This article was downloaded by:[alessandro@coltec.ufmg.br] On: 29 November 2007 Access Details: [subscription number 787572227] Publisher: Routledge Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK International Journal of Science Education Publication details, including instructions for authors and subscription information: http://www.informaworld.com/smpp/title~content=t713737283 Students' Performance in Investigative Activity and Their Understanding of Activity Aims Alessandro Damásio Trani Gomes a; A. Tarciso Borges a; Rosária Justi a a Federal University of Minas Gerais, Brazil First Published on: 23 October 2007 To cite this Article: Gomes, Alessandro Damásio Trani, Borges, A. Tarciso and Justi, Rosária (2007) 'Students' Performance in Investigative Activity and Their Understanding of Activity Aims', International Journal of Science Education, 30:1, 109 - 135 To link to this article: DOI: 10.1080/09500690701697520 URL: http://dx.doi.org/10.1080/09500690701697520 PLEASE SCROLL DOWN FOR ARTICLE Full terms and conditions of use: http://www.informaworld.com/terms-and-conditions-of-access.pdf This article maybe used for research, teaching and private study purposes. Any substantial or systematic reproduction, re-distribution, re-selling, loan or sub-licensing, systematic supply or distribution in any form to anyone is expressly forbidden. The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material. Downloaded By: [alessandro@coltec.ufmg.br] At: 11:30 29 November 2007 International Journal of Science Education Vol. 30, No. 1, 15 January 2008, pp. 109–135 RESEARCH REPORT Students’ Performance in Investigative Activity and Their Understanding of Activity Aims Alessandro Damásio Trani Gomes*, A. Tarciso Borges and Rosária Justi Federal University of Minas Gerais, Brazil alessandro@coltec.ufmg.br 0Taylor 00 Mr. 000002007 AlessandroGomes & Francis International 10.1080/09500690701697520 TSED_A_269633.sgm 0950-0693 Original 2007 and Article (print)/1464-5289 Francis Journal of Science (online) Education This study investigates the relationship between the students’ understanding of the aims of an investigative activity and their performance when conducting it. One hundred and eighty-one year nine students from a public middle school in Brazil took part in the study. Students working in pairs were asked to investigate two problems using a computer-based environment. All their attempts to collect information were recorded in a log file, which registered the history of each duo investigation. After completing each investigation, all the participants were asked to explain in writing what the objective of the task was. Results obtained showed that a proportion of the students had some difficulties recalling the declared aims of the activities. However, those who succeeded in recognising the stated aims of the tasks showed a superior performance in conducting their investigations. This performance was graded according to both the proportion of adequate and consistent tests carried out and the quality of the investigation which was done. Introduction In many countries, recent years have been characterised by a remarkable interest in redefining the aims of secondary science curriculum, caused by both a general lack of satisfaction with the current state of science education as well as by the rapid spread of new technologies which has changed our everyday lives regarding many essential aspects (AAAS, 1990; Millar, 1996). These innovations introduced in science curricula have long been part of the debates about (i) the most important aims of the science curriculum in compulsory education; and (ii) the teachinglearning strategies that seem to be more suitable to prepare students for citizenship and to deal with the uncertainties of a world in a quick process of changing. In this *Corresponding author. Federal University of Minas Gerais, Faculty of Education, Belo Horizonte, Brazil. Email: alessandro@coltec.ufmg.br ISSN 0950-0693 (print)/ISSN 1464-5289 (online)/08/010109–27 © 2008 Taylor & Francis DOI: 10.1080/09500690701697520 Downloaded By: [alessandro@coltec.ufmg.br] At: 11:30 29 November 2007 110 A. D. Trani Gomes et al. context, from comprehensive educational and curricular concerns, the debate about school laboratories assumes a new importance. Practical work is not a distinctive aspect of secondary education in Brazilian schools, due to scarce resources and inadequate initial science teacher education. However, secondary and university teachers seem to believe that science teaching could be greatly improved if schools had well equipped laboratories contributing to raising students’ learning and interest toward science (Borges, 2002). As in many parts of the world, elementary and secondary education in Brazil experienced the recent movement towards curriculum reform. One of the dominant ideas in science education in this movement is that schools should give priority to scientific literacy for all students, instead of delivering traditional propaedeutic teacher-centred education aiming at preparing a minority of secondary students for further studies at university level. Educational researchers, scientific committees and associations have been advocating the teaching of science based on open problem solving and inquiry. The role of practical work in science teaching is a perennial issue in academic forums (Millar, 1991; Minstrel and van Zee, 2000), although most scientists and science educators endorse a view that practical work has the potential of making a difference in terms of students’ interests and views of science. However the matter of how effective practical work could be and what students should learn about in the laboratory is still an open discussion. In line with these arguments, we have been involved in disseminating the ideal of teaching science adopting problem-based activities and short investigation, so that students have opportunities to practice making decisions, elaborating and sharing their plans for conducting specific investigations and for learning from solving more open problems (Borges, 1997; 2002). We are quite aware that the productive use of investigative activities as tools for teaching and learning science depends mostly on students’ competence for developing reasoned plans to conduct their investigations and to understand what they are expected to achieve on completing them. That is needed so they can engage in practices of producing knowledge claims and assessing critically the findings of their colleagues. Then providing secondary students with opportunities to practice solving empirical ill-structured problems becomes a promising strategy for teaching and learning science. It has the potential to help students in the process of making their thinking about the world more scientific (Lijnse, 1995). We see investigative activities as tools for constructing arguments about questions of scientific interest and thus, school investigations should be concerned with the solving of ill-structured problems that have no beforehand known answer and seek to give opportunities to students to emulate the doings of professional scientists. These activities are posed with the main purpose of engaging students in developing a plan for the course of their work, and in looking for information and evidence they need to be able to put forward solutions for the problems they face (Borges, 1997, 2002). However, the use of investigative activities in science education as a teachinglearning strategy depends mainly on the students’ competence and skills when Downloaded By: [alessandro@coltec.ufmg.br] At: 11:30 29 November 2007 Students’ Performance in Investigative Activity and Their Understanding 111 planning and implementing the tasks to obtain conclusions (Germann & Aram, 1996). This involves developing some understanding of the role of theories and evidence in science (Koslowski, 1996; Kuhn, Amsel & O’Loughlin, 1988), and how scientific knowledge is produced and evaluated, which seems to be learned in lecture classes or by reading since it involves tacit components. In order for this to happen