Epistemological problems underlying pre-service chemistry teachers’ aims to use practical work in school science

Abstract

The main purpose of this study is to explore the epistemological problems underlying pre-service chemistry teachers’ aims in using practical work, i.e., individual or small group object manipulation or observation, in school science. Twenty-two pre-service chemistry teachers participated in this study. Qualitative data collection tools included participants’ reflections about some practical work cases; participants’ practical work plans; responses given to open-ended questions about practical work, scientific inquiry, the epistemology of science, and science teaching approaches such as discovery and inquiry based learning; and follow-up interviews. Through the qualitative analysis of the data, participants’ aims were grouped under three main themes, which included six categories: providing learning by discovery to students, serving to verify scientific theory, making scientific theories concrete, developing students’ scientific process skills, providing learning about the nature of science, and creating curiosity and motivation towards science. Arguments related to any epistemological problems underlying some of these aims are presented in the Results and discussion section. Based on the results, conclusions were made about the sources of these epistemological problems, why the epistemology of science should be considered explicitly when teaching the science teaching approaches and using the practical work, and why “teaching nature of science implicitly” failed.

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Introduction

For the purposes of the current study, practical work is defined as “any science teaching and learning activity in which the students working individually or in small groups observe and/or manipulate the objects or materials they are studying” (Millar, 2010, p. 109). Science education researchers focusing on the role and importance of practical work emphasized that much of the practical work in science lessons was missing an important piece, namely, the epistemology of science (Hodson, 1990, 1996; Kirschner, 1992; Millar, 1998, 2010; Chinn and Malhotra, 2002; Wickman, 2004; Sandoval, 2005; Berland et al., 2016). Specifically, certain researchers highlight epistemological problems related to the reasons or aims for using practical work in school science. For example, according to Kirschner (1992), some school science practical work, such as experimentation, is used to verify scientific knowledge (e.g., theories, principles, and concepts). Experiments are frequently used in science lessons and hence inevitably affect students’ understanding about the role of experimentation in scientific discovery and science careers. However, conducting experiments with the goal of verifying a scientific theory is not compatible with science epistemology. In reality, there is an interrelated and interactive relationship between experiments and theory in authentic science (Kirschner 1992, Hodson 1998); although experiments are important for the development of a theory, they should not be considered as independent confirmation of theoretical principles. Use of experiments with these epistemologically poor aims may cause misunderstandings in terms of the role and importance of experiment and theory, and the relationship between them. Unfortunately, the vast majority of experiments in schools are usually planned to serve as verification for a theory, and are mainly focused on the development of students’ experimentation skills (Kirschner, 1992).

The reason for use of the term “practical work” rather than “experimental or laboratory work” in this study is related to this kind of epistemological problem. An experiment, in terms of the epistemology of science, is generally taken to mean a planned intervention to test a prediction derived from a theory or hypothesis (Abrahams and Millar, 2008). However, many experiments in school science do not function in this way. In addition, the term “practical work” is, in the case of a school setting, more appropriate than “laboratory work” since it involves activities carried out not only in a laboratory but also in and out of the classroom (Millar, 2010).

Conceptual framework

Defining the epistemology of science

“Epistemology is the name of a branch of philosophy dedicated to the theory of knowledge” (Siegel, 2014, p. 372). When this definition is adapted to science, the epistemology of science is an area of philosophy that deals with both the nature of scientific knowledge and the scientific justification of knowledge claims. It seeks to find answers for the fundamental questions given below:

• What is scientific knowledge, and what do we mean when we say that we know something in science?

• What is the source of scientific knowledge, and how do we know if it is reliable?

• What is the scope of scientific knowledge, and what are its limitations?

In science education, the development of students’ understanding of the epistemology of science relates to the development of their understanding of the nature of scientific knowledge and scientific inquiry. Some science educators group these epistemological views of science under the more general concepts of the “nature of science” (NOS) and nature of scientific inquiry (NOSI) (Schwartz et al., 2008). Since the NOS and NOSI involve not only epistemic but also social–institutional aspects of science such as “social organizations and interactions”, “political power structures”, and “financial systems” (Erduran and Dagher, 2014, p. 143), it is useful to distinguish epistemic understandings from other understandings related to the nature of science for this study.

Epistemological problems in science teaching approaches

When the history of science education curriculums in any developed country is investigated, certain reforms or innovations can be seen under the name “discovery learning” in the 1960s, “process approach” in the 1970s and “constructivist approach” during the 1980s and early 1990s. In this discovery learning approach, it is assumed that students can discover conceptual knowledge through practical work that mimics scientific research (Hodson, 1996). This approach has since then been criticized due to the assumption that students have prior knowledge before learning new content knowledge (Kirschner, 1992). Kirschner argued that without providing prior knowledge or a theoretical framework to students, teachers using discovery learning cannot fully explain the new concept to them.

Hodson (1996) stated that the discovery learning approach caused misinterpretations of the nature of scientific inquiry and thus contributed to students’ misunderstanding about the epistemology of science. Similarly, Kirschner (1992) noted that some curriculum developers and reformers could not distinguish the difference between “teaching of science as inquiry” and “teaching of science by inquiry.” Teaching science as inquiry emphasizes the scientific process when learning and teaching science. Teaching science by inquiry puts the scientific process into use during the teaching of science. Roehrig and Luft (2004) claimed that how teachers interpret inquiry-based teaching models and adapt them to their students’ needs affects lessons’ representation of “science as inquiry.”

Process-oriented learning is another frequently criticized approach to science teaching. Critics argue that, within process-oriented learning, scientific content knowledge seems to be less important than developing scientific inquiry skills. Hodson (1996) pointed out that there are some assumptions underlying this approach:

• “Scientific inquiry can be described in terms of a series of discrete processes.

• The processes are generic. That is, they are context-independent and, therefore, transferable.

• Scientific knowledge results from engagement in these processes.

• [The] performance of these skills can be readily observed and accurately and reliably measured.

• By practicing and developing these skills, students acquire the capacity to conduct scientific inquiries” (p. 122)

Hodson (1996) claimed that teachers do not intrinsically teach processes such as observation, classification, and hypothesizing because they have already experienced them many times in their daily life outside of science lessons and laboratories. What teachers should teach in school science, according to him, is “scientific observation, scientific classification, [and] scientific hypothesizing.” He continues, “what makes these processes scientific is the utilization of relevant and appropriate science concepts in pursuit of scientific purpose[s]” (p. 117).

Another point of criticism toward the process approach is related to its generic nature. From the perspective of theory-ladenness, having a student acquire some skills—such as observing, classifying, or measuring—within a context does not mean that the student can use those skills in another context. In short, it is not possible to engage in these processes independently from content. As Hodson (1996) said, “The skills involved in observing the behavior of aquarium fish, for example, have little (if any) relevance to observing the behavior of chemicals on heating, observing distant nebulae through a telescope, or ‘reading’ X-ray photographs” (p. 126). Therefore, for a teacher, it is important to consider whether a student can transfer a scientific process skill from one context to another. Although Hodson refers to completely different contexts in the quote above, even skills that are exhibited in the same context but in different subjects may not be transferrable.

