Starting the Educational Reform from the Beginning: Croatian Pre-Service Chemistry Teachers’ Level of Pedagogical Content Knowledge on Particle Theory

Abstract

Changes in the educational system need strong support from and connection to teachers. For this, knowledge about teachers is needed. A key factor in changing the chemistry classroom reality are teachers—in-service and pre-service. Chemistry Education Research is a new domain in Croatia. Since the transfer of the data from various undertaken studies on teachers’ knowledge is not easy based on differences in educational systems, research in the Croatian context is needed. Particle Theory is one of the main topics and the basis of chemistry teaching and learning. This study is based on open-ended questions following the frame of pedagogical content knowledge (PCK) and Big Ideas about Particle Theory by Loughran. Data analysis follows the pattern of graduating the PCK of the participants at the novice, intermediate or advanced level. The results show that pre-service chemistry teachers’ PCK is either novice or intermediate on the national level, while the results for particular universities show some differences in chemistry pre-service teachers’ PCK. Thus, the study can be an excellent starting point for chemistry teacher educators in university for further development of pre-service teachers’ PCK.

1. Introduction

Many political and structural changes in Croatia over the past 30 years are noticeable in the educational system as well. In the last few years, the voice of a need for a new educational reform, which is strongly oriented to the Western world, has become louder and louder, and the new improved curriculum has been in use since 2019 in the seventh grade of primary school (ages 12–13), first grade of grammar school (ages 14–15) and at all levels since autumn 2021. In the Croatian educational system, primary school is from first to eight grade (ages 6–14), and secondary school is for students aged 15–19 (first to fourth grade) and can be grammar school or vocational school. Before this change, chemistry was taught based on the curriculums made at the beginning of the 1990s (Croatia before that time was a part of Yugoslavia). Chemistry is taught in a spiral curriculum with the extension of the knowledge gained in primary school (grades 1 to 8 and ages 6 to 14), as well as the knowledge gained in prior years of grammar school/high school (grades 9–12) in the Croatian system, again grades 1–4 and age 15–19. Focus on high school chemistry is a connection and an interweaving of the content; thus, the curriculum is less focused on learning by heart and more on making links between the content and, e.g., social and environmental issues. The content, as suggested by the National Chemistry Curriculum [1] and made by the Ministry of Science and Education, is divided into three basic chemistry

Concepts: (i) matter, (ii) chemical process and changes and (iii) energy. The goals of Scientific Literacy are incorporated into all three concepts. The inquiry-based learning should be seen as the main practice in chemistry lessons, and experiments are the foundation for gaining new knowledge [2]. However, this approach is new in Croatian chemistry education and started at all school levels in the beginning of the 2021/2022 school year. Preparation for this approach started in the 2019/2020 school year with a gradual introduction of the new curriculum. There were massive open online courses and workshops offered for teachers throughout the year, however, they were not obligatory.

Teachers, as the binding members of the educational chain, play a crucial role in the success of different educational reforms and in changing the classroom reality [3]. The curriculum changes, as well as more student-centered, constructivist-oriented and modern ways of teaching, need not to be only in Croatia but in other countries of the East Balkan area. Therefore, this study is applicable to other countries, especially the Slavic languages. Other than a translation of the questionaries, there is no need for greater language intervention, and the analysis of the results can easily be made among researchers from different countries. This is also a good starting point for the comparison of Western pre-service Chemistry teachers’ level of PCK with the Croatian one.

Since this was the first big curriculum change in the past thirty years in Croatia, especially in the grammar school curriculum, it was not enthusiastically welcomed by all teachers. Some of the teachers were not comfortable with the expected change in the curriculum, as well as with the new approach to teaching chemistry. Thus, to successfully implement such an educational reform, the questions should arise: On what ground is the reform based? What knowledge about the implementation of the reform do (future) chemistry teachers have?

2. Theoretical Background

Teachers’ knowledge of the content and their knowledge of pedagogy create an amalgam that was described in 1986 by Shulman [4] as pedagogical content knowledge (PCK). PCK is knowledge of how to teach particular content in a particular way, developed over time and through experience [5]. There are four major sources of PCK development by Grossman [6]: (i) disciplinary education (subject matter knowledge), (ii) observation of classes (pre-service teachers’ knowledge of in-service teachers’ difficulties), (iii) classroom teaching experiences (pre-service teachers’ knowledge of topic-specific activities) and (iv) specific courses or workshops during teacher education programs (to affect PCK).