we think all science students should be given opportunities to engage in practices aiming at developing abilities and competences related to aspects of the scientific investigation process e.g. the design and testing of hypotheses, and the analysis of evidence. We believe that the starting point is developing an understanding of the role of measurements and errors in practical work (Lubben & Millar, 1996; Lubben et al., 2001), and understanding how to devise and conduct fair tests, i.e. adequate and consistent tests to produce unconfounded data. This involves conceptual and procedural aspects, as pointed by Chen and Klahr (1999), and is not just a matter of following a set of rules or being told about the ‘scientific method’. An adequate and consistent test is one that takes the set of variables describing a problem-situation and manipulates them in a way similar to that defined by Chen and Klahr (1999) as a control of variables strategy. The test is adequate if the variable whose effect one wishes to know will be taken as an independent one. The test is consistent if only this independent variable changes in two or more repetitions of the experimental trial, whilst all the other variables are kept unaltered. The definition of adequate and consistent testing, as outlined above, is appropriate for discussions of the match of students’ understandings to their performance in conducting practical tasks and the role of experiments in science education. Other forms of producing evidence are important and ordinary in many areas of science. If one masters this strategy for controlling variables, he/she should be able to plan experimental tests in which the focus variable (by which we mean the one whose effect one wishes to determine) is changed, while the others are kept constant. Moreover, one should be able to refuse inconsistent tests in which this situation has not occurred. It is only by using an efficient strategy of control and a systematic combination of the many variables involved in the solution of the practical problem that one can get reliable and uncontroversial data. Without this, the experiments do not produce data and evidence which will support the statements and conclusions for the problem being solved. This issue has been discussed in developmental psychology by researchers of the Piagetian school, and there are reasons to doubt that children’s scientific thinking develops as easily and naturally as it was previously believed (Fisher and Silvern, 1985). We are not concerned with the control of variables skill per se. Our concern is that this is not a subject taught explicitly at any point of elementary and secondary school in Brazil, and it seems to be essential if we want children to be able to understand how to deal with practical tasks and why they do it that way, i.e., if we want students to learn the role of experiments in science and how scientific knowledge is produced and validated. Besides dominating sound control of variables strategies, the student should understand what the task he/she has to solve is about; that is, the purpose of the Downloaded By: [alessandro@coltec.ufmg.br] At: 11:30 29 November 2007 112 A. D. Trani Gomes et al. investigative activity which he/she is conducting (Schauble, Klopfer and Raghaven, 1991). This study was designed to investigate whether there is any relationship between the recognition of the aims of investigative activities that are proposed to year 9 students and their competence to perform adequate and consistent experimental tests. The activities were proposed as open problems and developed in a computer simulation environment. The Relationship Between the Identification of the Aim and Experimentation Strategies The investigative activity is a complex task that calls for a combination of a chain of skills and processes. The main goal of this kind of activity is to produce knowledge through setting up hypotheses by means of experiments. According to Gott and Duggan (1995), the processes and skills related to investigative activities may be seen as results of the interaction of two different kinds of knowledge: conceptual and procedural. Conceptual knowledge consists of understanding the scientific ideas, which are based in facts, laws and principles relevant to the situation. Procedural knowledge refers to necessary knowledge to make science, that is, the procedures and strategies needed to obtain the solution of a problem. By recognising the importance of the interaction between conceptual and procedural knowledge, Klahr and Dunbar (1988) proposed an integrated model of the cognitive processes involved in the solving of practical problems. They identified two different but related areas: the hypothesis and the experimental spaces. According to these authors, in any process of discovery—no matter whether it is scientific or the solving of a daily problem—the first step is searching for a hypothesis. Regularly, the hypotheses consist of propositions stating any kind of causal relationships between the problem variables. Thus, that first hypothesis leads the process of discovery while it is not replaced by any other. The initial hypothesis is generally based on the solver’s previous knowledge about that specific domain. This hypothesis may be set up by means of exploratory experiments, if either the knowledge is not enough or there is lack of fundamental information. The hypotheses are evaluated, changed and even reformulated by means of experimentation. If the aim is to create information to formulate new hypotheses, then the experiments should be configured to generate reliable, interesting, and revealing information. If the aim of the experimental search is to test hypotheses, the tests realised should allow the researcher to distinguish between plausible hypotheses and their opponents. Klahr and Dunbar argued that the model they developed, named SDDS (Scientific Discovery as Dual Search), can be applied in any situation in which hypothesis formulation and data gathering occur. Their model characterises scientific research as a series of complex and cyclic processes based on hypothesis formulation, experimentation and the evaluation of evidence. Downloaded By: [alessandro@coltec.ufmg.br] At: 11:30 29 November 2007 Students’ Performance in Investigative Activity and Their Understanding 113 Studies that investigate the performance of individuals while conducting investigations (Schauble & Glaser, 1990; Schauble, 1996; Chen & Klahr, 1999; Gomes, 2005) agree that various factors influence the strategies adopted to complete a practical task. Some studies suggest that students’ understanding of the aims of the tasks may affect their choice of the strategy for controlling variables. Schauble, Klopfler and Raghavan (1991) encouraged 16 students from 5th and 6th grade to work in two different ways, which they defined as the ‘engineering model’ and ‘science model’ of investigation. Table 1 introduces the characteristics of each model. Two different activities were developed in order to carry out this research. These were named ‘canal task’ and ‘spring task’. For the canal activity a scale model of a navigation canal, in which the depth of the canal could be changed, was built. Boats were represented by geometric forms in which the mass, shape, and size could be varied. For the spring task, a spring was tied to a support. Bodies with different masses and volumes and a transparent container in which the bodies were suspended by the spring, but submerged in water, were used. Both tasks included about the same amount of possible variation, and both were designed to include a mix of some effects that were consistent with children’s prior beliefs and others that were inconsistent. In this way, prior beliefs and the evidence must both be considered in figuring out how the systems work. In order to encourage each group of children to adopt one way of working, the researchers used explanatory texts to persuade each child to work following only one model. Half of the children were randomly assigned to an engineering problem context and the other half to a science