Level 1 laboratory experiments in which the students used academic principles from their courses to design, build and test complete systems which fit into their normal everyday experience. The three applications investigated were (i) an audio amplifier for mp3 players (ipods), (ii) filters used in music mixers and guitar pedals and (iii) a stopwatch. The hypothesis tested was: Does introducing new academic concepts via routes which are familiar in everyday life, encourage a more intrinsic orientation to learning? To test this concept, two experimental hardware platforms, known as the Durham University Analogue and Digital experimenters were designed and an appropriate syllabus developed to implement the teaching approach. Data on perceived outcomes were collected by student questionnaires and interviews. The paper questionnaire results suggest that introducing an experiential element into the laboratory teaching was not perceived by the students to enhance understanding or encourage them to pursue electronics further. The interviews however, revealed that together with other modes of learning, a greater variety of learning styles as described by Wolf and Kolb (1984) were accommodated, with some students showing a high level (more intrinsic) orientation to learning as described using Biggs SOLO taxonomy (1982). 1. Background The rationale behind this idea has stemmed from three routes. Firstly, feedback from current students, together with low numbers of students opting for Electronics in Level 3 indicated that although the academic principles delivered during laboratory sessions are at an appropriate level and aligned with lecture course material and assessments, the experiments are boring and lack relevance to the students. Secondly, problem-based practical projects have been successfully introduced to Science Experience events in local schools in the region (Johnstone, 2004). Thirdly, the laboratories in their current form do not expose students to the practical issues of interfacing electronic sub-circuits to produce larger systems. Thus, the academic team driving this initiative were aiming to exploit their previous experiences in project-based learning to induce a more intrinsic interest and thus a deep learning orientation. The resources in terms of hardware development and experimental design were supplied by Durham University. Thus, this mini-project was purely aimed at evaluating the effectiveness of this learning methodology. A Higher Education Academy Engineering Subject Centre Case Study 1

2 2. Methodology 2.1 Laboratory experiments The three original experiments were related to two lecture courses. The students were asked to read the laboratory script before the session. Then they were asked to spend three hours following the instructions from the script using the Durham Experimenter Systems and keeping a record of their findings in their hand-written laboratory books. These were discussed and marked with demonstrators the following week. The experiential experiments were designed to include a practical application to which students are accustomed but which does not necessarily relate to lecture materials. The approach proposed was designed to bridge this gap. (i) (ii) (iii) In the Operational Amplifiers and Circuits experiment, music from an mp3 player was passed through both an inverting and non-inverting amplifier configuration for both the left and right channels, such that the students could hear the effect of amplification, input impedance, distortion due to saturation and phase shift. The aim was to relate the experience of volume control on sound systems to basic electronic circuit principles. In the Resistor Capacitor (RC) circuit experiment, music from an mp3 player was passed through a low pass filter on the right channel and a high pass filter on the left channel. This could be related to woofer and tweeter type speakers or electric guitar pedals and was aimed to relate the circuit principle of low pass, high pass and bandpass filters to music and sound systems. The Digital Logic Gates experiment was based on a stopwatch. Although the students had not learnt all the concepts to completely design this, the aim was to show how the base principles of logic decoders could be used to convert binary outputs into base ten digit displays. The students were first asked to read the laboratory scripts before attending the laboratory session. The demonstrators would then show them the application and explain its operation, i.e. the audio amplifiers, filters and stopwatch. The students would subsequently carry out the base principle experiments as before. Finally, they were expected to apply their knowledge to recreate the applications. Records of their work were kept for discussion and marking in the following week with demonstrators. 2.2 Level 1 paper questionnaires In May 2009, six questions (Table 1) were given to a sample of 48 and to a second sample of 85 later in November There were five categories of response ranging from definitely agree to definitely disagree. A t-test on this data showed that there was no significant difference in the responses from the two cohorts. Also, for all of the questions, the mode did not change from the mostly agree response. For comparison, both data sets were normalised to a sample size of 100 for percentage comparison. Table 1. uestions used in the survey The electronics lab experiments have enhanced my understanding of the lecture material. I am happy with the content of the electronics laboratory experiments. The laboratory experiments give me an insight into how electronic products are designed and operate. I can clearly see the relevance of each laboratory experiment. The laboratory scripts are easy to follow. The laboratory experiments have encouraged me to pursue electronics further. A Higher Education Academy Engineering Subject Centre Case Study 2

3 2.3 Level 2 paper questionnaires Six questions were given to a sample of 65 in May 2009 and a sample of 82 in November Again, a t-test on this data showed that there was no significant difference in the responses from the two cohorts. The mode was in the Mostly agree category for both cohorts for all questions except question two where there was an increase from the Neither agree nor disagree category to the Mostly agree. Likewise for question six, the mode increased from Definitely disagree to the Neither agree nor disagree category from cohort 1 to 2. This suggests that there could be other factors in the electronics stream biasing the outcome of this study. For comparison both data sets were normalised to a sample size of 100 for percentage comparison. This was classed as the control group because no changes were made to the Level 2 laboratory. 2.4 Paper questionnaire conclusions The evidence from these data suggests that introducing an experiential element into the laboratory experiments was not perceived by the students to enhance understanding or encourage them to pursue electronics further. Two possible explanations are (i) the introduction of a concrete experience (experiential) stage did not assist students whose learning tended towards divergent and accommodative or (ii) the number of students exhibiting divergent and accommodative learning tendencies within these cohorts was small, such that introducing the concrete experience stage had minimal effect. 2.5 Level 1 interviews The paper questionnaires were designed to examine the perceived outcomes by the students and to explore further whether more learning orientations were accommodated. This next study, using interviews, focuses more on the detail of what the students actually did, how they carried out the learning process and the detail of what they actually learnt. From this evidence, the effect of the experimental design, expressed in terms of Kolb components from which learning orientations can be extracted, is explored. Based on the Kolb components, different learning orientations and levels of understanding have been suggested. Current results suggest that the experiments with the experiential aspects together with traditional lecturing and background reading methods enable students with a wide range of learning orientations to access the original academic principles (Johnstone et al., in press). This is consistent with Kolb s learning cycle. 3. Issues The paper questionnaires were given to cohort 1 in the Easter term after they had completed the lecture courses associated with the experiments and had started the revision process for their examinations. Cohort 2 was questioned towards the end of the Michaelmas term, a third of the way through the lecture material. Thus, a significant proportion of cohort 2 were meeting the basic concepts for the first time through the experiments. They were still adjusting to the methods of learning in higher education and still progressing through the cognitive levels of learning outcomes as described by Biggs (1982). The Level 2 control cohorts would experience the same effect when they met the new material but without the adjustment to higher education factor. Despite this, there were improvements in the modes suggesting other factors within the course were affecting their perceived outcomes. It is suggested that these surveys are repeated in May 2011 and November 2011 to further examine these factors. A Higher Education Academy Engineering Subject Centre Case Study 3

