Characterisation of teacher professional knowledge and skill through content representations from tertiary chemistry educators

Abstract

An established tool for collating secondary teachers’ pedagogical content knowledge (Loughran's CoRe) has been adapted for use by tertiary educators. Chemistry lecturers with a range of levels of experience were invited to participate in workshops through which the tool was piloted, refined and applied. We now present this refined tool for the tertiary teaching community to consider adopting. The teaching approaches of over 80 workshop participants were collected using the tool in a broad survey of tertiary chemistry teaching strategies. Participation in the workshops led to a significant gain in personal PCK for some individuals. Analysis of responses received in the workshops revealed that the consensus model of secondary teacher professional knowledge and skill is also applicable to the tertiary level, and that the CoRe is a useful way to gain insight into the knowledge bases and topic-specific professional knowledge of tertiary chemistry teachers. The data were aggregated and coded inductively to distil the types of strategies commonly found to be useful for teaching particular tertiary chemistry topics. This resulted in collation of over 300 teaching strategies for 19 different chemistry topics, representing significant topic-specific professional knowledge of tertiary practitioners. To share and sustain this collection of teaching strategies, a website was built that is searchable by either chemistry topic or by type of teaching strategy, making it immediately useful to practitioners. Usage analytics data for the website confirm that many users have accessed the resource, showing that this is a practical way to transfer information between chemistry educators.

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Introduction

The concept of pedagogical content knowledge (PCK) was introduced by Lee Shulman after he observed that the focus for examining pre-service teachers had shifted from content knowledge during the late 19th century, to teaching procedures in the 20th century (Shulman, 1986). He identified a blind spot with respect to content in research into teaching as the missing paradigm (p. 7), and listed aspects of PCK “the most useful forms of representation…, the most powerful analogies, illustrations, examples, explanations and demonstrations… the ways of representing and formulating the subject that make it comprehensible to others” (p. 9). In a second work, Shulman noted that PCK is “that special amalgam of content and pedagogy that is uniquely the province of teachers” (Shulman, 1987, p. 8). Since then, PCK has been recognised as a central notion in characterising effective science teaching and has been explored by many researchers, resulting in a series of books (Gess-Newsome and Lederman, 1999; Loughran et al., 2012; Berry et al., 2015). Investigations of PCK originated in the primary and secondary education contexts, where the practices of experienced teachers have been studied in an attempt to characterise what makes their teaching effective for specific topics. Seminal work on PCK in the secondary context, that forms the theoretical basis for the current project, was published by Magnusson et al. (1999), establishing a widely-used model for PCK. According to this Magnusson model, the five components of PCK are “(a) orientations toward science teaching, (b) knowledge and beliefs about science curriculum, (c) knowledge and beliefs about students’ understanding of specific science topics, (d) knowledge and beliefs about assessment in science, and (e) knowledge and beliefs about instructional strategies for teaching science.”

In 2012, a PCK Summit involving recognized leaders in the field of secondary science PCK research was organized, and a book reporting the outcomes of that meeting was subsequently published (Berry et al., 2015). As a result of the deliberations at that summit, a consensus model that is more sophisticated and granular than previous frameworks for PCK was proposed (Gess-Newsome, 2015). This model is presented in Fig. 1 and a key feature is that PCK is differentiated from topic-specific professional knowledge (TSPK). PCK now appears within classroom practice as an output of TSPK, after passing through the filter of teacher beliefs, orientations, prior knowledge and context. Thus, within this framework TSPK is transferrable but PCK is not.

Fig. 1 Consensus model of Teacher Professional Knowledge and Skill (TPKS) including PCK. From Gess-Newsome, 2015, p. 75. [Reproduced with permission].

The components identified by Magnusson and colleagues can be seen to fall within three different aspects of this model: orientations towards science is an amplifier or filter of the professional knowledge bases of teachers, which include both the curriculum and assessment; knowledge about student understanding and instructional strategies are considered TSPK.

Considering the model from top to bottom, TSPK is seen as a source of personal PCK with several filters and amplifiers influencing the nature of personal PCK that an individual teacher develops and enacts in the classroom. Conversely, moving from bottom to top, personal PCK can act as a source of TSPK, similarly mediated via individual filters and amplifiers. The filters and amplifiers such as beliefs and orientations are particularly relevant to this study considering the diverse background of the participating tertiary teachers. Thus, the double-headed arrows connecting the different factors impacting student outcomes are important since they potentially define the relationship between TSPK and PCK and how this develops.