There are different concepts of PCK. One often used in the science education community is the approach by Loughran and colleagues [7]. For the best representation and portrayal of PCK, they defined two tools: Content Representation (CoRe) and Pedagogical and Professional–experience Repertoires (PaP-eR). They not only help in capturing teachers’ PCK but serve as well as a portrait of this knowledge to others [7]. While CoRe stands for a holistic overview of PCK, PaP-eR is more of narrative nature to help illustrate and better understand that specific PCK. CoRe and PaP-eR together comprise a Resource Folio (RF) for a specific content area such as Particle Theory. Resource Folio unites teachers’ collective understandings (CoRe) and individual illustrations of a specific practice (PaP-eR). It is trying to close a theory–practice gap [5] by creating ways to better understand and value teachers’ knowledge, skills and abilities. This combination of content representation and illustration of teachers’ practice can also be a starting point for teachers’, both in-service as well as pre-service, personal and professional development by embracing PCK in their practice.

As mentioned by Lehane [8], CoRe alone has been used by more researchers than combined with PaP-eR. As Nilsson [9] (p. 113) summarized, CoRe is “…a detailed description for teaching a science topic based on a recognition of the big ideas for that topic mapped against pedagogic prompts including (i) what students have to learn about each big idea, (ii) why the students need to know this idea, (iii) students’ possible difficulties with learning the concept and (iv) how this concept fits in with knowledge the teacher holds about that content…”. CoRe itself is not PCK because of some of limitations, such as being information propositional in nature and limitations of providing insight into teachers’ experience of practice. Therefore, a “window into PCK” was developed—PaP-eR—which unites “…teachers’ practice, thinking and understanding of teaching particular content in particular ways to particular times…” [5] (p. 19).

A CoRe is formed as a matrix and its aspects are (i) Big Idea on the horizontal axis (this refers to a scientific idea important for the development of the understanding of the topic) and (ii) “unpacking” the Big Idea on the vertical axes with questions. The term “Big Ideas” [10] was conducted and stands for interrelated concepts, rules and methods. It can be helpful in the determination of the aim and core concepts of the chemistry curriculum. Development of the idea of Big Ideas is given in de Jong and Talanquer [11] and, as stated by Sevian and Talanquer [12], these crosscutting concepts are critical in the understanding and practice of chemistry.

A very important aspect of PCK [7] is a good familiarity with teaching procedures. When, how and why to use some teaching procedure, and the ability to change and adapt to given circumstances, distinguish teachers and their teaching. Teachers’ approaches to activities, procedures and strategies for teaching a specific subject should be based on their observations and evaluations (formal or informal) of the students.

Pre-service teachers tend to have some difficulties with the PCK due to their lack of expertise. Many pre-service teachers, as indicated in research on science education, have a lack of knowledge of deep conceptual understandings of their subject matter (e.g., [13]). CoRe is a great deal of help in pre-service teachers’ education [14] in understanding PCK and the development of teaching particular areas. Although Hume and Berry [15] show that there can be difficulties due to lack of experience, they can easily be overcome with appropriate scaffolding and with a little help from colleagues. CoRe can be a useful tool for pre-service teachers learning and planning lessons, e.g., in primary school [16]. As given in Lehane [8], there is research about the application and usage of CoRe, such as turning pre-service teachers’ scripts for learning into CoRe format [17]; shifting from content-focused teaching to more pedagogically reasoned approaches [18]; and potential development of PCK by developing CoRe along with self-assessment and formative interactions with experienced teacher [19], as well as going beyond the traditional range of “tips and tricks” about how to teach [5].

Schultz et al. [20] adapted tools for determining PCK and used them on tertiary educators, and it resulted in representing significant topic-specific professional knowledge of tertiary practitioners. Williams and Lockey [14] indicate research about pre-service pedagogical approaches to help them lay down a foundation for their PCK development. A study by Van Driel et al. [21] shows the development of pre-service teachers’ PCK with a special focus on shifting from the macro to the micro level. Integrating pre-service teachers’ PCK into the teaching process based on the comprehension of scientific, pedagogical and didactic aspects is the focus of Sæleset and Friedrichsen’s [22] research.