In recent years, in the US, a new framework for science education (A Framework for K-12 Science Education, 2012) and new standards based on this framework (Next Generation Science Standards-NGSS, 2013) have been developed. The 2012 Framework presents three dimensions of learning: Science and Engineering Practices, Crosscutting Concepts, and Disciplinary Core Ideas. The Framework uses the term “practices,” rather than “science processes” or “inquiry skills,” because “engaging in scientific investigation requires not only skill but also knowledge that is specific to each practice” (National Research Council Framework, 2012, p. 30). The framework includes a criticism about the relationship between practices and content that has not been reflected correctly in earlier standards. It emphasizes that practices and content should not be considered as separate entities. Instead, practices and content are always in union in both science and engineering.

The process view and constructivist approach share many similarities and thus many of the same issues. Millar (1998) indicated that there are some epistemological problems with the “inquiry learning” view, which is often emphasized within the constructivist approach. One of them is the assumption that “the collection of data, through observation and measurement, is a straightforward common-sense activity” (p. 18). Millar explained why this assumption is problematic in terms of epistemology, in the following way:

In practice, however, any natural object, material or event has so many features and aspects that any observation of it must begin with a selection process, deciding what to observe and what to ignore. This selection is based on a view about what is salient to observe; in other words, it embodies a particular stance, or perspective, on the thing being observed. Also the quantities (or variables) we use in making and recording our observations are not ‘given’ by the phenomenon; they are part of the framework of ideas that we bring to the act of observation. So we cannot approach anything and ‘just observe it’; we always bring our own particular set of ‘spectacles’ to the act of observing (p. 18).

The other problem mentioned by Millar is the question of “how to get from observations to explanations” (p. 19). He claimed that inquiry learning is based on naïve inductivism, since it is established in the idea that “explanations will ‘emerge’ from observations, if these are carefully structured and sequenced by the teacher and the teaching scheme” (p. 19).

The faulty assumptions and epistemological problems related to science teaching methods can be serious obstacles to learning both the content knowledge and epistemology of science for students. Therefore it needs to be investigated whether or not science teachers or pre-service science teachers have such assumptions and problems. For this investigation, determining their aims to use practical work plays a key role because practical work seems to be a common aspect of both science and science education.

Epistemological problems in practical work

Practical work is generally used as a tool for the implementation of the above science teaching approaches, such as discovery learning, process-oriented learning, and inquiry-based learning in science lessons. Therefore, the faulty assumptions and epistemological problems underlying these approaches can also be reflected in the teacher's goals regarding practical work.

Kirschner (1992) asserted that there are some faulty motives for implementing practical work. He also explained the relationship between these motives and the epistemological problems underlying the faulty assumptions of the teaching approaches discussed above. According to him, some teachers use practical work because it is important and valuable; it serves the understanding of scientific theory. Therefore, practical work is frequently used for verification or confirmation of a theory. Kirschner (1992) emphasized that there are two basic epistemological problems related to this motive. The first problem is that practical work is “subservient to the theory” (p. 280). Using practical work such as experiments in school science to understand and conceptualize a theory causes some misconceptions about the epistemology of science. In professional science, experiments are not subservient to scientific theories. There is an interdependent and interactive relationship (Kirschner, 1992). If experiments are conducted to help students understand a theory that they learned beforehand and the connections between the theory and the variables in the experiments are ignored, the students may tacitly believe that there is a hierarchical order in which theory trumps experiment. Thus experiments in school science should not be treated independently from theory, or vice versa. The second problem emphasized by Kirschner is that practical work can help students to make abstract concepts concrete. Woolnugh and Allsop (1985) originally described why this is a problem in terms of the epistemology of science as follows:

Science deals with theoretical concepts and their interrelationships. They are abstract and have to be considered and manipulated in the abstract. It is essential that these concepts are separated from their concrete reality if the maturing scientific mind is to gain mastery of them. We mislead and restrict the thinking of students when we give the appearance of relating everything to a laboratory experience (p. 39).

The second motive for implementing practical work is the belief that “discovery (preferably in a laboratory) is synonymous with and is thus the only way to achieve meaningful learning” (Kirschner, 1992, p. 281). Problems with discovery learning were discussed above. The issue with this belief is the idea that practical work provides meaningful learning because it is used for discovery learning. The sources of this faulty motive, according to Kirschner, can be found in the misinterpretation of ideas about the psychology of meaningful verbal learning proposed by David Ausubel (for further discussion see Kirschner, 1992).

This belief, that students can directly infer the explanations from observations made in practical tasks, is the third motive mentioned by Kirschner (1992). This motive is also problematic in terms of the epistemology of science as clarified by Millar (1998):

We can, for instance, make many observations about the behavior of rubbed plastic rods and other objects, noting how they attract and repel, and stick to other objects. These observations do not inevitably lead to the conclusion that some invisibly small particles are transferred between objects in the process of rubbing, and that these particles carry an electrical charge—a fundamental property of matter that is not normally observed because it exists in positive and negative forms which are usually present in equal amounts (p. 19).

These epistemological problems of practical work are not just based on assumptions. Issues with practical work are understood from curriculums and textbooks. For example, Bencze (1995) asserted that science curriculums create two types of illusions for students. The first illusion, called the “illusion of certainty” by Bencze, deals with the belief that “laws, theories and inventions of science and technology, and methods used to establish them, are certain” (p. 11). He pointed out some sources of this illusion: (i) omission of epistemological justification, combined with an excessive focus on transmitting easily measurable content knowledge; (ii) use of ‘recipe-style’ laboratory ‘experiments’ to justify knowledge claims, without any appropriate debate, and/or to simulate scientific ‘discovery,’ without any mention of their theory-dependence; and (iii) omission of correlational studies (p. 1).

The second type of illusion presented by school science is the “illusion of indispensability” (p. 1). It refers to the belief that there is a one-way relationship between science and technology. Namely, technology is considered as an application of science or vice versa. This is a faulty thought because there is an interdependent and interactive relationship between them and one cannot compel the other. Bencze (1995) pointed out some sources of this illusion: “(i) the ordering of course content from theoretical to practical; and (ii) omission of technological design activities” (p. 1). Relatedly, he noted the lack of student opportunities to design their own inventions or experimentations in a more open-ended setting as a flaw in the curriculum.

Chinn and Malhotra (2002) argued that many practical tasks based on inquiry learning in school science do not reflect the central features of authentic scientific reasoning. In their studies, the inquiry-based activities in various science textbooks fell into three categories: simple experiments, simple observations, and simple demonstrations. They compared these activities with authentic scientific activities in terms of the cognitive process and epistemology of science. They showed that the activities in science textbooks do not reflect some aspects of authentic scientific activities in terms of the epistemology of science, including “the purpose of research, theory-data coordination, theory-ladenness of methods, responses of anomalous data, nature of scientific reasoning, [and] social construction of knowledge” (p. 188).