We have applied this consensus model, designated Teacher Professional Knowledge and Skill (TPKS), in the present study and we observed that the thinking and strategies that emerged through this project are aligned with this model. In an early report examining tertiary PCK, Fernández-Balboa and Stiehl (1995) used interviews to elucidate components of good tertiary teaching from eminent teachers across many fields. They categorised five generic PCK components: “knowledge about (a) the subject matter, (b), the students, (c) numerous instructional strategies, (d) the teaching context, and (e) one's teaching purposes.” Within each of these headings, commonalities were found across disciplines and the integration of these elements was considered to be the key feature of excellent teaching. These five components differ only slightly from the five components found by Magnusson and coworkers (1999) for secondary teaching. The most significant difference between these sets of components is the explicit inclusion of assessment in Magnusson's model, which is absent from the earlier model. In this project we found that tertiary educators do consider assessment as a key component to planning their teaching and so the Magnusson model was more suitable.

In the following decade, Major and Palmer (2002; 2006) used PCK as a lens to interpret their interviews with tertiary teachers representing multiple disciplines who had chosen to take part in a university-wide program to implement problem based learning (PBL). The major themes the teachers identified as influencing student learning were: their goals for student learning; the cultural context; the students themselves; the curricular structure; and their own pedagogical efforts. It was found that participation in the program had enhanced the tertiary teachers' PCK because they had thought deeply about how to enable student learning.

Since PCK is considered to be evident through teaching practice, researchers have attempted to capture it both for characterisation and to look at ways that it can be transferred to other teachers. One of the most popular tools to collate individual approaches representing PCK for secondary science was developed by Loughran and colleagues (Loughran et al., 2004; Bertram and Loughran, 2012). The tool consists of the Content Representation (CoRe, listed in Table 1), which aims to characterise a teaching strategy for a specific ‘big idea’, combined with individual Pedagogical and Professional-experience Repertoires (PaP-eRs), which give specific examples of classroom practice (Bertram and Loughran, 2012). Loughran's model involves teachers completing a CoRe for several big ideas within a specific content area (either individually or collaboratively) and then fleshing this out with several PaP-eRs. PaP-eRs are accounts of teachers’ thinking when preparing a lesson plan and serve to articulate how their knowledge is put into practice. The process of completing the CoRe and PaP-eRs in itself develops and strengthens teachers’ PCK.

Table 1 CoRe questions (from Loughran et al., 2004)

(1) What do you intend the students to learn about this idea?

(2) Why is it important for students to know this?

(3) What else do you know about this idea that you do not intend students to know yet?

(4) What difficulties and limitations are connected with teaching this idea?

(5) What do you know about students' thinking that influences your teaching of this idea?

(6) What other factors influence your teaching of this idea?

(7) What teaching procedures will you use; why have you chosen them to engage with this idea?

(8) How will you ascertain students' understanding or confusion around this idea?

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The information collected through the CoRe questions forms part of TSPK within the consensus model shown in Fig. 1. The CoRe tool is accepted as a valid and well-characterised strategy to elicit understanding of teacher practice (Aydin and Boz, 2013). However, this set of questions was originally developed for use by secondary teachers and there is no parallel tool currently available for tertiary teaching in STEM disciplines. In the tertiary context, PCK is an emerging field of research and reports reveal similar insights into teachers’ topic-specific professional knowledge, and build on the foundational knowledge about teaching practice from the secondary context.

Several studies have investigated tertiary PCK specifically in the field of chemistry and researchers have applied the CoRe as follows. In 2004, Bucat examined common misconceptions held by undergraduate chemistry students, in some cases caused by poor teaching practices or representations, and called for a greater application of PCK as a way to improve tertiary teaching of chemistry. In 2008, an adaptation of Loughran's CoRe was published within an investigation of the PCK through interviews and written responses of four chemistry professors in the area of “amount of substance” (Padilla et al., 2008). These researchers modified the CoRe to focus their study on historical, epistemological, philosophical and science, technology and society aspects of the content, and their question set was not trialled prior to use. They found that teachers with different conceptual profiles teach the same content in different ways. Similarly, Davidowitz and Rollnick (2011) used a CoRe to capture the PCK of an experienced organic chemistry professor. A refined model for PCK resulted from this work, with beliefs about teaching given an underpinning role. In parallel to this study, Padilla and van Driel (2011) applied and adapted the Magnusson components specifically for the tertiary context, and they generated an extensive table of subcomponents based on interviews with six quantum chemistry professors. A close analysis of the relationship between these components for their interviewees revealed commonalities and differences depending on the specific subdisciplinary backgrounds of the individuals studied.

More recently, Fraser (2016) conducted interviews with 9 academics from different science disciplines to determine whether the Magnusson PCK construct was applicable at the tertiary level. She confirmed the five components identified by Magnusson and proposed including the component of knowledge and beliefs about context, originally from Grossmann's (1990) PCK model, as important to the tertiary teachers. However, assessment was not significantly mentioned within her study.