context. All the children worked with both activities. The canal task is not usual in school science classes, so the authors expected that students would try to describe the characteristics of a boat that would cross the canal in a higher speed. In this way, the structure of the activity was consistent with the Table 1. Goal Strategies Procedure Features of children’s engineering and science models of experimentation, according to Schauble, Klopfer & Raghavan (1991) Engineering Model Science Model Make a desired or interesting outcome occur or reoccur Understand relations among causes and effects Compare highly contrastive instances Establish the effect of each potentially important variable Emphasis on making exclusion, or non causal, inferences and inferences of indeterminacy Seeks to test of all combination, if feasible Inferences Emphasis on making inclusion, or causal, inferences Search Focuses on variables believed to cause the outcome When the desired outcome (or acceptable approximation) is achieved Stop rule When systematic test of each manipulable variable is completed Downloaded By: [alessandro@coltec.ufmg.br] At: 11:30 29 November 2007 114 A. D. Trani Gomes et al. aim of trying to produce an expected result (a faster boat). On the other hand, the spring task is a traditional school activity, and familiar to the children. This task does not include results that can be readily interpreted as more or less desirable. Therefore, it was expected that the investigation would be more careful, determining which variables would influence on the stretch of the spring. In spite of the differences between the activities, it could be perceived that when students were working with the science approach, they were more engaged in determining what factors were or were not influencial on each activity. In other words, children worked in a more systematic way, establishing the effect of each variable on the system. When students worked with the engineering approach, they preferred to choose contrastive combinations and concentrated themselves on factors they believed to be causal. At the same time, they ignored the factors thought of as non-causal, even in a mistaken way, in order to optimise the results. More often, students working in the engineering problem context used a trial and error strategy and students in the science problem context carried out a more careful and systematic inquiry. This result shows that the strategies of variable control used by the students are closely related to the ways they perceived the aim of the task. It also showed us that we should be concerned much more with having the students understanding not only the content, but also the aims of the activities they do. However, the difficulty in understanding the aims of the practical activities is not only an issue for students. Sá and Borges (2001) argued that there is a ‘decline’ in understanding the goals originally attributed to a determined activity by its authors. They concluded that both students and teachers, mainly the less experienced teachers, are not able to understand clearly the aims of the activities when they read the guidebook. Borges (1997, 2002) points out that only rarely do teachers develop systematic plans for the practical work they assign to students, followed by explanations and the discussion of their aims. Quite too often, teachers and students work with unclear and implicit pedagogic aims. Students can learn well and rapidly how to survive the lab tasks, by following the ritual of executing the instructions provided, preparing the equipment and measuring the quantities they are ask to obtain, and being able to represent the numbers they get in tables and graphs, even when they show poor understanding of why they did all those activities and measurements in those particular ways, and of what those numbers and graphs mean. Therefore, they fail to learn the ideas intended by the teacher or the curriculum designer from practical work activities. Hart et al. (2000) established differences between the purposes and the aims of a practical activity. According to them, the first are the pedagogic purposes established by the teacher, that is, the reason why such activity is being conducted, the way it is organised, and what educational results the activity may produce to the students’ learning process. The aim of the activity refers to the narrative presented to the students on the activity sheets, i.e., the aims are ordinarily specific content topics (for instance, to obtain the relationship between tension and current for a Downloaded By: [alessandro@coltec.ufmg.br] At: 11:30 29 November 2007 Students’ Performance in Investigative Activity and Their Understanding 115 conducting wire). This is a source of difficulties, according to the authors, because at most times students only recognise the immediate aims of the activity, and they neither create or establish connections between the activities done and the learning caused by them. As we have already seen, some studies (Hart et al., 2000; Sá & Borges, 1999, 2001) point out that students find it difficult to understand correctly the aims of the proposed activities, which can impede their performance and their potential to learn from them. In this sense, if we compare the so-called understood aims with those previously stated we can evaluate the degree of ‘fading’ of the understanding of task aims and try to become conscious of how the grasping of the aims of the activities influences both the performance and the strategies of students during their performance. Research questions This is one part of a broader research project in which we tried to develop a methodology which characterised the students’ thought along investigative tasks. We also sought to find the relationships among students’ understandings of the activities’ aims and of the concepts involved, and their performance when conducting them. The research questions that have guided this work are: (a) Do Brazilian middle school students think of adequate and consistent tests in planning and conducting practical investigations? (b) Is there any relationship between the way students understand the aim of a practical problem and their performance in planning and conducting an investigation to solve it? These are aspects which deserve investigation because the structure of the Brazilian system of compulsory education is distinct from the English-speaking and European world in many respects. The most important difference is that practical work is not usual in science education. In Brazil, primary education used to start at age of 7 and lasted for 11 years. The first eight years comprise the ‘fundamental school’, and the last three years form the ‘middle school’. As a result of educational reform of neoliberal inspiration during the 1990s, there are different systems of progression in school in many states. In middle school it is usual that to be promoted on to next year, students are required a minimum attainment, normally a mark of 60% of the points in each subject matter. Those who failed are kept, studying the same subjects again, in the following school year. Over time, increasing drop out and the phenomenon of school repetition has distorted the correspondence between age and schoolyear. In this way, it is common to find students one or two, and even more, years behind the school-year of children of the same age. Middle school is distinct from fundamental school mainly because it marks the first contact of students with teachers specialised in science disciplinary fields. Science is taught as separate subjects—physics, chemistry and biology—to all Downloaded By: [alessandro@coltec.ufmg.br] At: 11:30 29 November 2007 116 A. D. Trani Gomes et al. students. Science teachers from the initial years of Fundamental school normally have backgrounds in biology and related areas, while physics, chemistry and biology teachers are expected to have a university degree in their area, which entitles them to get a licence to teach these subjects. A recent change added another year to elementary school so that, from 