Research on chemistry teachers’ PCK in Croatia is still very rare. Research on the understanding of chemical bonding by participants (students, pre- and in-service teachers) at all levels of the chemical education system in Croatia has been undertaken by Vladusic, Bucat and Ozic [23]. This study shows that at all levels of education, the existence of alternative conceptions was noted. Furthermore, the authors discussed that teachers’ PCK cannot be based on an inadequate level of content knowledge. In the study on pre-service teachers’ understanding of scientific words and representations and everyday words used in chemistry teaching [24], considerable differences in the extent of understanding from word to word and symbol to the symbol are indicated. Until the point of writing this paper, these are the only studies about PCK in chemistry education conducted in Croatia. There is no research on pedagogical content knowledge about Particle Theory, however.

3. Research Questions

Research on both in-service and pre-service teachers’ PCK is very important, yet insufficiently explored in Croatia in the field of chemistry education research. One of the major concepts in chemistry education is Particle Theory. The need is there since new educational reforms just started. Thus, new teachers must be prepared for the new educational system. To support them, in the sense of an initial diagnosis, this study is focused on closing this gap, and thus answering the following research question:

RQ 1: Which level of pedagogical content knowledge, with a special focus on Particle Theory, do Croatian chemistry pre-service teachers hold at the beginning of their university teacher training?

RQ 2: Are there any differences in the level of pedagogical content knowledge among Croatian chemistry pre-service teachers due to their university? If so, which?

4. Materials and Methods

4.1. Sample

To answer the named research questions, fifty pre-service chemistry teachers from three different Croatian universities participated in the study (University of Osijek, University of Split and University of Zagreb). Only in these three universities in Croatia are teacher education programs for chemistry offered; thus, the sample is to be described as representative, since all future chemistry teachers from one generation voluntarily participated in the study (51 chemistry pre-service teachers). Surprisingly, at first glance, all of the participants were female in the age range of 21–26 (M = 21.8). No male pre-service teachers were studied in this generation. Being a teacher is traditionally regarded as a female occupation in Croatia. They were in their first year of master’s study or fourth year of integrated study and just about to start with pedagogical courses such as education sciences, psychology and pedagogy, as well as chemistry education courses. All of the participants attended school in Croatia, and thus are familiar with the Croatian educational system. All of them have a final exam at the end of grammar school (Matura). In the meaning of diagnostics, the time point for data collection was after starting with general education courses but before the start of chemistry education courses. Thus, pre-service teachers’ PCK is diagnosed and can serve as a basis for planning chemistry education seminars and lecturers.

The study was conducted in the fall of 2017; thus, just before the educational reform started. Following this, the participants of the study did not experience any influence of the new educational reform as students or as future teachers.

4.2. Instrument

The participants were instructed to fill out the questionaries, with an assumption that they teach in the 1st year of grammar school (students aged 14–15 after finishing eight years of primary school, which is the same for all students). The instrument was based on the Content Representation (CoRe) of Particle Theory made by Loughran et al. [7]. There were seven Big Ideas about Particle Theory [7] (pp. 5–8):

(1)

The concept of a model is used to explain the things we observe.

(2)

There are different kinds of particles that, when joined, are different again. There are different “smallest bits“.

(3)

There is conservation of matter. Particles do not disappear or get created, rather, their arrangement change.

(4)

Matter is made up of small bits called particles.

(5)

There is empty space between particles.

(6)

Particles are moving (their speed is changed by temperature) and appear in certain arrangements.

(7)

Particles of different substances are different from one another.

Following the CoRes for each named Big Idea (BI), eight questions were asked:

• What do you intend the students to learn about this idea?
• Why it is important for students to know this?
• What else might you know about this idea (and you do not intend for students to know yet)?
• What difficulties/limitations connected with teaching this idea can appear?
• What knowledge about students’ thinking can influences your teaching of this idea?
• Which other factors can influence your teaching of this idea?
• Which teaching procedures will you use for teaching this idea and why?
• What specific ways of ascertaining students’ understanding or confusion around this idea will you use?

Pre-service teachers were given the Croatian translation of Loughran’s Big Ideas and questions. The essence of the questions is preserved, and the translation was validated by translating the Big Ideas and questions back into English. Data collection was carried out by the course holders of the chemistry teacher training course at the three universities, while processing and reporting were performed by the researcher. Questionaries were not mandatory, and filling them did not in any way influence the success of finishing the chemistry training course.