Thus it can been seen that the concept of PCK has been found to be useful for considering science disciplinary teaching approaches at the tertiary level, particularly in chemistry, and several studies have begun to collate tertiary PCK for specific topics. However, several key differences between the processes of development and application of PCK are evident when comparing the secondary and tertiary contexts and these are important to explore further.

First, it has been observed in the secondary sector that teachers' PCK is sometimes limited by the depth of their subject matter knowledge; for example, poor understanding of the mole concept hinders their ability to explain it well to students (Rollnick et al., 2008; Kind, 2014; 2017). In addition, analogies used within textbooks can be confusing to teachers, who may recognise that their usage may inhibit student learning but be unable to provide more accurate analogies (Harrison and Treagust, 2006). In contrast, the majority of tertiary science teachers have completed a doctorate, typically followed by several years of postdoctoral work where they are immersed in their research field, applying their theoretical knowledge in practical studies (Fig. 2). This differentiates their prior experience and knowledge from most secondary teachers and allows them to draw upon a deeper subject knowledge base as they build their TSPK (Kane et al., 2004 and references cited therein). However, this depth is only applicable when teaching within their content expertise, and anecdoctal evidence suggests that it is not uncommon for chemistry academics to be teaching outside their subdiscipline area, particularly in first year chemistry. This parallels the situation of high school teachers who are often required to teach outside their main teaching area (Kind, 2014) and was one motivation for the collation of resources and development of a website as an outcome of this study to assist tertiary teachers' professional development.

Fig. 2 Typical career progress of a science academic illustrating professional development in teaching and the position of this project.

A further important difference between the contexts of secondary and tertiary teaching is that in secondary schools, teachers have substantial time (two or more years) to get to know their students within a class of typically under 30 children. In the tertiary context, relationships must often be built within a single semester in classes that can have several hundred students. This affects the strategies that tertiary teachers adopt to build relationships with students.

A final difference is that secondary teachers are explicitly trained in PCK, and their professional development includes teaching strategies as well as knowledge of student difficulties. Such training is absent from the typical career path of a tertiary teacher (illustrated in Fig. 2).

Professional academic development for incoming tertiary teachers has become a requirement at most institutions in the form of generic courses addressing curriculum, teaching practice and assessment. However, discipline-specific professional development is less common. Most teaching academics derive their teaching strategies from their teaching experiences (Oleson and Hora, 2014). Other important sources of teaching strategies are discussions with colleagues and reflections on student feedback from student evaluations. The current lack of discipline-specific professional development in tertiary teaching was a motivation for this project and we aimed to improve awareness of tertiary chemistry PCK.

Although several studies have examined the PCK of a small number of selected tertiary chemistry teachers (Padilla et al., 2008; Davidowitz and Rollnick, 2011; Padilla and van Driel, 2011; Aydin and Boz, 2013), to date no study has attempted to complete a broad survey of TSPK from a large number of participants. The overall aim of this project was to distill transferrable and acquirable aspects of TSPK in tertiary chemistry teaching into a format that could be transmitted, as shown in Fig. 2. The long-term objective was to accelerate the rate at which early career academic staff improve their teaching. In order to do this, we conducted workshops to collate topic-specific teaching strategies from groups of academics of different levels of experience, first using the CoRe questions and later with a modified CoRe more suitable for the tertiary level. The large volume of collated information was then built into a website to enable sustained transfer of useful strategies.

This study is underpinned by a grounded theory approach to identify themes that characterise tertiary chemistry teaching. The original theoretical framework underpinning the study was PCK based on Magnusson's (1999) components, and when the new framework in Fig. 1 was published during the course of the project, we chose to adopt it as a consensus model to inform our analysis based on inductive coding of qualitative data.

The research questions addressed in this study are:

(1) “What insight can the CoRe questions provide into tertiary chemistry Teacher Professional Knowledge and Skill?”

(2) “How can transferable tertiary Teacher Professional Knowledge and Skill be shared with novice tertiary teachers?”

In addition to answering these research questions, we report the outcomes of a deductive, open-ended coding process that was adopted to explore the diverse range of teaching strategies reported by participants within the workshops.

Methodology

The context of this study was tertiary chemistry teaching in Australia. Participants representing a total of 25 different institutions participated in a series of workshops. Two of those workshops were facilitated at national science conferences, taking advantage of large numbers of participants with an interest in chemistry and science education. Participants at conference workshops were invited through an abstract describing the project submitted for the conference. A further three workshops were hosted at individual tertiary institutions in Queensland and Western Australia. Participants were recruited for institutional workshops through purposeful individual email invitations to academics who were recognised as having an interest in chemistry education.