It seems that pedagogical understanding about science teaching approaches and the use of practical work based on these approaches is closely related to epistemological understanding. Therefore, it is important to explore what in-service and pre-service teachers think about these teaching approaches and what their aims are in using practical work in terms of the epistemology of science.

Research on aims to use practical work

There is an existing body of research determining teachers’ reasons and rationales for doing practical work (e.g.Kerr, 1963; Beatty and Woolnough, 1982; Hofstein and Lunetta, 1982; Welzel et al., 1998; Abrahams and Saglam, 2010; Lewthwaite, 2014). The European Commission funded the international research project “Labwork in Science Education” (LES) between 1996 and 1998. One of the aims of the LES project was to develop a comprehensive conceptualization of the aims of practical work. Welzel and her colleagues (1998) from the LES project investigated teachers’ objectives for labwork in different European countries, across various levels and subjects. They developed a survey tool to gather empirical data about teachers’ objectives for labwork according to the Delphi technique, including 5 main categories and 33 subcategories of objectives. The main categories formulated were: for students (a) to link theory to practice, (b) to learn experimental skills, (c) to get to know the methods of scientific thinking, and (d) to foster motivation, personal development, and social competence, and—for teachers—(e) to evaluate the knowledge of the students. One of the subcategories related to the first category was “to verify scientific laws.” Similarly, Abrahams and Saglam (2010) later examined whether there had been any changes in the relative importance of the aims that science teachers (n = 393) assign to the use of practical work, since the last such national survey undertaken by Kerr 46 years ago. In both studies, it was found that teachers have similar aims, such as to make physical phenomena more real through actual experience and to verify facts and principles already taught. Finally, Lewthwaite (2014) examined teachers’ reasons for performing a demonstration or having students do an experiment and carry out an investigation. He categorized the reasons under three broad categories: pragmatic, psychological, and philosophical. One of the teachers’ reasons for doing experiments, categorized as “psychological,” was to “elucidate key ideas … to verify a chemistry concept” (Lewthwaite, 2014, p. 40).

Most of the studies determining the aims of practical work have the following common aspects:

• The aims are usually given in advance and teachers are required to rank them (except for Lewthwaite's study).

• Teachers’ aims are similar.

• There is almost no study on determining pre-service teachers’ aims.

Furthermore, most of these aims have epistemological problems, but they have not been addressed in these studies. Regarding practical work, the aims from the literature are similar to those determined in the present study. However, the present study differs from other studies in that it focuses on the epistemological problems underlying these aims, and explains why they are problematic in terms of the epistemology of science with examples given by pre-service chemistry teachers. The present study will provide significant contributions to science education in general because it determines the epistemological problems underlying the known issues with practical work in the classroom. Because it presents examples of the problems related to practical work, it will also provide significant contributions to the chemistry education field, in which laboratory work is frequently involved.

Methods

Research design

There are two main research questions of this study:

1. Why do PCTs use practical work in their lesson plans?2. Are there epistemological problems underlying PCTs’ aims in using practical work?

This study relied on qualitative inquiry to gain rich data for an in-depth analysis about these aims and if any epistemological problems. As a research design, a case study was used because it provides evidence through a set of procedures for investigating an empirical topic within a naturalistic setting (Yin, 2003). In particular, a descriptive case study was chosen for this study to answer questions based on theory (Yin, 2003). The descriptions of epistemological problems determined throughout the research process will help in defining the theoretical constructs under the science teaching approaches and practical work.

Participants

Data were collected from a convenience sample of 22 pre-service chemistry teachers (15 females and 7 males) attending a course called “Chemical Experiments in Secondary Science Education.” The participants’ ages ranged from 21 to 24. Information about each participant was collected through a participant information form. This revealed that 20 participants had taken elective theory courses, such as History of Science and Philosophy of Science, before the present study. In addition, it was observed that they had similar backgrounds in terms of coursework, including chemistry courses (e.g., Analytical Chemistry and Organic Chemistry) and pedagogical courses (e.g., Classroom Management and Learning and Instruction Theories). They had participated in laboratory works as a student in laboratory courses (e.g., Analytical Chemistry Laboratory, Organic Chemistry Laboratory). They had no internship experience yet.

Data collection

This study relied on qualitative data sources to gain rich data for an in-depth analysis about the phenomenon being investigated. Data collection tools included responses given to open-ended questions about practical work, scientific inquiry, the epistemology of science, and science teaching approaches (e.g., inquiry-based science teaching and discovery learning); reflections about practical work cases; participants’ practical work lesson plans; and follow-up interviews.

The open-ended questions (see Appendix 1) were developed by the researchers after considering the critiques and problems related to both practical work and science teaching methods in school science, as previously described in the literature review (Hodson 1990, 1993, 1996; Kirschner, 1992, 2009; Millar 1998, 2010; Wellington, 1998). The practical work cases were also prepared through the lens of the critiques of practical work. Some cases were developed using the literature (Millar, 1998) (see Appendix 2). The participants were asked to read cases and then answer follow-up questions related to the cases. The participants’ practical work plans were collected to compare their views about practical work with what they aim to do in the classroom. The participants were asked to plan a practical work for teaching a chemistry topic of their choice. Because the open-ended questions and practical work cases influence their practical work plans, the participants were asked to prepare their lesson plans before answering them.

After collection of all data—including responses to open-ended questions, reflections on the cases, and creation of practical work plans—semi-structured interviews were conducted. Interview questions were related to participants’ practical work plans for the most part. For example: What was the aim of this practical work plan? Why did you really use this worksheet in your practical work plan? In addition, questions similar to the open-ended questions given in Appendix 1 were asked at that time to gain deeper understanding about their practical work plans. Because of the time and scheduling challenges involved in interviewing all 22 participants, only 10 participants were interviewed. With the permission of the participants, all interviews were tape recorded and then transcribed verbatim.

Triangulation and member-check strategies were used to establish the trustworthiness of the study (Lincoln and Guba, 1985). Methodological triangulation was used by gathering data by means of different data collection methods such as open-ended questions, practical work plans and interviews. Analyst triangulation was applied by involving research team members in the process of data collection and analysis. In the data analysis, before the coding process, the researchers discussed the category definitions and related epistemological problems, which had been assigned before. The documents (those belonging to five participants) were analyzed by them independently. During the process of analysis they held regular meetings to compare their interpretations. When their interpretations differ, they discussed them until the best represented the meaning of the data. The percentage agreement score was 93%.

Member-checking, also known as participant validation, was used with the aims of checking factual information and also enabling the addition of new data. Member-checking occurred both during the interviews and at the end of the data analysis. During the interviews, the researcher asked them extra questions to understand the unclear expressions of the participants, or told them what is understood, and waited their confirmation. At the end of the study, since it is possible to reach the participants, the findings about their aims to use practical work were shared with them and they were asked to critically analyze the findings and comment on them.