4.3. Data Analysis

The data analysis is based on qualitative content analysis [25]. The aim was to develop an evaluation pattern to characterize the existing knowledge of chemistry pre-service teachers. Using a deductive approach, the categories were built. For this first step, three categories were made based on the level of knowledge: novice, intermediate and advanced [26]. This was conducted for each of the seven above-named Big Ideas and the eight named questions. Before the full analysis of the questionaries, the evaluation pattern was adapted to the Croatian system. A revision of all three university syllabuses and related literature [27,28,29,30] for educational courses was made. Thus, a matrix was formed for each of the Big Ideas, with each question’s answers being scored as a novice, intermediate or advanced level of pedagogical content knowledge. Evaluation patterns for all seven Big Ideas were compared for each of the eight questions and for each of the levels and convergence if needed. The novice level of knowledge is the lowest level of knowledge that a pre-service teacher could poses, it is the general knowledge about teaching and learning and it is the anticipated knowledge after some pedagogical courses. An intermediate level of knowledge is basic knowledge for an average pre-service teacher, and they are expected to achieve this level after starting with science education courses but before having school practice. The highest level of PCK is the advanced pre-service teacher PCK, and it is the expected level after finishing both pedagogical and science education courses and the school’s internship. A short description of the three levels is presented in

Table 1. Levels of PCK and description for each question.

Question	Novice	Intermediate	Advanced
1.	Particle structure of matter; particle difference and their properties; particles cannot (dis)appear; particle motion; the idea of particles as little balls.	Visualization of chemical reactions; describing the observed changes (macroscopic level) on a particle level; properties of matter depend on the particles; creation of the new substances by reaction; nature of the particles; law of mass conservation; movement of the particles (under influence of various factors); properties of the substances are the result of the particles they are made of.	To show the microscopic level of chemical reactions (visualization of something abstract); there are different particles which can react due to their interparticle interactions; particle interactions; the diversity of the particles can be explained by the periodicity of the properties; redistribution of the particles; energy changes during the reactions; predicting the reaction.
2.	Understanding of structure matter and the properties; essence/basic concept of chemistry (no further information); lack of awareness of the importance of particles in chemistry (shown by the pre-service teachers).	Understanding of chemical reactions, explanation and visualization of them, especially on the particle level; chemical reactions are the result of different properties and interactions of the particles; particles are an important part of chemistry.	A deeper comprehension of chemistry (i.e., background of the chemical reactions); for the understanding of further chemistry topics; logical understanding of chemical changes (on particle level); development of logical thinking; energy changes during reactions; predicting the reaction.
3.	Subatomic structure; periodicity of properties (no further explanations); historical development of the atom; nothing special/many things/most of the academic education.	Chemical bonding (ionic bond, redox reactions); redistribution of particles; particle interactions; properties of matter due to the particles; law of mass/energy conservation; particle distribution; kinetics of the chemical reactions and factors affecting it (i.e., temperature); different particle size.	More complicated models of matter (VSEPR, conformations and complex compounds); quantum chemistry (sub-particles such as quarks); reaction mechanisms; parts of kinetics (i.e., collision theory), parts of thermochemistry (thermodynamic functions and ideal gas equation); electronic configuration.
4.	The abstractness of the concept; lack of prior knowledge connected with particle matter; lack of interest; there are no (difficulties/limitations).	Insufficiency of students’ knowledge (especially on particle level); misconceptions about particles and their interactions; harder visual perception; no connection between macroscopic and microscopic level; not knowing the terminology.	Cognitive abilities of the students; teachers’ insufficiency of knowledge and/or understanding; classroom atmosphere and/or discipline; problems of visualization and expression at the particle level; lack of teaching aids; teaching materials not adapted to the students (age, abilities or prior knowledge); spatial perception.
5.	Prior knowledge from Primary School or Science subjects; prior knowledge about the structure and properties of matter; lack of terminology; there are no (difficulties/limitations); other knowledge has no effect on teaching.	Knowledge about particle matter; lack of prior knowledge and misinterpretation of the terminology; previous encounters with a particle level and presentation; knowing the factors that influence the rate of reaction; interpretation of visual/graphic representations.	Misconceptions about particle nature of the matter in chemistry and prior knowledge about particle matter; not connecting the properties of substances with their structure; misunderstanding of the particle nature of matter; inexperience of particle representation (both from teachers and students); non-scientific sources of information; learning in advance.
6.	Students’ interest in the subject; prior knowledge of particle matter; misunderstanding of chemical terms; there are no difficulties/limitations.	Lack of prior knowledge needed to understand the concept; misconceptions about particle matter, interactions and reactions; visualization possibilities on a particle level; teaching procedures (not suitable for teaching these Big Ideas); class structure (students from different primary schools with different levels of knowledge).	Classroom management (atmosphere and discipline); teaching approach (creativity of the teacher, preparation of the teacher for the lesson, (mis)understanding of the concept by the teacher and teacher’s ability to bring the subject closer to the students); lack of ICT and teaching aids; external factors (media, parents and prior knowledge); cognitive abilities of the students.
7.	Frontal teaching; lectures (with no experiments; one-way conversation); text work (not guided or programmed).	Using demonstrations (experiments; guided experiment); taking notes, drawings; lectures with examples; use of multimedia (Power Point).	POE (predict, observe and explain); heuristic lectures; programmed teaching with textual materials; class and panel discussion; encouraging students to talk about the topic; using models; drawings on the particle level; linking activities; use of simulations/animations of reactions.
8.	Examination (oral or written); homework (without the specifications about the tasks in it); ask them: Is this clear? Do you have any questions?	Quiz; worksheets; discussion; particle representation recognition tasks; examples on the particle level in which students describe or connect the macroscopic and microscopic level.	Drawing of the particle level; students’ explanations to each other; problem task of concept application (i.e., representation of the particle level or connecting the experimental observations with the particle level); independent students’ performance on the experiments followed by their explanation and presentation of the results.