Institutional ethical approval (QUT Ethics Approval Number 1400000568) was secured prior to beginning data collection and at each workshop, participants were invited to provide informed consent for their responses to be included in this study. During the workshops, after a brief introduction to the concept of PCK, participants completed worksheets comprising the CoRe questions with blank response fields. This was conducted in parallel to extensive discussion in small groups of PCK, the questions within the CoRe, topics that were important to the participants, their teaching strategies and challenges.

Each workshop participant was free to select the ‘big idea’ for their CoRe, so these address a wide range of chemistry topics, primarily situated in first year tertiary chemistry. If participants were unsure about which topic to choose, they were prompted to consider the topic of equilibrium because this is recognised to be one of the most challenging topics for chemistry students (Wheeler and Kass, 1978; Huddle and Pillay, 1996; Tyson et al., 1999; Voska and Heikkinen, 2000; Harrison and de Jong, 2005). Thus, the weighting of responses for this topic was higher than for other topics.

The pilot workshops used the original CoRe, as developed for secondary teaching by Loughran, with the addition of one question as described below. However, observations revealed that some of the CoRe questions were not directly applicable to the tertiary context. This was evident through two outcomes – either specific questions were consistently left blank, even when there was ample time during a two hour workshop aimed at completing the CoRe, or responses were repeated by participants for several of the CoRe questions or included phrases such as “see above”. For the second workshop held at a conference where only a 40 minute period was available, a shortened version of the CoRe was used consisting of only questions 1, 4, 5, 7 and 8 (Table 1).

The specific questions that were frequently left unanswered by participants, or where the answers were the same for several questions, were:

Q3. What else do you know about this idea (that you do not intend students to know yet)? (usually left blank)

Q4. What are the difficulties/limitations connected with teaching this idea? (Answers were often identical to “what do you know about student thinking”, or participants wrote “see above”.)

Q6. What other factors influence your teaching of this idea? (usually left blank)

Thus, these questions were removed from the CoRe used in the final workshop for brevity and to encourage engagement with the remaining questions. In addition, for the purposes of collating useful information to compare novice and experienced tertiary teachers, we added an additional question to the CoRe at all five workshops: What was the source of your teaching strategies? Other studies have specifically asked subjects for types of experiences that have influenced teaching (Oleson and Hora, 2014). Given our interest in the on-going professional development of teachers this was highly relevant to our study, because if we hope to influence tertiary teachers to modify their behaviour it is of interest to know what sources they have already adopted.

Further, some of the wording of the original CoRe questions was modified to reflect the typical language with which tertiary teachers are familiar. This included separating the original CoRe question “What are your teaching procedures (and particular reasons for using these to engage with this idea)?” into two separate questions, asking first what and then why.

Thus, the final set of CoRe questions developed for tertiary teaching (hereafter called CoRe+ questions) is as follows:

(1) Identify one ‘big idea’ (or topic) that you teach.

(2) What is most important for students to know about this idea?

(3) Why is it important for students to know this?

(4) What do you know about your students' thinking that influences your teaching of this idea?

(5) What teaching strategies will you use?

(6) Why have you chosen these teaching strategies to engage students with this idea?

(7) What was the source of these teaching strategies?

(8) How will you ascertain students' understanding or confusion around this idea after teaching them?

It has been demonstrated previously that a modified version of the CoRe can achieve the same purpose of the original CoRe in collecting and evidencing tertiary participants’ chemistry PCK in a concrete way (Padilla et al., 2008). However, it was considered important to gain validation through consultation with the original author of the CoRe tool, John Loughran, as a member of our project steering group along with two additional internationally regarded tertiary chemistry educators (Roy Tasker and Bob Bucat). This panel of experts agreed that the modifications made to the CoRe were appropriate to the context so final CoRe+ questions were used in the final workshop where they stimulated extensive and useful discussions for participants. Table 2 shows the types of locations and sizes of the workshops.

Table 2 Summary of workshops held within this project

Workshop number	Conference or institution	Version of CoRe used	Number of participants (number of institutions represented)	Discussion style
1	Conference	Loughran	35 (22)	Individual and small groups
2	Institution	Loughran	5 (2)	Individual
3	Conference	Shortened Loughran	25 (18)	Small groups
4	Institution	Loughran	12 (3)	Individual and small groups
5	Institution	CoRe+	8 (3)	Individual

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In some cases, groups submitted a CoRe+ worksheet that represented their combined perspectives whereas in others, each participant prepared an individual CoRe+ worksheet. The completed documents were transcribed and subjected to inductive thematic analysis using NVivo (QSR International). In addition to the written CoRe+ sheets, during several of the workshops audio recordings of participant discussions were collected, which were then transcribed. Due to the large number of participants in separate groups, resulting in noisy environments, and because of limited recording capabilities (only one or two groups' discussions were recorded) the recordings do not represent all participants. Nonetheless the transcripts of the discussions are revealing and these enabled quotes to be validated and attributed as individual case contributions to the analysis. In the discussion below, all quotes are from written worksheets except where otherwise noted.