Data analysis

A qualitative data analysis software program, NVivo, was used to organize and work on the data. All the data were stored in the researchers’ computers as Microsoft Word documents and were transferred into the NVivo Document Browser. Before the coding process, several categories (e.g., to verify scientific theory and to make scientific theories concrete and provide visual learning) had been assigned according to the critiques of aims for practical work found in the literature review. At the beginning of the coding process, all documents were read again and notes were taken. During the readings, other coding categories (e.g., to provide learning by discovery and to develop students’ scientific process skills) emerged. The participants’ views and their practical work plans were coded and placed into a category. The aims of practical work were eventually arranged into six categories: (a) providing learning by discovery, (b) serving to verify scientific theory, (c) making scientific theories concrete and providing visual learning, (d) developing students’ scientific process skills, (e) providing learning about the nature of science, and (f) creating curiosity and motivation towards science. A coding scheme describing only epistemologically problematic aims for the use of practical work is given in Table 1.

Table 1 Coding scheme describing epistemologically problematic aims of practical work

Category	Definition	Epistemological problem
To provide learning by discovery	Students can discover conceptual knowledge through practical work without providing any prior knowledge.	Explanatory ideas come from direct observations made in practical work. Students already have prior knowledge to explore explanatory ideas.
To verify scientific theory	Students can verify or confirm a scientific theory through practical work.	Theoretical knowledge is learned in the classroom and then this knowledge is verified and consolidated by practical work in the laboratory.
To make scientific theories concrete and provide visual learning	Students can visualize and make concrete scientific theories through practical work.	Practical work both in science and in science education makes scientific theories concrete.
To develop students’ scientific process skills	Students’ scientific process skills could be developed through practical work.	Scientific process skills are not connected to the content and can be transferred from one context to another. There is a direct relationship between skill development and the number of skill development practices.

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As the codes were gathered into categories, and then the categories were gathered into larger more overarching categories by looking for the interrelationships among them, the following themes emerged: teaching scientific knowledge, teaching scientific processes, and providing affective objectives about science.

Ethical precautions

Ethical approval for the study is obtained from the Institutional Review Board for this study. Twenty-two pre-service chemistry teachers who attended a course called “Chemical Experiments in Secondary Science Education” participated in the study. Before they chose the course, we announced the study during the course presentation. The participants were informed that there was no relationship between participating in the study and assessments or grades in the course, and pseudonyms were used to keep their identities confidential. All the participants who selected the course voluntarily agreed to participate in the study by signing a consent form.

Results and discussion

The number of participants who fell under each theme and category is given in Table 2. Because almost every participant mentioned multiple aims of practical work, participants were included in more than one category. Evidence and arguments concerning epistemological problems underlying some of these aims are presented below.

Table 2 PCTs’ aims to use practical work

Theme	Category	Frequency
To teach scientific knowledge	To provide learning by discovery	17
	To verify scientific theory	12
	To make scientific theories concrete and provide visual learning	7
To teach scientific processes	To develop students’ scientific process skills	5
	To provide learning about the nature of science	1
To provide affective objectives about science	To create curiosity and motivation towards science	4

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To provide learning by discovery

The majority of the participants (n = 17) thought that practical work in school science provides learning by discovery for students. Answers given by one participant (Gül) to various open-ended questions regarding discovery learning and practical work are given below.

Q4-What do you think about discovery learning in science education? What is the purpose of discovery learning? Please explain by giving an example.

Students should learn scientific knowledge by doing and discovering rather than by accessing it directly. The teacher provides students discovery learning by organizing various practical tasks. For example, a teacher comes to the classroom with some materials such as a magnet and some metallic, plastic, and wooden objects. Students are asked to record which of the materials are pulled or not pulled by the magnet. Thus, the students will learn through discovery. (Gül)

Q7-Can students discover a scientific theory by just observing the process? For example, can students discover explanations about dissolution only by observing soluble, insoluble, and poorly soluble substances in water and by collecting enough data on them?

Yes, they can. There is no such thing that a theory will not be explored again after it was explored for the first time. A theory even if previously undiscovered, students could explore it by their own observations and collecting sufficient data. Each student is like a scientist. (Gül)

Q9-Students can be involved in some practical work such as observing, collecting data, and conducting an experiment when they learn new subject matter knowledge. Is it important to learn students’ prior knowledge or conceptual framework and experience before practical work? Why?

Yes, it is important because students’ prior knowledge may be wrong and/or may not be consistent with the subject matter knowledge. Meaningful learning does not occur in this case. (Gül)

Based on the magnet example given by Gül in response to Q4, it can be assumed that, according to her, explanatory ideas come from direct observation. In the example related to the magnet practice, the students could discover which of the materials are pulled or not pulled by the magnet, but they cannot discover explanatory ideas, such as why some materials can be pulled by the magnet, while the others cannot. In this example it may not be clear what exactly Gül means about what the students discover. However, Gül clearly highlighted “the discovery of scientific theories” in her response to Q7 and she agreed with the idea that students can discover scientific theories by collecting sufficient data and their own observations. In addition, it seems that Gül emphasized the importance of prior knowledge and thoughts in an inquiry-based activity in terms of pedagogy, rather than epistemology because in her answers there were no ideas showing the importance of prior knowledge and thoughts to interpreting observational data.

The views of another participant (Ömer) regarding an observation from daily life are given below. His views were also coded as explanatory ideas coming from direct observation.

Imagine a child going to the seaside for fishing with his/her father for the first time. Think that the child observed that a fish could not move after a while it was put into the bucket without water. After this observation, the child discovers simply why fish cannot live out of water. (Ömer, open-ended questions/Q7)

Ömer assumes that explanatory ideas such as “why fish cannot live out of water” simply come from observations. According to him, when children observe that a fish cannot move if it is taken out of the water for a while, they discover why fish can (or must) live in water. However, while this observation may lead the child to make an inference that the fish can live in water but cannot live out of water, it is difficult to understand why fish cannot live out of water with this observation.

In their practical work plans, half of the participants again expressed the idea that students could explore scientific knowledge from observations made in their practical work.

Moreover, these participants believed that students could also explore the correlations between the observations and the ideas without talking about the ideas. For example, Berrak addressed the separation of mixtures as a topic in her practical work plan. Students were included directly in practical work, without explanations or talking about ideas such as what a mixture is and how various mixtures can be separated. The student groups were given various mixtures (such as sand, salt, and nickel powder) and asked to separate the mixtures by using materials such as a magnet, an ebonite rod, a beher glass, a funnel, a Bunsen burner, and distilled water. During the practical work, there was no guidance given to the students. Explanations regarding separations of mixtures were given by the teacher at the end of the practical work. The following is a section of the interview with Berrak about her practical work plan.

Researcher (R): In your practical work plan, are there any questions to students such as “Why do you think so?”

Berrak: No, there are not.

R: Why don’t you ask such questions?

Berrak: Because the students cannot know the reasons of a topic without explaining the theory of this topic.