2005, children start attending fundamental school at age 6. We will be referring the previous status quo because all the students who took part in this study had 11 years of basic education. Methodology We split the data collection into two different sessions, in which different instruments were used. In the first session, students simulated two investigations in a computer environment and all their choices were registered in log file. After doing the two activities, the aims the students attributed to the activities were probed. Only data relative to the second investigation are analysed in this work. Subjects 181 middle school students with ages from 14.9 to 18.3 years from a large urban area in the south-east of Brazil took part in the research. Their age distribution is shown in Figure 1. Participants were distributed into seven classes taught by four physics teachers. One of the authors of this work taught two classes, but had no direct participation in data gathering. The school is attached to a public university and has an experimental character, and this was one of the reasons for choosing to conduct the study there. Another reason was that all year 9 students in this school have regular physics and other science laboratory classes on alternate weeks. This is their first contact with practical work, as it is usually done in upper secondary education. In this way, the prior learning experiences of science practical work of the students participating in this study are not much different from more typical Brazilian schools. Figure 1. Histogram of students’ age distribution Instruments As mentioned above, the empirical material of the research was gathered using two investigations and one open question. In order to better organise this paper, these research instruments will be described separately, according to the sequence in which they were introduced to the students. Investigative Activities The two investigative activities were carried out using computer simulations. The preference for simulations instead of the didactic experiments ordinarily used was motivated by the need to allow students enough time to conclude their experiments Mean: StDev: N & Downloaded By: [alessandro@coltec.ufmg.br] At: 11:30 29 November 2007 Students’ Performance in Investigative Activity and Their Understanding 117 16.0 0.7 181 $ " # Figure 1. $ % & Histogram of students’ age distribution and to facilitate the collection of interesting data for the research. The use of a traditional hands-on activity would demand excessive time for students to set up the experiments, collect and analyse data, draw conclusions and write up their reports. Moreover, our interest neither depended on how students would collect the data nor on their correct readings of apparatus, data organisation and manipulation of the equipments. We only wanted to know: (i) whether students were able to spontaneously think of adequate and consistent tests when planning how to conduct and execute simple investigations; and (ii) what is the relationship, if any, between their understanding of the aims of the activities and such thoughts. The simulations were specially developed for this research and they included many characteristics of an investigative activity. Using a friendly interface, developed under Windows platform (the main screens of each one are presented in Figures 2 and 3, respectively), the simulations showed themselves to be easily understood and useful for the students. All the students participating in the study attended weekly computer classes. Thus, the use of the computer to run the simulations was not a source of difficulties to them. Two simulations were developed approaching two distinct topics (thermal equilibrium and movement on an inclined plane), but with the same structure of variables and procedures. The aim of each investigation was to establish which variables, in a group of independent ones, had influence on a determined dependent variable. In Figure 3. 2. Main screen of the simulation of the ramp thermal problem equilibrium problem Downloaded By: [alessandro@coltec.ufmg.br] At: 11:30 29 November 2007 118 A. D. Trani Gomes et al. Figure 2. Main screen of the simulation of the thermal equilibrium problem communicating this to the students, the aims of the activities were presented in a colloquial and easily understandable way. The aims which were told to the students and other characteristics of the developed investigative activities are presented in Table 2. Among the independent variables there were three causal ones (those that influence the dependent variable) and one non-causal (the one that has no effect on a dependent variable). Two versions of each problem differing only in the number of independent variables (2-var or 4-var) were prepared. This was done attributing some constant values to two out of the four variables, so that students could not modify them in the 2-variable versions of each problem (see Table 2). Throughout the data gathering process, when selecting values for the independent factors, students were asked to write down the reasons for their choices in a dialogue box provided in the screen. Then, after clicking the ‘run’ button, the result was presented in the screen, followed by a brief animation. Next, students were asked to make a remark about the obtained result. When they had done this, they had the choice to go on investigating, i.e., they could either choose another set of parameters and carry out another experiment or leave the programme. When leaving the simulation, all the data, justification and comments were saved in a log-file to be analysed. Through this data, which represent the investigation history, one can know Downloaded By: [alessandro@coltec.ufmg.br] At: 11:30 29 November 2007 Students’ Performance in Investigative Activity and Their Understanding 119 Figure 3. Main screen of the simulation of the ramp problem whether the students carried out good tests, how many tests they did, and what they were thinking during their investigation, revealing features of the strategies they used to conduct each task. Table 2. Characteristics of the investigative activities No. variables Theme Aim Thermal equilibrium To determine which factors influence the final temperature of the system 2 To determine which factors influence on the time it takes for the spheres to slide down the slope 2 Ramp 4 4 Factors/Variables Kind of variables Surface area of the block Temperature of the liquid Surface area of the block Temperature of the liquid Kind of liquid Mass of the block Distance Mass of the block Inclination Friction Discrete (20 levels) Integral Discrete (20 levels) Integral Nominal (3 levels) Discrete (10 levels) Integral Discrete (20 levels) Integral Discrete (20 levels) Nominal (3 levels) Discrete (6 levels) Downloaded By: [alessandro@coltec.ufmg.br] At: 11:30 29 November 2007 120 A. D. Trani Gomes et al. The investigative tasks used in this study were designed to promote an opportunity to observe the research strategies that students used in a context in which their previous knowledge and the ‘sense of mechanism’ are very strong (diSessa, 1993). Besides this, they also make it possible to analyse how these strategies evolved or were modified over the course of the activities. As in other studies (Klahr, Fay & Dunbar, 1993; Penner & Klahr, 1996) we planned tasks which required the students to coordinate their searching both in the experimental space and in the hypotheses space, as well as the evaluation of the evidence produced during the experiment. This represents all the three major processes involved in the SDDS model proposed by Kahr and Dunbar (1988). Test on the Aim of the Achieved Tasks The last phase of the data gathering process consisted of individually answering a question about the aims of the investigative activities. The question asked after the conduction of the second investigation was: ‘You have just conducted an activity through a computer simulation. In your own words, write down what was the aim of the computer simulation you have done.’ Procedures The gathering of the empirical material occurred during the class time by one of the authors of the study. The 181 students who participated in the study were separated into seven classrooms. However, the analysis focuses on the 78 pairs who did all the activities and tests. Students were given 100 minutes to conduct each investigation. The topic order of the investigative activity varied from class to class. Thus, some of the students had activities related to the ‘thermal problem’ on the first day and related to the ‘ramp problem’ on the following day. The other part conducted the activities in the reverse order. The test was answered individually, but students did the investigations working in pairs. The assignment of groups to both problems and their versions of two- and four-variables, was at random, depending on the place in which they had chosen to sit. The option for having students working in pairs was an attempt to simulate the usual approach in science laboratory classes, where students rarely work by themselves. Moreover, there are some clues (Roth, 1995; Meyer & Carlisle, 1996; Kaselman & Kuhn, 2002) indicating that the performance of students when working in duos is frequently of superior quality than when they work individually. Data analysis The Aims of the Activities Given to the Students In order to answer our research questions, we first coded students’ answers to the question about the aim of the task they had completed. A coding framework was Downloaded By: [alessandro@coltec.ufmg.br] At: 11:30 29 November 2007 Students’ Performance in Investigative Activity and Their Understanding 121 developed based on both categories identified in previous studies (Driver, Leach, Millar & Scott, 1996; Welzel et al, 1998) and a preliminary reading of the whole set of data to check the suitability of those categories. The categories of the answers related to the aim of the activity are presented in Table 3. The aims of the activities done through computer simulation were explicitly told to the students. To the ‘thermal problem’, it was to determine which of a set of variables influenced the equilibrium temperature of the system. To the ‘ramp problem’, the aim was to find out which of the involved variables affected the time a sphere takes to get down the slope. A0—The correct aim We considered as correct the answer that had at least one of the aims referred above. Most of the answers that were classified in this way referred correctly to the aim of the former conducted activity. Very few students referred to both activities. Examples: ‘To check what are the physical quantities that interfere with the time spent by the sphere to get down the slope.’ ‘The aim was to identify the factors that influence on the final temperature of the system.’ A1—To confirm hypotheses or theories To define the aim of experimental activities as well as confirming any hypothesis or theory is ordinary enough among students. Many times, the teacher himself contributes to a distorted view of the experimental activities when he proposes, by instance, ‘Check that voltage is proportional to electric current in an ohmic conductor’. To some students, both practical tasks have only one goal, which is to check something we either already know or expect to happen. Examples: ‘To support and to explain the hypotheses or opinions we had on the subject.’ Table 3. Categories of the given answers on the aim of the accomplished task Code Category A0 A1 A2 A3 A4 A5 A6 Correct aim To confirm hypothesis or theories To obtain a given result To evaluate the student’s knowledge To conduct virtual experiments To acquire knowledge from the practice Other different aims Downloaded By: [alessandro@coltec.ufmg.br] At: 11:30 29 November 2007 122 A. D. Trani Gomes et al. The aim was to prove and understand the ideas I have raised in the previous questionnaire.’ ‘To prove whether my thoughts about the influence of mass and distance were correct.’ A2—To obtain a given result To many students, the two experimental tasks have the only one goal: ‘to work well’, i.e., to obtain determined results which are normally already expected. Examples: ‘To get the final temperature of the blocks.’ ‘To verify the temperature averages, the lowest and highest ones.’ A3—To evaluate students’ knowledge Some students answered that the conducted activity aimed at evaluating their knowledge; that is, what they really knew about the theoretical domain in question. In this case, the great majority of them referred to conceptual knowledge, but not procedural knowledge. Examples: ‘[It is] to test our knowledge in a practical way.’ ‘The aim of any experiment is to check what we really know about the topic.’ A4—To conduct virtual experiments The investigative activities were conducted through computer simulations instead of from manipulation of equipments. That was why some students characterised the aim by emphasising the aspect of that different way of conducting an experimental activity. Examples: ‘To conduct experiments we have really done, but this time virtually.’ ‘The goal was to make us foresee, specify the temperature, and, through the experimental procedure, make us write our remarks and conclusions. It is doing all these things using the computer.’ A5—To acquire knowledge from the practice The statements classified here referred to the learning students had got when conducted the activity. Some students answered in a vague and short way, others were specific enough about the conceptual knowledge. Downloaded By: [alessandro@coltec.ufmg.br] At: 11:30 29 November 2007 Students’ Performance in Investigative Activity and Their Understanding 123 Examples: ‘I always think that the major goal of any experiment is to provide knowledge.’ ‘It is to learn more about slopes and temperature’ [sic]. A6—Other different aims Various answers could not be classified in any other category. Some were related to immediate aspects perceived by the students. They referred to particular views of some aspect of the conducted activity. Examples: ‘It is to help Alessandro in his research project.’ ‘To understand in a practical way what happens to the materials.’ We categorised the answers of the 181 students that provided some answer to the aims of the first or the second activity, according this system. However, only 78 duos did the two investigations. Table 4 shows the number of answers and the total percentage for each one of those categories. The first aspect that deserves to be highlighted is the relative difficulty the students had in recollecting the aims of the tasks as they were proposed. Only nearly 60% of them correctly identified the declared aims of the activities even after conducting two investigations with nearly the same aims and structure of variables. Students’ difficulties in understanding the goals had already been realised throughout the activity developments. They were instructed to read carefully the initial screen of the computer simulation. It displayed a description of the activity containing all the necessary pieces of information to conduct it, including the intended aim. But, even with the presentation screen and the explanations orally given by the teacher, while preparing and executing the investigations, many of the groups of students still asked what they had to do. Although most of the participants had limited previous experience in practical classes, the confirmatory view of the school science laboratory as assigning to experiments and observations the aim of proving or verifying some determined Table 4. Category A0 A1 A2 A3 A4 A5 A6 Total Number and percentage of answers by category. Number of answers Percentage 108 23 11 6 5 4 24 181 59.7 12.7 6.1 3.3 2.8 2.2 13.3 100.0 Downloaded By: [alessandro@coltec.ufmg.br] At: 11:30 29 November 2007 124 A. D. Trani Gomes et al. hypothesis, or a theory, is well spread out among the students. In fact, 12.7% of the total number of students (or 31.5% of students who incorrectly answered the questions about the aims of the activity) had their answers categorised as A1. This can indicate a strong belief that school practical activities, and even the