Coding within NVivo began with creating a parent node for each question. Child nodes that emerged inductively were used to assign responses into categories. The coding highlighted the complexity of the data because some statements could be coded to more than one child node, and there was often overlap between responses to different questions but these were coded only to a single node for that question. For example, a participant's written comment “Don’t understand concepts of mole and can’t visualise it.” was coded to the child node ‘Visualisation' in response to CoRe+ question 4. The data was recoded to make sure that unreasonable bias towards any theme through replication of coding was minimized. Interrater reliability between two coders applied to a subset of the data was found to be satisfactory.

As part of the process of formulating transferable PCK to support the professional development of new tertiary teachers, a website (http://chemnet.edu.au/chem-pck) was designed and built from the body of data derived from the workshops as a sustainable way to offer professional development to individual academics worldwide. Reflecting on common discussions within the workshops, it was anticipated that the capacity to search for teaching strategies based on the specific chemistry topic would be most useful. Strategies were also classified within types so that users could easily find what might work in their specific institutional context. The list of strategies together with participant quotes form the basis of the content of the ChemPCK website. Hyperlinks to YouTube videos and other online resources were added and checked for currency. Note that a separate study based on interviews also contributed data to the website. Usage of this website has been monitored through Google Analytics and represents an additional data source for the project.

Results and discussion

In alignment with the work of Major and Palmer (2002; 2006) and Fraser (2016), it was observed that many participants in the workshops reported having found the workshop experience itself very valuable. A number of the participants had not previously encountered the concept of PCK or tried to express their teaching strategies. Reflective practice in thinking about and articulating their teaching strategies was a new concept that many participants found would help their own practice immediately. This parallels the findings in pre-service and early career teacher training of Hume and Berry (2011; 2013) and Williams et al. (2012). Both of those research groups involved junior teachers with experts in the process of developing CoRes and found that this approach was effective in accelerating development of PCK in novice teachers.

Thematic analysis of the data collected from the workshop participants for CoRe+ question 1 generated a list of 19 commonly taught chemistry topic areas. For ease of analysis, these were grouped by the project team into either general chemistry or one of three recognised chemistry subdisciplines: organic, inorganic and physical chemistry. This subdiscipline classification was also useful for searchability within the website, as discussed below. Table 3 provides the full list of topics derived from analysis of the data and their corresponding subdisciplines.

Table 3 List of chemistry subtopics chosen by workshop participants for CoRe+ question 1, assigned into subdisciplines

Chemistry subdiscipline	Topic chosen by participant
General chemistry	Electronic structure–electronegativity-shape
	Nature of matter
	Practical chemistry
	Stoichiometry/equations/formulae
Organic chemistry	Functional groups
	Mechanisms
	Organic structure and bonding
	Stereochemistry
	Structure determination/spectroscopy
Inorganic chemistry	Acid/base chemistry
	Electrochemistry
	Aqueous solution/ionic chemistry
Physical chemistry	Chemical and physical properties
	Equilibrium
	Intermolecular forces
	Kinetics
	Phase transitions
	Quantum mechanics
	Thermodynamics

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It should be noted that although this list of chemistry topics parallels much of a typical tertiary chemistry curriculum it is not claimed to represent the entire curriculum. The list necessarily has gaps due to the limited number of participants in the workshops. In particular, no workshop participant chose topics that could be classified within the subdisciplines of analytical chemistry or biochemistry that would complete the set of subdisciplines in Table 3. Nonetheless, there is significant overlap between the topics chosen by participants in this study and those published in the Anchoring Concepts lists from the American Chemical Society's Examinations Institute (Holme and Murphy, 2012; Raker et al., 2013).

The second and third CoRe+ questions, that explore what is important for students to know about this topic and why, were observed to be critical to a self-reflection phase of the workshops. When articulating their responses to these prompts, tertiary teachers took an overarching perspective on their teaching. From the answers provided and informal discussions and feedback from participants, it was clear that reflection on why the content is important also informed the choice of what in particular was considered most important. For example, a workshop participant reflected:

‘What I tell my students from the very beginning is that it is vitally important for their understanding of chemistry that they understand that molecules are three-dimensional things and that they have a spatial requirement in that they have a shape of their own and that shape will change. They can't do higher level manipulations without an understanding of three-dimensional nature of molecules.’