R: Well, if so, why do you use this practical work?

Berrak: I use this practical work for the students to understand the topic of separation methods by themselves.

R: Can the students determine that which separation method will be used in which cases, on their own?

Berrak: Yes, they will.

R: How can they determine them through this practical work?

Berrak: They can determine by using their prior knowledge. This is a simple thing and in any case they can do.

R: What kind of prior knowledge the students should have?

Berrak: For example, the prior knowledge about dissolution and magnetism.

R: But what if the students do not have prior knowledge or their prior knowledge is incorrect?

Berrak: But, if I explain all the theory, they will expect to have everything handed to them on a silver platter.

R: What do you mean by “they will expect to have everything handed to them on a silver platter”? Do they find the theory by themselves through a practical work?

Berrak: Yes. Otherwise, it sounds [to] me like I’m going to do everything. It is not important whether students have prior knowledge or their prior knowledge is incorrect. If they failed during the practical work, they may realize that they don’t have enough subject matter knowledge. In this way, the subject will be learned better. I’m learning much better this way.

R: Then, is this your purpose of making this practical work? Namely, you want to ensure that students realize that they do not know the subject matter knowledge via this practical work?

Berrak: In fact, it was not my intention. I do not know…

According to Berrak, students’ prior knowledge, if any, about dissolution and magnetism and their observations are enough to discover the separation methods by themselves. Berrak's ideas such as “expecting to have everything handed to them on a silver platter” or “they realize that they do not have enough subject matter knowledge” were similar to those of other participants who used the practical work in their plans to provide learning by discovery for students. It was observed that these participants focused only on scientific content knowledge in their practical work plans. There was no clear relationship between what the students are expected to do with the practices and ideas. Also, there were no questions provided by the plans to guide students toward the relevant ideas, explanations, or theories during these practices.

Nazan also expected students to arrive at explanatory ideas from the connections between their observations and prior knowledge during practical work—without discussion of these ideas. In her practical work plan, she planned for students to learn Boyle's law. For this lesson, she had planned to pop kernels of corn in the classroom. She believed that students could come up with an idea related to Boyle's law from their own connections between observations of popping corn and prior knowledge about the physical behavior of gases. Part of the interview with Nazan is given below.

R: What is your purpose of practical work?

Nazan: My purpose is to help students to understand Boyle's law.

R: Do you expect that students can explore an explanation as to how corn kernels pop or what makes corns pop based on their observations?

Nazan: Yes, I do.

R: How can they do this with the practical work? I mean, how can they explore it?

Nazan: I am planning to ask them a question like “How can you explain how corn kernels pop when you consider the physical behavior of gases?” With this question, I make the students think of making connections between the event [popping of kernels] and pressure–volume relationship of gases.

R: Can you explain how corn kernels pop?

Nazan: Popcorn kernels obtain a variable amount of water in their endosperm. When a corn kernel is heated, the trapped water in the endosperm turns into steam, creating pressure inside the kernel. As the pressure builds, the casing eventually cracks, and the kernel explodes and pops.

R: Can we expect students to make such an explanation without learning whether they know how the structure of a corn kernel is?

Nazan: Yeah. It makes sense. In that case, I should tell the students that there is some water in corn kernels.

R: Ok. What is the relationship between popping a corn kernel and Boyle's law?

Nazan: According to Boyle's law, for a fixed amount of ideal gas kept at a fixed temperature, pressure and volume are inversely proportional. [She thinks for a few seconds] But, now it seems as if there is no relationship. … I think this practical work is not suitable for teaching Boyle's law.

Nazan took an opportunity to consider the relationship between practice and theory in her practical work plan through this interview. Her point of view on her practical work changed in a moment. She knew the explanations as to how corn kernels pop, and for Boyle's law. However, it seems that she had not considered whether there is a relationship between the popping corn and Boyle's law. She also had not considered what kind of prior knowledge students should have. Although knowledge about the structure of a corn kernel is an important factor in explaining how corn kernels pop, she had not included it.

After analysis, it was observed that only three participants were aware that it is important to consider students’ prior knowledge or conceptual framework and prior experience in terms of epistemological aspects of science such as theory-laden observation. The majority of the participants (n = 17) emphasized its importance as it related to pedagogical aspects such as “student readiness.” Table 3 shows categories and examples of participants’ responses about eliciting students’ prior knowledge or conceptual framework and prior experience before practical work.

Table 3 PCTs’ views about the importance of eliciting the students’ prior knowledge or conceptual framework and experience before practical work

Q9-Is it important to elicit students’ prior knowledge or conceptual framework and prior experience before practical work? Why?
Not important (n = 2)	Important as epistemological (n = 3)	Important as pedagogical (n = 17)
“No, it is not important because students can obtain knowledge and experience related to new subject through the practical work.” (Bilal)	“Yes, prior knowledge is very important because students think and decide how they research through their prior knowledge.” (Gülşen)	“Yes, because students can learn according to their level of readiness.” (Pelin)
“Not important because students do not have prior knowledge before learning a new subject.” (Selim)	“Yes, for example when a student faced with an anomalous situation such as the lack of expected color (in practical work) he or she can interpret why that is through his or her prior knowledge or experience.” (Orhan)	“Yes, because students may have some misconceptions about new subject. Thus, these misconceptions must be removed. Through inquiry-based learning these misconceptions can be eliminated.” (Tülay)

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To verify scientific theory

The second most common aim of practical work especially that based on experimentation and observation was verifying scientific theories. The participants (n = 12) with this aim thought that practical work functions as if independent from scientific theories. One response that reflects this kind of aim is given below.

If theoretical knowledge taught in lectures is put into practice in the laboratory, this theoretical knowledge is better learned. In this way, students will be provided with more effective learning. For example, when students observe the effect of acids or bases on the litmus paper, the topic of acids and bases becomes more understandable for them. (Selim, open ended questions/5).

According to Selim, theoretical knowledge is learned in the classroom and then this knowledge is consolidated by practical work in the laboratory. However, in science, there is no such order: i.e., first theory, then experiments, or vice versa. As in the example given by Selim, if practical work is used to verify acid and base theories explained earlier in the classroom, learners will only confirm the theories and not practice inquiry into acid and base theories.

According to Kaan's response, experiments are conducted to serve the understanding of theory in both science and science education. “The laboratory is the place, which is intended to practice and visualize theoretical knowledge provided in the classroom…a scientific experiment is also a practice of a scientific theory” (Kaan, open ended questions/8). Like Kaan, some other participants thought that the purpose of experiments in science and that in school science are the same. But, in reality, the purpose of experiments in professional science is different from that in school science. The main purpose of experiments in science is not providing a better understanding or verifying the theory to others (Kirschner, 1992). Instead, there is an interrelated and interactive relationship between experiment and theory; namely, scientific experiments help in forming scientific theories by giving feedback related to theoretical speculations, and scientific theories determine the kind of testing to be done experimentally and how to interpret data (Hodson, 1996). Therefore, experiments and observations in school science should not be used to verify scientific theories. If experiments and observations were treated as an important part of the formation of a theory, the epistemology of science would be reflected in a more appropriate way in science classrooms. Further examples from participants’ responses about this issue follow.