scientific ones, are conducted to check hypotheses and theories. This distorted view of the experimentation process can be attributed, perhaps, to the excessive unquestionable nature of science practical activities normally conducted in schools. Additionally, it can be attributed to the characterisation of both the scientific knowledge and the scientific activities by the media and books, including science textbooks (Carey et al., 1989; Solomon, Duveen & Scott, 1994; Tsai, 1999). Practical work developed in schools usually aims only at illustrating phenomena studied in theory or at demonstrating ‘the truth’ of scientific laws. Therefore, students get the view that the experiment always ‘will work’ according to the theory, and the results which will be obtained are always predictable (Category A2). One of the reasons pointed out by literature to explain the low level of students’ learning from practical tasks is indeed their frequent unawareness of the purposes of the activities they do. Tamir (1991), as well as many other researchers (for instance, Sá & Borges, 2001; Hart et al, 2000), states that the aim perceived by the students when conducting a practical activity is different from the aim intended by the teacher, and that students may not understand the relationship between a task purpose and the procedures adopted during the class. The analysis of the files containing the history of the investigations conducted by each pair of students showed that, in several moments, various pairs attributed aims different from those conceived for the activities. Many of the identified aims were completely different and far away from the aims originally intended. Before doing each experiment, as we have already presented in the methodology, students had to assign values to some variables. They were also supposed to predict the result. In many historic files, it was possible to identify answers such as: ‘To check the maximum time it takes the sphere to get down the slope.’ ‘To obtain the higher temperature possible.’ The occurrence of these answers is consistent with the results obtained by Schauble, Klopfer and Raghavan (1991) that many times students did not consider the proposed aims of the task and considered other more practical ones, which is a characteristic of the ‘engineering model’ of investigation. However, the fact of considering more practical aims itself does not prevent students from conducting the task satisfactorily, since some care is taken and they plan adequate and consistent tests to identify the variables that really influence the independent variable. The Relationship Between the Identification of the Aims and the Performance in the investigations To explore any possible relationship between the way students understood the aims of the tasks and their performance in conducting the investigations, all the duos were Downloaded By: [alessandro@coltec.ufmg.br] At: 11:30 29 November 2007 Students’ Performance in Investigative Activity and Their Understanding 125 Table 5. Number and percentage of answers by category Code/Category Description BC OC Duo in which both students correctly identified the aims of the activities. Duo in which one student correctly identified the aims of the activity whereas the other incorrectly done it. Duo in which both students incorrectly identified the aims of the activity. BI divided into three groups according to the way each student of the pair recollected the objectives of the activities done, as shown in Table 5. The second investigation history was analysed for the 78 pairs of students who completed both investigations and answered the other instruments developed for the entire research. Table 6 shows the number of duos coded according the categories of in Table 5 and to the type of their second task. From now on we are considering only data from the second task done by each duo. From the second investigation history we obtained the number of experiments conducted by each pair of students (following the classification presented in Table 5). Then, we identified, how many of the tests conducted could be considered as consistent and adequate to the task aim. An investigation score, defined as the proportion of good experiments in the second investigation, was calculated for each pair of students. A higher score indicates that most of the duo’s experimental tests done are consistent and relevant to solving the problem. On the contrary, a low score means that students do not run good experiments to test their hypotheses, because they do not understand what they are expected to do, or else, because they cannot distinguish uncontroversial and relevant tests to solve the problem. One test consists of assigning values to the independent variables and then running the simulation to obtain the corresponding value of the dependent variable. The total number of tests done is not a good indicator of students’ performance in conducting practical investigations, because on some occasions students may not engage in searching for an empirical solution for the problem (Gomes, 2005). Some of them think they already know the answer and that only a few tests are needed to solve the problem. This might be related to good conceptual understanding of the matter or to deeply entrenched alternative conceptions about it. Table 6. Number of duos according to the activities and their categorisation Number of duos per category Activity Thermal equilibrium Ramp Total Number of variables BC OC BI 2 4 2 4 8 9 5 11 33 5 10 7 4 26 7 4 4 4 19 Downloaded By: [alessandro@coltec.ufmg.br] At: 11:30 29 November 2007 126 A. D. Trani Gomes et al. Table 7. Total number of experiments done and mean investigation score (InvS) Total number of tests done and mean investigation score BC Activity Thermal equilibrium Ramp OC BI Number of variables n InvS n InvS n InvS 2 4 2 4 26 71 21 60 0.61 0.77 0.55 0.68 18 67 27 21 0.55 0.67 0.62 0.67 26 16 14 31 0.56 0.20 0.59 0.46 On the other hand, there are groups that get confused and decide to do an excessive number of tests. Some of these tests are good ones, but students seem unable to draw conclusions about the contribution of their actions to solving the problem. Table 7 shows the total number of tests done according to group of understanding of task aim, as well as the mean investigation score. Table 8 presents descriptive statistics of duos’ investigation performance. We aimed at investigating the possible relationship between the way students recollected the aim of a practical problem and the students’ performance in conducting an investigation to solve it. The problem investigated had no effect on the average performance. In order to look whether duos’ investigation performance was affected by their correct recalling of the task aim a non-parametric Kruskal–Wallis test was initially conducted. Differently to ANOVA, Kruskal–Wallis statistic does not require a normal distribution of the dependent variable for each value of the independents. Kruskal–Wallis resulted in H = 8.937 (df = 2, n = 78), which is statistically significant at the level p=0.011. Levene’s test showed that variances were not homogeneous (see Table 9). An independent sample ANOVA showed significant differences among group investigation-score means (F (2,75) = 5.308, p=0.007), as shown in Table 10. A Games–Howell post-hoc test was chosen as it is appropriate for multiple comparisons of means of groups of different sizes and with unequal variances (Table 11). Table 8. Descriptive statistics—investigation score 95% Confidence Interval for Mean BI OC BC Total n Mean Std. Dev. Std. Error Lower Bound Upper Bound Min Max 19 26 33 78 .465 .635 .662 .605 .274 .216 .176 .229 .063 .043 .031 .026 .333 .547 .599 .553 .598 .722 .724 .656 .000 .000 .290 .000 .750 .880 .860 .880 Downloaded By: [alessandro@coltec.ufmg.br] At: 11:30 29 November 2007 Students’ Performance in Investigative Activity and Their Understanding 127 Table 9. Levene Statistics—investigation score Levene Statistic 2.398 df1 df2 Sig. 2 75 .098 Two interesting aspects can be distinguished in Table 11. First, there is no significant difference