. The answers for some of the questions (for example, 4 and 6–8) can be aggregated among the Big Ideas, while for others, the answers provided in Table 1 are the most frequent ones and/or aggregated answers. A much more detailed table is made for each of the Big Ideas, with a greater span of answers for each of the levels. The fuller rubric is provided on request.

Questionaries were analyzed due to the evaluation pattern of each participant, determining the level of pedagogical content knowledge. The results were calculated on the national level and at the university level, and a comparison was made. The analysis was conducted by two independent chemistry education researchers. The rating was compared and, in the case of disagreement, a search for inter-subjective agreement was carried out [31]. In 90% of the answers, both evaluators gave the same rating.

5. Results

The collected data are analyzed in terms of three levels: novice (yellow color), intermediate (blue color) and advanced (green color) pedagogical content knowledge (see Table 1). The results are analyzed for the whole generation of pre-service teachers from all three Croatian universities to determine the level of the pre-service teachers’ knowledge about Particle Theory (RQ1), as well as separately for each of the three universities to distinguish differences (RQ2).

The Croatian chemistry pre-service teachers’ level of pedagogical content knowledge focusing on Particle Theory is presented in Figure 1. Each of the diagrams focusses on one Big Idea by Loughran et al. [7], as named before.

As can be seen in Figure 1, the level of pedagogical content knowledge is rather heterogenic and depends on the (i) Big Idea (BI) and (ii) type of question. Starting from the diagrams, an all-in-one overview cannot be drawn. In general, Croatian chemistry pre-service teachers’ pedagogical content knowledge of Particle Theory is rather heterogeneous with the dominance of the novice level represented by the yellow color (Figure 1), followed by the intermediate level of knowledge (blue color). The advanced level (green color) is the least represented one.

Comparing the data for all BIs, the advanced level of knowledge is the most represented one for the first Big Idea (BI1) about the usage of the particle model in the explanation of the observation (i.e., for q7 “…Experiment of dissolving the salt (copper(II) sulfate pentahydrate), class discussion, making observations, connecting the macroscopic view with the microscopic one (particle view)…”). This is also true for Big Idea 4 about the particle structure of matter. Big Idea 7, about the difference of particles, is in general at the novice level of PCK. Pedagogical content knowledge about concepts of particle properties after reaction (BI2 and BI3), particle interactions (BI5) and movement (BI6) presented rather homogenously between the novice and intermediate levels, with some participants in the advanced level. There is only very little knowledge shown in the advanced level for BI4 and BI5 about students’ thinking that can influence the teaching of certain Big Ideas. The most advanced level can be seen for BI1.

The intention (q1) and importance (q2) of learning these Big Ideas are for all the Big Ideas mostly at an intermediate level. Thus, the participants’ knowledge of the curriculum seems to be on a higher level than, for example, their knowledge of learners and science teaching, questioned in questions 4 and 5, and about the difficulties and limitations of teaching the idea, and the influence on teaching the mentioned Big Ideas, as in question 6. The level of knowledge for these questions is predominantly novice. The knowledge about the importance of learning the named Big Ideas (q2) is mostly on the intermediate level for all Big Ideas. Novice and advanced levels are shown in approximately the same ratio for that question. The most advanced level of knowledge about the importance of learning is shown for BI4:“…It is important because the particle level is important to understand the changes that we see (macroscopic level)…; “…It is the base for the upgrade of future concepts and learning…”, while the most novice level of knowledge is shown for the BI5,i.e., “… To understand the structure of matter.; I do not see this as important…”. The intention of learning these Big Ideas is also mostly on the intermediate level for all of them.