R: Can a student explain why and how an event or a phenomenon, for example a chemical reaction, occurs only based on his or her observations?

Sonay: Yes, he or she can explain it because the knowledge observed by the student is sufficient for an explanation. (from interview)

In the question above, although an event or a phenomenon is emphasized, according to Sonay, what is observed is “knowledge.” She thinks that before observations the student is given knowledge and this knowledge is confirmed through observations. But in science, an event and/or a phenomenon are observed, and then knowledge is obtained by the interpretation of observational data.

The common underlying reason for participants’ belief that practical work should be used to verify theories was the thought that knowledge learned in this way will stay in mind longer. For example.

The purpose of laboratory practices at school is to put theoretical knowledge into practice and is to ensure students understand the subject matter knowledge. Students observe an event and so it makes sense for them. Students’ interest and curiosity increase through practices. For example, when a solution prepared by students is shaken, it changes color. At that moment, the students understand that a redox reaction occurs. This practical work is interesting for them and the knowledge obtained by this way also stays in their mind for a long time. (Berrak, open ended questions/6)

… for a student, learning a topic in a visual way is always an effective learning. For example, if we say that a violent exothermic reaction occurs between Na [sodium] metal and water students can forget it. But if we show this reaction to students, it will create a more permanent learning for them. (Ferda, open ended questions/5)

Millar (1998) mentioned that there is a “memorable episode supply” function to practical tasks. That is, there is some evidence that our memories store not only ideas and rules but also whole episodes. Therefore, this function is an important element in defending the idea that practical work is useful for learning. However, he emphasized that the memorable episode supply function of a practical task can only be meaningful if students learn the topic alongside their interpretation of the event. The practical tasks are not useful if students learn the subject in a superficial way that exists as a complete event in the memory, absent of theory or background information (Millar, 1998). In the interviews, participants elaborated on what they meant by advocating that use of practical work helps students to keep the theory in mind longer. Participants thought that practical work would result in permanent learning by providing visuals to students, even without drawing their attention to the importance of interpreting events in the practical work. According to Ferda, whose views were given above, instead of telling students directly that a certain metal reacts vigorously or even explosively with water, the reaction is remembered longer after a practical alone because a violent reaction provides visuals.

More evidence for the aim “to verify scientific theory” came from the participants’ practical work plans. It was observed that nine practical work plans presented the content from theoretical to practical, without any questions to help students to connect theory and practice. For example, in Deniz's practical work plan, she aimed to teach the types of chemical reactions. Firstly, she gave a definition of chemical reaction, and examples of the types of chemical reactions. Then she asked students to make a practical application of each of these types of reactions. She gave a worksheet for each group. In these worksheets, what students should do for each type of reaction was described step-by-step. During the practices, the work plan did not include questions about why something was a redox or neutralization reaction. Although prior knowledge and explanations were given to students at the beginning of the practical work, they were not given any opportunity to establish a relationship between the prior knowledge and practices. Therefore, it can be said that the relationship between method and theory has been neglected. The reactions were carried out as if they were designed to confirm the explanations of the reactions.

To make scientific theories concrete and provide visual learning

Participants (n = 7) thought that practical work should be used to help students have a physical representation for scientific theories. In their interviews, some of the participants expressed that experiments in science make theories concrete. The use of practical work, especially experiments, both at schools and in science with this aim in mind is epistemologically problematic because science is concerned with theoretical concepts and the interrelated relationships between them. As Kirschner (1992, p. 281) noted, “theoretical concepts are abstract and should be considered and manipulated theoretically.” In chemistry, there are many concepts that must be understood through theory: the atom, molecule, nucleus, electron, proton, and chemical equilibrium. Experiments related to these concepts cannot make them concrete. Some of the participants’ statements about this problem are below.

… An experiment means to investigate any prediction about a topic using a variety of materials in a concrete way. (Sare, open ended questions/8)

The purpose of practical work is to learn by visualizing the topics which students [fail] to revive in their minds. For example, seeing a mix of acids and bases, catching the end point in the titration or seeing the formation of a crystal or precipitate facilitates learning. (Derya, open ended questions/5)

The titration example, which was given by Derya, is a very good example to clarify this epistemological problem. In titration, there are two concepts: “equivalence point” and “end point.” The equivalence point is the point in a titration where the amount of titrant added is enough to completely neutralize the analyte solution. The end point is the observable change during titration that signals that the amount of titrant added is chemically equivalent to the amount of analyte in the sample. In other words, while the equivalence point is a theoretical concept, the end point is an observable concept related to the concrete reality of this theoretical concept. Thus, observing the end point in a titration study, even several times, does not guarantee that students understand the equivalence point concept.

To develop students’ scientific process skills

Nearly a quarter of participants (n = 5) thought that practical work is used to develop students’ scientific process skills. However, the importance of context was not considered in the development and evaluation of these skills. They thought that there exists a direct relationship between skill development and the number of skill development practices. Participant responses that reflect this category are given below:

Observing, collecting data, conducting an experiment, etc., are scientific process skills. These skills should be developed through practical works. (Davut, open ended questions/10)

Scientific process skills should be developed by doing science… The more you practice, the more you develop the skills. (Gülşen, open ended questions/10)

Developing not only manual skills but also higher-level skills such as observing, measuring, predicting, and inferring is a very common goal of practical work (Wellington, 1998). However, this purpose does not reflect contemporary understanding about the epistemology of science; these skills are connected to the content and cannot be transferred from one context to another (Hodson, 1993, 1996; Wellington, 1998). Making multiple observations on the same subject can only develop observation skills in that subject. Therefore, it is a misconception that “the more you practice, the more you develop the skills” regardless of content or context.

None of the participants mentioned the importance of context or content in the development of the skills for the following case:

A teacher wants to develop all of the scientific process skills of students in the first month of the academic year. Firstly, she creates a list of all the scientific process skills to be developed. Then, she plans a variety of practical work by which their skills can be developed in the first month of the academic year. In this way, she thinks that she may adapt the curriculum to meet the needs of students in terms of the scientific process skills.

(a) What do you think about the teaching approach of this teacher?

(b) How should the scientific process skills be developed?

Examples of responses to these questions are given below.

… in my opinion, it is impossible to develop all these skills in a short time like a month. Practices that develop these skills should continue throughout the academic year and the outcomes of the practices should be followed. (Serpil)

The teacher seems not to care too much about developing these skills. A month is too short for these skills to develop. (Selim)

All participants criticized the teacher's teaching approach based on pedagogical understanding only. For example, some of them, like Serpil and Selim, thought that scientific process skills could not be developed in just a month or so. Others found this approach faulty because the teacher does not follow up on the development of these skills after a month. However, there was no epistemologically-based criticism, such as “demonstrating skills for a specific topic does not mean that these skills can be demonstrated for other topics.”