between mean investigation-scores of groups OC and BC. A possible explanation is that if at least one member of the duo understands the aim of the task (OC), this student can conduct or lead the execution of the activity. So, the duo would not show significant differences compared with the duos where both students understood the aim of the activity BC. On the other hand, the performances in conducting the investigation of the duos characterised as BI are, in general, worse than those of BC and OC duos. In fact, Table 11 indicates statistically significant differences only between groups BI and BC. This means that the BI duos, in which neither student has understood the aims of the activities when asked individually, had their performance compromised. Eta-squared amounts to 0.124, which means that understanding of task objectives explains 12.4% of the variance in all duos investigation-scores (Table 12). In order to clarify what makes a difference in students’ performances, the duos were selected according to the number of variables in their second task, and an independent sample ANOVA conducted on each case. Tables 13 and 14 show the mean investigation-score differences between the groups carrying out investigations in tasks with two and four variables, respectively. Table 13 indicates that there is no significant difference in performance of duos investigating a problem limited to two independent variables (F(2.33)=0.265, p=.769). Post-hoc comparisons display the same pattern and are not include here, for the sake of brevity. For those duos investigating problems with four independent variables, the situation changes drastically. Table 14 indicates a differentiation in groups’ performances. Group means show significant differences, as indicated by ANOVA (F(2.39) = 7.126, p=.002). This indicates that those duos that were able to recall the declared aims of the tasks after doing them showed better performance in more complex investigative tasks. Post-hoc comparisons (Table 15) show significant differences between BI and OC group means, at the level p=0.01, and between BI and BC group means (p=0.002). Tukey HSD test was used as pos-hoc test because in the case of sub-groups working with four variables the variances across groups are equal. In all the cases, Welch and Brown–Forsythe tests were also conducted and corroborated the results presented. Eta-squared in this case Table 10. ANOVA for investigation score, including all duos Understanding of second task objective Error Total Sum of Squares df Mean Square F Sig. 0.499 3.527 4.026 2 75 77 .250 .047 5.308 .007 Downloaded By: [alessandro@coltec.ufmg.br] At: 11:30 29 November 2007 128 A. D. Trani Gomes et al. Table 11. Post hoc test—multiple comparisons, including all duos, for the investigation score 95% Confidence Interval (I) Understanding of task objective (J) Understanding of task objective Games–Howell BI JOC BC Mean Difference (I–J) Std. Error Sig. Lower Bound Upper Bound −.169 −.196* .169 −.027 .196* .027 .076 .070 .076 .052 .070 .052 .081 .025 .081 .865 .025 .865 −.356 −.370 −.017 −.154 .022 −.100 .017 −.022 .356 .100 .370 .154 OC BC BI BC BI OC * The mean difference is significant at the .05 level. increased to 0.268, which appears to be very high, taking into account the host of other variables at individual and social levels beyond control in educacional and social research. To obtain more evidence about the influence of the understanding of the aim on conducting an investigation, we analysed the files containing the history of investigation of each pair of students. They were coded according to the categories of quality of investigation presented in Table 16. This categorisation is concerned overall with the management of the experimental domain, and with the use of adequate and consistent experimental tests. Therefore, the data obtained from this categorisation inform us about the general quality of the activity achieved by the duos. Table 17 shows the distribution of the number and percentage of student duos according to the categories presented in Table 16, as well as with the identification of the aims of the activities. The data presented in Table 17 indicate that the quality of the investigation conducted by the students improves with the understanding of the aims of the activities. Once more, the quality of the investigation conducted by BC and OC duos are similar and relatively better than those from BI duos. Assuming the SDDS model (Klahr & Dunbar, 1988), we can also provide a plausible explanation for the results obtained. The investigations with two variables present limited experimental and hypothesis spaces, and thus they seem easier to all students. On the other hand, in activities with four variables both the experimental and the hypothesis spaces are larger and thus more demanding. Table 12. Investigation score * Understanding of task objective Measure of association including all duos R R Squared Eta Eta Squared .320 .102 .352 .124 Downloaded By: [alessandro@coltec.ufmg.br] At: 11:30 29 November 2007 Students’ Performance in Investigative Activity and Their Understanding 129 Table 13. ANOVA for investigation score, for problems with two independent variables Understanding of second task objective Error Total Sum of Squares df Mean Square F Sig. .020 2 .010 .265 .769 1.273 1.293 33 35 .039 The answer to our research question is positive. Students from the first year of Brazilian middle school (which is their ninth year of basic schooling) planned and developed experimental tests relevant to the solving of the task they were conducting, while adopting appropriate variable control strategy. The overall mean investigation score was .605, ranging from .465, in the case of duos with no understanding of task aim, to .662 in the case of group BC where both members of the duo got the task objective as intended (see Table 8). In the simpler task with two independent variables, those figures rose to 0.540 for BI and 0.593 for the group OC performing better than BC group. In the activity with four independent variables, the mean score of BI duos was 0.363, while BC duos reached a mean score of 0.708. We have no data concerning students’ performance in doing investigation before middle school, but most of them have never had practical work of this kind before. The more likely is that they had only observed their science teacher doing demonstrations. Data for this study were collected at the beginning of the last term of the school year and the involvement of students in conducting more open tasks in the physics lab during the first and second term have afforded them invaluable learning opportunities. About 60% of the participants were able to recall the aims of the tasks as they were declared. The findings that about 13% of them identified objectives to the tasks as category A1 (to confirm hypotheses or theories), and as category A6 (other different aims) were expected. These figures suggest that BC duos showed more engagement in the more complex task. In fact, Gomes (2005) shows that BC duos solved most of the simpler problems by relying on their knowledge of the concepts underlying the task, whereas the BI group did a lot more exploration, even in simpler tasks. This might be the reason why students’ performance in investigating the simpler independent problems did not show any significant difference among the groups. However, in the Table 14. ANOVA for investigation score, in the case of four independent variables for investigations Sum of Squares Understanding of second task objective Error Total df Mean Square F Sig. .717 2 .358 7.126 .002 1.961 2.677 39 41 .050 Downloaded By: [alessandro@coltec.ufmg.br] At: 11:30 29 November 2007 130 A. D. Trani Gomes et al. Table 15. Multiple comparisons, for investigations with four independent variables 95% Confidence Interval (I) Understanding of task objective (J) Understanding of task objective Tukey HSD BI OC BC OC BC BI BC BI OC Mean Difference (I–J) Std. Error Sig. Lower Bound Upper Bound −.308* −.346* .308* −.038 .346* .038 .099 .094 .099 .078 .094 .078 .010 .002 .010 .878 .002 .878 −.550 −.574 .065 −.228 .117 −.152 −.065 −.117 .550 .152 .574 .228 * The mean difference is significant at the .05 level activities with four variables, the attempt to coordinate the investigation in both experimental and hypothesis spaces is more complex and demanding. The investigation score of BI duos decreases as the number of variables involved increases, in contrast to the other groups. Concerning the second research question, our findings suggest that students’ performance in planning and conducting investigations to solve a practical problem is correlated to their ability to recall the aims of the activities they have done. The correlation is stronger in the case of more complex problems, that is, involving more variables. The overall quality of investigations conducted by the participants of this study was very good considering their prior experience with this type of task. However, when having even an inadequate understanding of the declared aims of the task, it is more likely that students can show satisfactory performance in conducting simpler investigations, due to the small number of experiments they need to do to collect information for advancing to a conclusion. Final considerations Science educators (AAAS, 1990; Millar, 1991; Minstrell and van Zee, 2000) argue that science education should involve not only the development of comprehensive Table 16. Categories used to classify the investigations conducted by the students Category Description Very good Acceptable When the duo conducted at least one adequate and consistent test for all variables. When the duo conducted at least one adequate and consistent test for at least 50% of the variables. When the duo conducted the majority of the experimental tests in an inconsistent way and investigated the influence of few variables. Inadequate Downloaded By: [alessandro@coltec.ufmg.br] At: 11:30 29 November 2007 Students’ Performance in Investigative Activity and Their Understanding 131 Table 17. Distribution of the number and percentage of students’ duos according to the quality of the investigation and the identification of the aims of the activities Number and percentage of students’ duos in each categories for the identification of the aims BC OC BI Quality of the investigation n % n % n % Very good Acceptable Inadequate Total 20 9 4 33 61 27 12 100 16 8 2 26 62 31 7 100 8 5 6 19 42 26 32 10 0 and abstract knowledge, but also of practical and contextual knowledge. In this way, students would not only construct an effective scientific culture, but also develop the capacity for interpreting, analysing and understanding their observations and experimental results. One of the ways to get such teaching is the creation of an environment which allows promoting the development of an investigative, critic and creative attitude toward novelty, attempting to build an understanding for new situations and phenomena which we deal with at any moment (Borges, Borges & Vaz, 2001, p.2). If we believe that investigative activities can contribute both to more and better science and to knowledge about science learning, we should be aware of the fact that students face many difficulties of both a conceptual and procedural nature. One of the sources of these difficulties is exactly the scarce attention teachers give to communicating what they intend students to learn with practical activities and the consequent failure of students to figure out the aims of the experimental activities they conduct and what things they are supposed to learn by doing them. This contributes to students performing more poorly than they could. Thus, it is important to study how the different ways students understand the declared aims of the tasks they are doing affects their actions and thinking in the science laboratory. This could support the production of pedagogic strategies to improve their learning from practical work. Our results show that some of the students of the observed group had significant difficulties in understanding the stated aims of the activities they did, thus having their performance affected. Students who understand well the intended aims of the activities tend to conduct better investigations, as measured through both the scope of searching in the experimental space and the use of adequate and consistent tests. The data also make it clear that getting the aims of laboratory work wrong can exert great influence on students’ performance. This effect is milder in simpler activities and increases with task complexity. Therefore, when planning practical Downloaded By: [alessandro@coltec.ufmg.br] At: 11:30 29 November 2007 132 A. D. Trani Gomes et al. activities, science teachers should consider that students can attribute other aims rather than those intended and declared. Teachers should also be aware that this could result in students’ performance being poorer than they are capable of. Thus, teachers should do their best to make sure that students have a clear understanding of the purposes of each activity, the reasons for doing it, and for using consistent experimental strategies to obtain the kind of data appropriate for solving the task. From the results of this study, we defend the importance of teachers favouring the conduction of pre-lab discussion to make explicit what will be done during the activity and how, as well as the intended practical and pedagogical aims. In the same way, at the end of the practical activity, teachers should promote the discussion of the obtained results having in mind the initial proposed aims. The engagement of students in both these tasks can contribute to helping them to get a more suitable understanding of the experimentation process and to establish connections between the activities’ aims, the actions, the adopted procedures, and the results. In this way, the actions, attitudes and procedures of students during the tasks should be discussed and analysed, so that they can develop a conceptual understanding of experimentation and their fundamental procedures. Students should have the opportunity to realise that: (i) the methods and the procedures used depend on both the nature of the problem and the proposed aims; and (ii) the obtained results as well as what has been learnt also depend directly on the process of investigation conducted. As we previously discussed, students face difficulties in correctly identifying what they are supposed to learn from the tasks they conduct in the school laboratory. This difficulty seems to be related not only to an inadequate understanding of the role of the laboratory and experimental activities in education, but in science itself. The empiricist idea that laboratory activities aim at proving theories or laws is disseminated among students and stressed by science teachers and textbooks. In conclusion, the present study points to questions that have neither been satisfactorily answered nor comprehensibly investigated, but that directly influence the whole planning and execution of investigative activities processes. Among these questions, we can emphasise: ● ● ● How do students understand the experimentation process? How do their views about science and experimentation influence their performance during experimental activities? How do students understand the production of knowledge from the experimental activities? These questions relate themselves directly to individuals’ views of science, scientific knowledge, and experimentation. According to Ryder, Leach and Driver (1997), the Downloaded By: [alessandro@coltec.ufmg.br] At: 11:30 29 November 2007 Students’ Performance in Investigative Activity and Their Understanding 133 formal discussion in classroom about subjects related to the nature of science is not usual. Thus, students rarely come to integrate—orally or in writing—what they understand as science or scientific knowledge. So, the comprehensions that students have about the nature of science and the production of scientific knowledge are mostly tacit, formed from the general media and from particular experiences inside and outside school. 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