Wider personal knowledge (q3) is mostly at the novice level for all Big Ideas, except BI4 (advanced) and BI5, where there is an equal distribution between novice and intermediate levels. The novice level of knowledge is shown for difficulties/limitations connected with teaching (q4) for all the ideas except BI4 (intermediate level). Here, the number of participants expressing their knowledge at the intermediate level is the highest. Question 7 about the teaching procedures represents the knowledge about the instructional strategies, and it is at the intermediate level for all the Big Ideas (“… I will do some experiments with them and they will have to take notes and draw the experiment…; With demonstrated experiment and then we will see the video about particles in the experiment… ”). The advanced level is the least represented in this question. The exceptions are BI1 and BI6, with an equal distribution between the advanced and novice levels of knowledge. Knowledge of the assessment, questioned by question 8, about the specific ways of ascertaining students’ (mis)understanding of these ideas is mostly at the novice level. The intermediate level of knowledge is more represented than the advanced one, except for the first Big Idea.

The data from evaluating the similarities or differences among the three Croatian universities offering chemistry teachers’ education are presented in

Table 2. Comparison of the dominant level of pre-service PCK from universities (green = advanced level, blue = intermediate level, yellow = novice level).

	Uni.	BI1	BI2		BI3	BI4		BI5		BI6		BI7
What do you intend the students to learn about this idea?	A	N	N		N	I		I		I		N
	B	A	I		I	I		I		I		I
	C	I	I		I	I		I		I		I
Why it is important for students to know this?	A	I	A		I	I		A		I		I
	B	I	I		A	A		I		I		I
	C	N	I		N	A		N		I		I
What else might you know about this idea (and you do not intend for students to know yet)?	A	N	N	A	I	A		I		I		N
	B	N	I		A	I		N		N		N
	C	N	N		N	N	I	N		N		N
Difficulties/limitations connected with teaching this idea.	A	I	I	A	I	I		A		A		A
	B	N	N		N	A		N		N		N
	C	N	N		N	N		N		N		N
Knowledge about students’ thinking which influences your teaching of this idea.	A	N	N		N	N		N		N		N
	B	I	N		N	N		N		I		N	I
	C	N	N		N	N		N		N		N
Other factors that influence your teaching of this idea.	A	N	N		A	N	A	N	A	I		N
	B	N	N		N	N		N		N		N
	C	N	N		N	N		N		N		N
Teaching procedures (and particular reasons for using these to engage with this idea).	A	I	I		I	I		I		I		I
	B	I	N	I	N	I		N		A		I
	C	N	I		I	I		I		I		I
Specific ways of ascertaining students’ understanding or confusion around this idea.	A	N	N		N	N		N		N		N
	B	N	N		I	N	I	N		N	I	N
	C	N	N		N	N		N		N		N

. In each square, a predominant level of pre-service chemistry teachers’ knowledge is presented. Again, the novice level is marked yellow and blue represents the intermediate level, while the green color stands the for advanced level. If the distribution of answers is equal for the two levels of knowledge, the square is divided into two and colored with the two colors representing these levels of knowledge.

Since the participants are the same, the dominant level for each of the three universities mostly follows the results for the initial level of PCK of pre-service teachers (Figure 1), with minor differences between the universities. In general, most of the pre-service teachers’ pedagogical content knowledge is at the novice level. The exceptions are the questions about the intention and importance of learning these ideas (q1 and q2) and teaching procedures (q7) for all three universities.

The highest level of knowledge is seen for all the universities and all the Big Ideas for the first question. Here, the majority of the pre-service chemistry teachers from all three universities are on the intermediate level. Comparing the universities, however, the novice level is expressed by the majority of the future teachers at university A. This is especially true for BI1, BI2, BI3 and BI7. A similar picture can be seen for the second question, however, there the lowest level of knowledge is presented by the future teachers at university C. Considering the Big Ideas, the novice level is rated for BI1, BI3 and BI5. The second question is also a question with an advanced level of knowledge represented at all three universities—for BI2 and BI5 at university A and BI3 and BI4 at university B, while pre-service teachers from university C presented an advanced level for BI4.