Applying a grounded theory approach to analyse the data that were collected in response to the CoRe questions, a set of child nodes arose inductively that were aligned with the notions of PCK that have been reported previously. Fig. 3 displays the child nodes derived from analysis of the answers provided to CoRe+ question 3, listed in order of decreasing frequency. These have been mapped based on the workshop data to the corresponding PCK component established by Magnusson.

Fig. 3 Child nodes derived from answers to CoRe+ question 3 mapped to Magnusson's PCK components. Numbers of references provided by workshop participants are given in parentheses in left hand column.

The responses provided in Fig. 3 support our hypothesis that, while tertiary teachers may not have encountered the term Pedagogical Content Knowledge, they nonetheless structure their thinking about their teaching in ways that parallel the recognised PCK components. Note that no responses were received in the last category regarding instructional strategies for this question because these were asked for explicitly in CoRe+ question 5.

The CoRe+ question 4 “what do you know about your students' thinking that influences your teaching of this idea?” probes fundamental components of TPKS shown in Fig. 1. The child nodes representing the themes that emerged through analysis of responses to this question and the frequency of each are displayed in Fig. 4.

Fig. 4 Child nodes of knowledge of student thinking that influences teaching cited by workshop participants, ordered by frequency.

Thus, it is evident that tertiary teachers are very aware that students entering their class have prior knowledge and understanding. This forms part of their knowledge base (knowledge of students) in the same way as is recognised for secondary teachers and shown in Fig. 1. Many workshop participants referred to their students’ diverse high school preparation or experiences, for example:

‘Having to relearn something that they thought was true from school. Not understanding the evolving nature of science. New knowledge easier to assimilate than changing old knowledge.’

‘I was shocked last year. I said, “Okay, you've all seen Lewis Dot Structures. We're going to go through them really quickly. Put your hand up if you've never seen a Lewis Dot Structure.” There was a significant number who put up their hand. Okay, “Put your hand down if you've never done senior chemistry in which case you were advised not to do this course in the first place.” Two or three people put down their hands. There's still a few. Then after the lecture a few of them came up to me and said, “Oh, I've seen those but we never called them Lewis Structures.” So they couldn't quite understand what I was doing but we use all of this terminology that the teachers don't use. And I don't know why the teachers don't use it.’ [audio transcript, Workshop 5]

As described in the methodology, the original CoRe question “what difficulties and limitations are associated with teaching this topic?” was asked in the first four workshops. This was removed from the set of questions in the CoRe+ because of substantial overlap in the responses with those to CoRe+ question 4 “what do you know about your students' thinking that influences your teaching of this idea?” Analysis of the responses to this question do not appear in Fig. 4, and answers provided additional insight into teacher experiences of student learning. Table 4 summarises the responses to this question that are not identical to those given for CoRe+ question 4, presented in Fig. 4. As can be seen from the third column, most of the difficulties mentioned have significant overlap with themes that were identified in Fig. 4, but some are expressed differently or have different emphasis.

Table 4 Student difficulties derived from responses to CoRe question “What difficulties and limitations are associated with teaching this topic?”

Student difficulty identified by workshop participants	Number of references	Overlapping theme(s) from CoRe+ question 4 responses
Complexity-conceptual difficulty	46	Prior knowledge, difficulties with mathematics
Vocabulary-language	33	Prior knowledge, memorisation
Lack of experience-background	16	Prior knowledge
Timing within course	7	Time pressure
Gauging student understanding	7	CoRe+ question 8
Curriculum limitations	6	Time pressure
Teaching format	5	Expectations of teacher
Student diversity	4	Prior knowledge
Resource availability	3	Expectations of teacher
Relating to students	3	Expectations of teacher
Student numbers	2	Prior knowledge, expectations of teacher

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Thus, explicitly asking workshop participants to share what they perceived as teaching difficulties led to the identification of some issues that were not described when their understanding of student thinking was probed. Although these perceived difficulties are interesting to reflect upon, in terms of encapsulating TSPK for transfer to novice tertiary teachers, they are considered less important.

At the heart of TPKS lie the actual strategies adopted to convey knowledge to students. Using the iterative coding process described in the methodology, the wide range of specific teaching strategies and resources that were cited by workshop participants in response to CoRe+ question 5 were condensed into 17 teaching strategies, listed in Table 5. Each of these included multiple examples and resources. Based on the literature, five overarching types of strategy were identified by the project team and the teaching strategies were categorised deductively into these types, listed in the first column of Table 5. It should be noted that the types of strategy contain some inherent overlap, for example many visualisation strategies rely on technology (Tasker, 2014), and analogies help in the formation of mental models (Coll et al., 2005). We formulated these categories for classification and ease of searching to guide the delivery of transferable PCK through the website (described below).