To provide learning about the nature of science

Only one of the participants was interested in using practical work to improve students’ understanding of the nature of science. She thought that if students participated in an inquiry-based practical work, they could learn something about science implicitly. However, this participant was also in favor of using the practical work to “verify the scientific theories,” which has been noted as an epistemologically problematic aim in this study.

Conclusions and implications

Although practical work has always been an important and indispensable component of science education, it is questionable whether it is used effectively in school science. Perhaps it can be said that practical work is effective when the aim of the practical work is reached. But does it still hold that the practical work is effective or meaningful if the aim itself is problematic? The purpose of this study was to explore epistemological problems underlying pre-service chemistry teachers’ aims for their use of practical work in the classroom. To reveal the epistemological problems, participants’ views about science teaching methods (e.g. discovery learning, inquiry-based learning) and practical work were investigated, as were their practical work lesson plans. It was found that almost all of the participants had more than one aim in their practical work; furthermore, there were several epistemological problems underlying some of these aims. The epistemologically problematic aims were categorized according to the frequency of occurrence as follows: (1) to provide discovery learning, (2) to verify scientific theory, (3) to make scientific theories concrete and provide visual learning, and (4) to develop students’ scientific process skills.

The most common motive for using practical work was related to the idea that practical work would provide learning by discovery. Some of the participants thought that the students would be able to directly discover explanatory ideas from observational data obtained in the practical work in which they were involved. This finding shows that these participants may also have naïve inductivist views. They thought that explanatory ideas would emerge from students’ own connections between their observations and prior knowledge. Although this expectation seems to be an informed view in terms of theory-ladenness, the participants did not evaluate the connections between students’ observations and prior knowledge in terms of the epistemology of science. Tsai (1998) summarizes eight assertions of the constructivist epistemology that provide a potential interplay between the philosophy of science and students’ learning psychology in science. One of the assertions is related to the interplay between “observations are theory-laden” (constructivist philosophy of science) and “students’ existing conceptions play an important role for new knowledge acquisition” (students’ learning psychology in science). Many participants in this study did not consider this interplay. In addition, the participants thought that it would not qualify as a discovery if prior knowledge was given to the students before practical work; contrarily, they also thought that students should discover new knowledge by their own prior knowledge. Abrahams and Millar (2008) observed some practical work in various high school science courses in England and interviewed both teachers and students about practical work. At the end of the interviews, they made some conclusions about the effectiveness of the practical work. For example, they found that while the students were able to make observations requested by their teachers, they could not use the ideas and explanations they wanted to teach. Based on these findings, they concluded that there are few cognitive elements that make the connection between the observations and explanations be taught in practical work, and that the tasks given to students do not include clear strategies to help them establish these connections. In the present study, it was also revealed that some participants gave prior knowledge and explanations to students, but they did not give opportunities to use and connect these knowledge and explanations with the observations in practical work plans, and they neglected the relation among method–observations–theory. From this point of view, during the practical work design in chemistry education and also generally in science education, it can be said that there is a need for clear strategies that will enable the students to relate between the explanations and observations in the tasks given to them. For example, strategies such as POE (predict–observe–explain) can be important in practical work.

The second most common reason for using practical work was to verify scientific theories. Other studies have also found that this reason is very common among teachers (e.g.Kerr, 1963; Abraham and Saglam, 2010; Lewthwaite, 2014). Participants with this aim assume that knowledge learned in this way will stay in mind longer. It can be said that the participants internalized the popular Chinese proverb: “I hear and I forget, I see and I remember, I do and I understand,” which was also adopted by some national curriculum projects in the 1970s and ’80s. Again, it is important to emphasize that the theory or principle that is intended to be taught by a practical work is not independent from that practical work. Therefore it is epistemologically problematic to work as if there was an order of theory and practical work. Moreover, it is believed that the practical work which was carried out to verify a theory is ineffective because it is based on tasks that follow a recipe or cookbook. In such practical work, students are engaged in activities based on hands on rather than mental processes related to theory and they follow the steps to be followed mechanically without thinking in depth about the subject to be learned (Gunstone, 1991; Hodson 1996; Chinn and Malhotra 2002; Clough and Olson 2004; Millar 2010). According to Gitomer and Duschl (1997), science teachers generally give importance to a number of activities and practical tasks, not to conceptual structures and scientific thinking when they think of their teaching. In the PCTs’ practical work plans, the course of action was also forefront. If pre-service chemistry and science teachers have gained understandings of the epistemology of science and they are shown how to use them in practical work, they may be highlight scientific thinking.

Making scientific theories concrete and providing visual learning was another reason given for using practical work, especially experiments. The participants perceived experiments as visual representations of scientific theories. In science, visual representations such as models (e.g., atom and molecule models), photographs, and diagrams are used to interact with and represent complex phenomena, not observable in other ways (Evagorou et al., 2015). But the same thing may not be said for experiments, which are part of the process for knowledge production in science. So, experiments can provide visualizations for scientific methods and scientific reasoning, but not scientific theories. Science teachers and pre-service teachers need to distinguish this difference. Another aim for using practical work is to develop students’ scientific process skills, such as observing, classifying, and predicting. At first glance, there seems to be no problem with this aim. However, it can be said that this aim is problematic in terms of theory-leadenness. None of the participants mentioned the importance of context or content in the development of these skills.

It is believed that the awareness of epistemological problems uncovered in this study will guide curriculum developers and chemistry teachers to better design laboratory studies in chemistry education. As a result of the reviews of many research studies and essays by Hofstein and Lunetta (Hofstein and Lunetta, 1982; Hofstein and Lunetta, 2004), it was concluded that there is a tradition of conducting experiments without clear purposes and goals. They revealed a notable mismatch between teachers’ goals for learning in the science laboratory and those that were early defined by curriculum developers and the science education community.

Although the sources of the epistemological problems underlying the participants’ aims were not investigated in this study, some ideas about the sources could be concluded. One source of problems may be the participants’ ignorance about the theory-laden nature of scientific knowledge and processes. Theory-ladenness is, in brief, the effect of prior knowledge or theories on how observations are made (Osborne and Dillon, 2010), the way in which data are gathered and interpreted, and which method is preferred (Hodson, 1998; Chinn and Malhotra, 2002). If the participants were informed about theory-ladenness, they could take several steps: (1) encourage students to interpret the phenomena in the practical work by providing them with prior knowledge; (2) use practical work as an important part of the development of scientific theory, not as a tool for verifying it; (3) understand and explain that practical work does not have the property of concretizing scientific theories; and (4) develop and evaluate the science process skills used in the practical work in the subject taught. Science educators should illustrate to science teachers and pre-service teachers ways to establish links between theory-ladenness and the aims of using practical work. The findings in this study about pre-service chemistry teachers’ aims and the discussions of why they are epistemologically problematic may be helpful to establish these kinds of links.