The knowledge question in the third question shows a rather heterogeneous distribution among the universities. The highest level is seen at university A, while the lowest is at university C. The novice level is presented for all of the Big Ideas at university C, with an exception for BI4. This Big Idea has an equal distribution of novice and intermediate levels of knowledge. Speaking of the Big Ideas, the lowest level of knowledge of future teachers presented for BI1 and BI7. On the fourth question, there is no novice level presented at university A while, on the other hand, this is the only level presented by the pre-service teachers from university C. The novice level is also expressed by the future teachers from the university B, with an exception for BI4 (advanced level). This same Big Idea has a different level of knowledge at all three universities.

A novice level of knowledge is expressed by the majority of pre-service teachers on the fifth question. Only for the Big Ideas 1 and 6, the expressed level is intermediate at university B. The same university’s presented levels for BI7 is both novice and intermediate. Comparing the Big Ideas, no intermediate or advanced level is seen for Big Ideas 2, 3, 4 or 5. For the next question, the lowest level is expressed by the pre-service teachers from universities B and C. All three levels of knowledge are seen for university A: intermediate for BI6, advanced for BI3 and an equal distribution between novice and intermediate for BI4 and BI5. The expressed level for other Big Ideas is in accordance with the level expressed by the future teacher from the other two universities.

For the seventh question, the most frequent level of knowledge presented is intermediate. While this is the only level presented at universities A and C (the exception is BI1 with novice level), it is one of the three levels presented at university B. Considering the Big Ideas, the intermediate level is seen for BI4 and BI7 at all three universities. The highest level is expressed for BI6 at university B (advanced), while knowledge is at the intermediate level for the same Big Ideas at the other two universities. The last question has a similar distribution of knowledge levels as the fifth one. The novice level is presented by the future teachers from universities A and C for all of the Big Ideas. Although future teachers from university B expressed all three levels of knowledge, the novice one is the dominant one.

Considering the overall look of the Big Ideas, pedagogical content knowledge is at the highest level for all three universities about the particle structure of matter (BI4), followed by the Big Idea about the movement of particles (BI6). No obvious difference is seen for the other Big Ideas.

6. Discussion

The present study aims to determine the awareness of pedagogical content knowledge and the level of it among pre-service chemistry teachers in Croatia, who are evaluated before the educational reform started. Thus, a clear picture of the existing knowledge should be presented. It can serve as a good starting point for chemistry education teachers at the three universities to adapt their lectures and seminars to bring to consciousness pre-service chemistry teachers’ PCK on Particle Theory. The results show that pre-service chemistry teachers’ PCK is either novice or intermediate on the national level, while the results for particular universities show a greater span of PCK.

The novice level is the dominant level of PCK on the national level. This is in accordance with the time point of the research (before chemistry education courses). The (un)conscious pedagogical content knowledge of Particle Theory at all three universities can be seen. General pedagogical courses taken before the research seems to have left a mark on pre-service teachers’ PCK. The dominant level of instructional strategies and curriculum is at an intermediate level. This creates a good foundation for science education course educators to develop and broaden pre-service teachers’ PCK.

However, there is a greater difference in levels of knowledge among universities for some of the questions and Big Ideas. A higher level of PCK is expressed for the questions connected with the curriculum (first and second one), as well as for question 7 about teaching procedures. A wider range of levels of knowledge is seen at university B for the question about teaching procedures. This can be explained by the already taken pedagogical courses. However, this is the case for all participants. In the Croatian educational system, there are three main general education courses: psychology, attended by all of the participants at this time point; didactics, attended by the participants from universities A and B; and pedagogy, which took place at universities A and C. Since in Croatia no general unique curricula for teacher education courses exist, all of the teacher educators (who can be pure chemists, not obligatorily science teachers) can offer content of their preference, which can be adapted to educational needs, as well as to pre-service teachers’ prior knowledge.

This raises two general questions about Croatian university teachers’ education, namely (a) about the organization and time point of the mentioned general education courses attended before the science education course: Should the timetable be unique for all three universities, and if so, which general education courses should be attended before science education courses or, even, should it be all three and (b) about the general curricula for university teacher education? Should there be a general curriculum for teacher education? In addition to that, the dominant level of knowledge, for the majority of questions, is the highest at university A. It is the only university at which future teachers attended all general education courses before the science education courses started.

Our answers to this are (a) yes and (b) yes. Without remaking the whole structure of the Croatian university chemistry teacher education program, we feel allowed to make some suggestions and propose first ideas about it.