Table 5 Summary of teaching strategies used by workshop participants, clustered into types of strategy

Type of strategy	Strategies cited by participants
Mode of delivery	Black or white board
	Explanation
	Examples
	Reinforcement and repetition
Representations	Analogies and metaphors
	Demonstration and simulation
	Models and representations
	Visualisation
Technology enhanced	Online and e-resources
	Other technology: clickers, multiprojection, recordings, visualiser
Content structure	Big picture focus
	Focus on fundamentals
	Link to other topics
	Real world applications
Active learning	Practice problem solving
	Student participation
	Lab-based

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The full set of child nodes that were distilled from the workshops includes a total of 310 separate teaching strategies. This is a rich collection of TSPK within the framework of Fig. 1. It must be emphasised that in most teaching approaches the use of multiple strategies simultaneously is inherent; it is difficult to pick apart an approach into single strategies. For example, a workshop participant provided the following set of steps to teaching symmetry within spectroscopy:

“(1) Use of examples (e.g. show¹H and¹³C NMR spectra of ethyl benzene).

(2) ”Model making” to display principles of symmetry.

(3) Problem solving (extensive!!)”

This set of activities includes examples, models and practice problem solving and the participant has optimised their teaching to integrate all three strategies in their teaching of this topic.

CoRe+ question 6 asked participants to explain their choice of strategies, and this justification of their choice led to intense discussion as participants explained why particular strategies are suitable for teaching particular topics. The responses were coded along with the strategies to flesh out their choices. A typical example illustrating how the strategy and choice of strategy are linked for teaching the topic of molecular shape based on the VSEPR model is:

“Make structures using balloons for molecular orbitals – visually appealing, concrete example and memorable for students. Also use a model kit to encourage students to do likewise.”

Similarly, when explaining how they teach stereochemistry, one participant also explained why they use this approach:

“Small group student-centred interaction using structured work sheets that logically develop students' conceptual understanding (learning cycle approach).”

In response to CoRe+ question 7 regarding the source of their teaching strategies, the most commonly cited source was their own experiences (Fig. 5). Whether this was as a learner, a teacher, through reflective practice or from their life experience was not separated. This indicates that teaching practices appear to develop through a personal teaching journey, aligning with the consensus model of TPKS (Fig. 1). It also shows movement in both upwards and downwards directions within that model, as classroom practice along with the professional knowledge bases of the chemistry academics inform TSPK.

Fig. 5 Sources of teaching strategies cited by workshop participants, ordered by frequency.

Indeed, the impact of the absence of formal training in reflective practice for tertiary teachers was reinforced by comments such as the response to this question from a novice tertiary teacher:

‘I developed these strategies through experience with different students’ needs. Initially I was stumped and spent considerable time identifying how they were struggling and different ways I could reach them.’ [CoRe worksheet submitted by email after workshop]

Many participants referred to the source of their strategies or resources as having been shared by colleagues, indicating the existence of informal practice and mentoring networks within tertiary institutions. Other frequently-mentioned sources included education and SoTL literature, textbooks, on-line resources and through trial and error. Relatively few mentions were made of student feedback, teacher training or tradition as sources of strategies. Considering this data in terms of the consensus model (Fig. 1), the collective TPKS of the community of practice of chemistry educators can be seen to derive primarily from PCK learned through classroom practice. This reinforces the dynamic nature of the model in that, by engaging in the workshops within this project, educators are following the upwards arrow and contributing to an atlas of shared TSPK. Perspectives gained from interactions with students, informed by the institutional context, lead to the contributions of the CoRes to TPKS, amplified in each case by the individual beliefs and prior knowledge of the participant. This finding provides a strong indication that professional development of new academics in terms of TPKS and raising their awareness of reflective practice may be effective, in particular through developing a CoRe+ (Hume and Berry, 2011).

As seen from the responses to CoRe+ question 5, tertiary teachers apply a wide range of strategies for teaching their specific content. However, they have fewer strategies for ascertaining what their students know, as evidenced by the responses received to CoRe+ question 8, shown in Fig. 6.

Fig. 6 Strategies to ascertain student understanding after teaching a topic cited by workshop participants, ordered by frequency.