4 4. Benefits The interviews revealed that the students could now see a coherency in the academic principles due to the link given by the application. The application was always demonstrated before the students started their investigations. The slower students conveyed a feeling of disappointment at not at being able to complete the application. The course portfolio is now more balanced in accommodating different learning styles. This is an important step in encouraging higher level engagement with academic principles. 5. Evidence of Success A bid to apply this learning methodology to Level 2 laboratories has been approved by the School s Education Committee. The written laboratory reports this year show a greater depth of understanding, although this has not been rigorously evaluated. 6. How Can Other Academics Reproduce This? Durham University have produced two Experimenter boards as shown in Figures 1 and 2. These will be demonstrated at the Three Rivers Learning and Teaching Conference, Northumbria University on 12 th April 2011 (Johnstone et al, in press). Instructions on how to use the equipment together with a demonstration of the three applications will be available. Figure 1.Durham University Analogue Experimenter A Higher Education Academy Engineering Subject Centre Case Study 4

5 1 KEYPAD 2 3 F K0 K E D K2 K3 NOT AND NAND NOT OR NOR XOR DIGITAL LOGIC EXPERIMENTER A 0 B C STB MSD LSD BINARY CODED SWITCH A0 A1 S0 S1 J J J PE N_CARRY IN 0 1 A2 S2 RE 2 B3 B2 B1 B0 A3 CARRY IN S3 K K K UP/DOWN CLK 3 BINARY CODED DECIMAL DISPLAY S5 S4 S3 S2 S1 S0 B0 J-K Flip-Flop J-K Flip-Flop J-K Flip-Flop P0 Y3 Y2 Y1 Y0 X3 X2 X1 X0 B1 DECADE COUNTER P1 B2 N_CLK 0 0 P2 B3 CARRY OUT P3 N_CARRY OUT STATIC SWITCHES S5N S4N S3N S2N S1N S0N PULSE PULSE P0 P1 P0N P1N C 4-BIT ADDER D Flip-Flop D D D Flip-Flop SHIFT REGISTER DSA DSB N_CLK DECADE COUNTER N_CLK 0 0 N_CLK 1 1 UP/DOWN COUNTER UP/DOWN COUNTER PE 0 N_CARRY IN 1 RE 2 UP/DOWN 3 CLK P0 P1 L7 L6 L5 L4 L3 L2 L1 L0 LED STATE MONITORS LOGIC HIGH LOGIC PULL-UP / DOWN CLOCK GENERATOR CN CLK N_RST 2 3 P2 P3 N_CARRY OUT LOGIC LOW Figure 2. Durham University Digital Experimenter 7. Reflections It took longer than expected to produce the Experimenters. Thus, in hindsight we should have completed that phase first before attempting the pedagogical assessment. 8. References Biggs, J. and Collis, K.F. (1982) Evaluating the uality of Learning: The SOLO Taxonomy. London: Academic Press. Johnstone, S. (2004) A project to produce an analogue robot kit for Key Stage 3 students: Do customer-based projects affect student motivation? International Journal for Engineering Education 20(5) Johnstone, S., Gallant, A.J., Feeney, S.M. and Zeze, D.A. (In press) Bringing Student Centered Experiences to the Electronics Laboratory: Does this Enhance the Prehension Phase in Kolb s Experiential Learning Model? (submitted to Three Rivers Learning and Teaching Conference, Northumbria University, 12 th April 2011). Wolf, D.M. and Kolb, D.A. (1984) Career Development, Personal Growth and Experiential Learning, Organisational Psychology: Readings on Human Behaviour, 4 th ed, NJ, Prentice-Hall. A Higher Education Academy Engineering Subject Centre Case Study 5

6 Background Information Discipline Electronic Engineering Participants students, 3 postgraduate demonstrators, 3 lecturers Level 1 Pedagogical Approach Undergraduate laboratories Teaching Methods Practical experimentation Materials Required Hand-outs, Experimenter boards, USB connected software oscilloscopes Assessment used Laboratory note book, oral discussion with demonstrator, written laboratory report Contact Details Author(s): Dr Sherri Johnstone, Dr Andrew Gallant, Dr Stuart Feeney, Dr Dagou Zeze, School of Engineering and Computing Sciences, Durham University, South Road Durham, DH1 3LE, , sherri.johnstone@durham.ac.uk. March 2011 A Higher Education Academy Engineering Subject Centre Case Study 6