Future teachers from all three universities are aware that visualization, especially at the particle level, is important in Chemistry lessons. It can be achieved by drawings on the particle level. Another way, which is even better, is connecting the macroscopic view (experiment) with the microscopic view (particle level). This stands in line with more student-centered teaching planned in the curriculum reform. Some of the participants mentioned that particle view was not very much in focus in their academic education (some of them underline during the university courses). Despite the lack of internships in school, future teachers are aware that unpreparedness for lessons and lack of knowledge (and experience) can influence teaching the mentioned Big Ideas. Since their answers are not based on their internship, it can be concluded that future teachers often copy the teaching and learning procedures from their own school time. This is not bad if desirable behavior and actions are copied—the ones that are in line with recent reforms and teaching and learning theories. Thus, we suggest more reflection on teachers’ beliefs and knowledge about their own teaching and learning practices and their assimilation or accommodation to the needs of educational reform.

Pre-service teachers’ PCK about Particle Theory is more content-focused teaching, which is contrary to the new education reform. The pedagogically reasoned approach is missing due to the time point of the research and the participants’ lack of experience in school. Speaking of the Big Ideas, there should not be much difference in the level of knowledge between them considering the previous chemistry courses. Some higher level of PCK is shown for the first and fourth Big Idea on the national level, as well as for the fifth on the university level. These Big Ideas are something that has been taught since primary school (grades 7 and 8), and participants were aware of them for much longer than with other ones. Due to the time point, the expected level of knowledge is novice or intermediate for all of the questions. Indications of reflections on teaching and learning about Particle Theory can be seen, but there is a lack of awareness of the pedagogical content knowledge. We suggest focusing on this issue in chemistry education courses as well.

We see this study and its results as an excellent starting point for chemistry teacher educators at the three Croatian universities for further development of the PCK of pre-service teachers, especially to make them aware of their pedagogical content knowledge and develop it in the spirit of the new educational reform. Future science education courses and internships should help pre-service teachers upgrade their knowledge of assessments, learners and science teaching. A bigger emphasis should be on making the pre-service teachers aware of their wider knowledge of the Big Ideas and the importance of teaching them.

7. Conclusions

Pedagogical content knowledge is something that cannot be learned by heart or from textbooks. Teachers, both pre-service and in-service, are often unaware of its existence, so greater stress should be, first of all, on the determination of PCK, as well as on the development of PCK. Content Representation (CoRe) can help pre-service teachers to plan their lessons [13], while it is also a great deal of help for science education courses for understanding the pedagogical content knowledge and development of teaching particular concepts. CoRe offers help to the pre-service teachers in a different way than traditional kinds of curriculum materials offer. It can help in recognizing components of effective practice and problematizing content and pedagogy [7].

Knowledge about teaching and learning strategies, as well as curriculum, is at an intermediate level. The initial PCK of Croatian chemistry pre-service teachers is on the novice level for the limiting factors that can influence teaching, as well as for the ascertainment of understanding, which is in order due to their lack of expertise and not yet attending chemistry education courses. PCK is knowledge about how to teach particular content in a particular way due to the circumstances of teaching [5]. As mentioned above, it cannot be learned, it is something that teachers, both pre- and in-service, gain through the years of teaching. The development of one is a complex process influenced by different factors, such as learning environment, age, subject content, etc. One of the sources of PCK development is specific courses/workshops during teacher education courses. However, the very first step is making pre-service teachers aware of the existence of it, followed by the determination of its level. Questionnaires such as this are a great deal of help for the determination of the level of knowledge. By the fulfilment of it, the CoRe for all (main) topics in chemistry can be made in science education courses, since the CoRe is a great deal of help for pre-service teachers [5]. Pre-service teachers must become aware that they need to have excellent content knowledge about the subject, as well as pedagogical knowledge. Since the science education course is the last one pre-service teachers attend before graduation, it is a very big and important task to determine the possible science misconceptions of pre-service teachers before they become in-service teachers.

This is an excellent starting point for the teachers of science education courses to see what to put greater stress on while planning their courses. It gives a scanning of pre-service initial PCK, which allows further research of their PCK after science education courses and at the end of their university education. This can give a wider picture of the pedagogical content knowledge about one of the ground concepts in chemistry and enable monitoring of the development of individual PCK under various influences. Science teacher education should pay more emphasis both on raising awareness of PCK as well as its development.