Another source of epistemological problems could be related to the inability to distinguish between doing science and learning to do science. As stated by Kirschner (1992), the “content of the pedagogical learning experience is believed to be the same as the syntactic structure of the discipline examined” (p. 273). As is evident in this study, pre-service teachers suppose that the aims of experiments in both science and school science are the same. To avoid such a mistake, chemistry teachers and pre-service chemistry teachers need to think about why an experiment is used and how it is done from both epistemological and pedagogical perspectives. Providing students opportunities to link the relevant theory with data collected through their practical work creates epistemologically sound practical work. What needs to be considered pedagogically when doing practical work is how these kinds of opportunities can be provided to students. For example, argumentation-based teaching is a strong pedagogical way to provide such opportunities to students because it provides justification of knowledge claims rather than asking students to pseudo-discover them.

In relation to the assumption that doing science is identical with learning to do science, another conclusion of this study is about learning and teaching of the “nature of science.” There have been claims that the “implicit approach” is not an effective way to teach the nature of science. According to Khishfe and Abd-El-Khalick (2002), one reason for the ineffectiveness of the implicit approach in enhancing students’ views about the nature of science is related to the underlying assumption that “students would automatically develop better nature of science conceptions as a by-product of engagement in science-based inquiry activities or science process skills instruction” (p. 553). However, the main reason for the ineffectiveness of the implicit approach can be discussed in terms of the results of this study. When the epistemological problems shown in this study are not eliminated as part of the lesson planning for inquiry-based, discovery-based, or process-oriented practical work, the implicit approach is already destined to be ineffective in teaching the epistemology of science or, more generally, the nature of science. Moreover, these problems may even cause misunderstandings about the nature of science. For example, in this study, it was observed that nine practical work plans presented the content by starting with theory and moving to practice. There were no questions that stimulated students’ thinking about the connections between theory and practice. Therefore, it can be said that the relationship between method, data, and theory is neglected in these kinds of practical work plans. So, what can be expected from students who were engaged in this kind of practical work to learn implicitly about the nature of science? Students are likely to think that there is no interactive relationship between method, data, and theory. They may think, “These are independent of each other. First the theory is revealed and then this theory is verified through an experiment, but I do not know where this experiment comes from.” In this case, it is wrong to think that the implicit approach is inadequate as a result of having such misconceptions about the epistemology of science. In this study, only one participant aimed to use inquiry-based practical work for teaching the nature of science. However, her practical work plan was designed to “verify the scientific theory.” Therefore it is necessary to take into account the extent to which the practical work itself is compatible with the real science when evaluating the effectiveness of teaching strategies and individual lesson plans. Students in schools need opportunities to reflect upon carefully planned and structured inquiry experiences to achieve epistemological insights. (Abd-El-Khalick and Lederman 2000; Khishfe and Abd-El-Khalick, 2002; Bell and et al., 2003; Peters and Kitsantas, 2010; Yacoubian and BouJaoude, 2010; Abd-El-Khalick, 2013).

Generally science teacher education programs and especially chemistry education programs where laboratory work is intense, the difference between the “epistemology of science” and the “pedagogy of science education” should be explicitly discussed and emphasized. For example, in science methods courses, the difference between them should be explained through some practical work cases. In these practical work cases, the purposes of the practical work should be explained explicitly in terms of both epistemological and pedagogical perspectives. For example, in Nazan's practical work plan (given in the Results section of this study), she expected that students could come up with explanatory ideas about how corn kernels pop by forming their own connections between observations of popping corn and prior knowledge about the physical behavior of gases, without talking about these ideas. When Nazan got a chance to think about the purpose of her practical work, she understood that her practical work plan was not suitable to teach Boyle's law.

In order for teachers to reflect science more accurately, the explanations in textbooks and curriculums should guide them on how to conduct practical work. Unfortunately, in most cases, some explanations about science are given very generally in the first chapter of the science teaching books under the titles “nature of science” or “what is science?” without referring the activities or practical work in these books. If more detailed explanations in light of the epistemology of science are included in the practical work procedure, the teacher can better understand how to conduct practical work. The epistemological problems about practical work determined in this study will help instructors to better understand why practical work is currently ineffective in school science, and to design more authentic scientific inquiry practices for future students.

Limitations of the study

The first limitation inherent to this study is related to the fact that findings are limited to the PCTs enrolled in the course. On the other hand, the purpose of this case study is not to generalize the findings. There are some critics in terms of epistemology in the science education literature about science teaching methods and practical work which is used for implementing these teaching methods. In this study, we tried to reveal these epistemological problems through a qualitative research. The second limitation might be related to reaching conclusions about the epistemological problems from PCTs’ practical work plans in the not real classroom environment. However, these practical work plans were not the only data source of the study to explore the epistemological problems; there were also other data sources in this study.

Authors’ note

This study is a part of the first author's doctoral dissertation.

Conflicts of interest

There are no conflicts to declare.

Appendices

Appendix 1

1-What is scientific inquiry?

2-How should teaching of science as inquiry or inquiry-based science teaching work?

3-Imagine a chemistry teacher uses inquiry for a teaching method in his/her course. For what purpose might he or she have preferred this method?

4-What do you think about discovery learning in science education? What is the purpose of discovery learning? Please explain by giving an example.

5-What are the goals of practical work (any science teaching and learning activity in which the students working individually or in small groups observe and/or manipulate the objects or materials they are studying) in schools?

6-What should be done in laboratory studies in schools? (What types of activities should be performed?) Can you explain by giving examples?

7-Can students discover a scientific theory by just observing the process? For example, can students discover explanations about dissolution only by observing soluble, insoluble, and poorly soluble substances in water and by collecting enough data on them?

8-Is there any difference between scientists’ research practices and students’ schools practices in terms of the activities undertaken? Can you explain by example?

9-Students can be involved in some practical work, such as observing, collecting data, and conducting an experiment when they learn a new subject. Is it important to elicit students’ prior knowledge or conceptual framework and prior experience before practical work? Why?

10-What are the scientific process skills in an inquiry-based science lesson? Please explain how to improve these skills with examples.

11-Do you think that the students can learn what science is and how to do science in their science courses and laboratory practices? Why? Please consider what you learned about science in your own student years.

Appendix 2

A group of students carry out a practical work in their school laboratory. All instructions in the practical work are given to the students step by step through a lab sheet as shown below.

1-Set up a length of visking tubing and fill it with a mixture of starch and glucose solutions. Suspend it in a beher glass of water for a time as shown in the figure.

2-Periodically test the water with Benedict's solution and with iodine solution for the presence of starch and glucose.

3-Record your observations in the table given below.

Time	Benedict solution	Iodine solution

1-Did students do an experiment in this practical work?

Yes, because .......................................

No, because .........................................

2-What should be the purpose of such a practical work?

................................................................................................

3-With this practical work, students think that they obtain evidence about how digestion happens in the human body. So can we say that this practical work is useful or not? Please explain your answer.

....................................................................................................................................................................................................................................

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