This set of strategies corresponds to the assessment knowledge base of the workshop participants. The more highly favoured strategies involve an interaction between the teacher and individual student's thinking to evaluate their understanding in more active learning settings. This is often difficult to achieve for individual students in a tertiary classroom setting for large enrolment classes. There is room for more efficient feedback, including through the use of technology, which was a motivation for the development of the website to disseminate helpful strategies to practising tertiary teachers.

In order to appropriately curate the teaching strategies, the website was designed to have a simple iconographic interface that should be quick and easy to use for a range of potential users, with a minimum of clicks required to find the desired information. To remove any barriers to adoption, the website is freely accessible (no login or personal information is required). As shown in Fig. 7, the structure comprises three sets of pages: Teaching Strategies (derived from the workshops), Expert Insights (selected quotes derived from interviews with expert chemistry teachers) and Steps to Transform Teaching derived from the study data and literature.

Fig. 7 Structure of ChemPCK website (chemnet.edu.au/chem-pck).

Strategies were included in the website using the informal language in which they were provided by participants with minor editing for clarity. This ensures that they are accessible to users and reflect the terminology commonly used within this project's community. It also allows users to hear the voice of the contributor through their expression.

In order to allow searchability, each teaching strategy was input as a separate page indexed for the corresponding topic(s) and type(s) of strategy. Within both the Teaching Strategies and the Expert Insight links, users are offered drop down lists of topics and types of strategy and can set one or both of these parameters for searching. This has proven to be useful to practitioners as evidenced by the receipt of unsolicited emails from users who have found helpful strategies to teach a specific chemistry topic.

The Steps to Transform Teaching developed out of the project team's reflections. We found significant overlap in the advice being offered to improve teaching efficacy within many of the workshop and interview transcripts as well as in the extensive literature that has shown what teaching practices are most effective (M. K. Smith et al., 2009; Freeman et al., 2014). In order to summarise the common threads that were observed, we built a succinct yet practical guide including seven steps, illustrated by the graphic shown in Fig. 8.

Fig. 8 The developed set of sequential steps to transform teaching.

Each of the sequential numbered steps is a clickable link leading to a page with a short description of best practice in that area. Some include hyperlinks to relevant resources and all are based on the TPKS of participants in this project and the literature.

Initial engagement with this website, which was launched in February 2016, has been measured through Google Analytics. During the first 11 months of usage, the website attracted 500 users from 35 different countries. A subset of the analytics data is presented in Table 6.

Table 6 Summary of first 11 months of use of ChemPCK website

Web page	Page views	Unique page views	Average time spent on page (seconds)	% sessions viewed as the second page
PCK home page	696	481	79	12
Teaching strategies	777	305	41	61
Expert insights	355	188	52	21
Steps to transform teaching	377	216	79	15

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The observation that the Teaching Strategies page has been most popular supports our claim that teachers actively seek to engage with shared practice. There are existing examples of communities of practice within subdisciplines of chemistry (Benatan et al., 2009) but it seems there is also demand for an online resource that covers all topics in chemistry at all levels. As can be seen in Fig. 9, the activity on the website has been sustained and the site continues to attract users.

Fig. 9 Timeline of the number of views of ChemPCK website (all pages). A technical issue caused loss of January–June 2017 data.

Limitations of this study

Workshop participants were invited based on their interest in chemistry or science education, so there was no shortage of enthusiasm and interest in being involved in the project. However, since there was no purposeful sampling based on teaching experience, the participants were diverse in this attribute and could not be filtered. Hence the strategies have been collated together without analysing differences between expert and novice teachers. Note that our concurrent study of expert TPKS through detailed interviews will be published separately.

Professional development for tertiary teachers has been recommended to be implemented via communities of practice (Adlong et al., 2004; E. R. Smith et al., 2013) or learning communities (Gees et al., 2009). A review of the literature to 2011 found that simple provision of teaching materials is not effective at promoting change in instructional practices (Henderson et al., 2011), and instead long-term strategies are required that align with the beliefs of the tertiary teachers. Regarding website adoption, omitting logins because they may be a barrier to uptake means that no information about users is available.

Conclusions

Application of the CoRe+ tool provided significant information about the professional knowledge bases and the TSPK of tertiary chemistry teachers within the consensus model of TPKS. Thus, this tool has been shown to be relevant and appropriate at the tertiary level. In addition, we recommend the process of CoRe+ completion as a means of professional development for tertiary chemistry educators, because we observed that participation in this process led to an increase of educators’ awareness of PCK, hence generating useful TSPK for both participants and the community.

A key finding was that the majority of participants had developed their PCK through their own teaching experiences and awareness of their own students’ outcomes, filtered by their individual beliefs and backgrounds. Therefore the TSPK for this community has been built through practice rather than professional development. This study thus reinforced the elements of the consensus model, since this finding supports the flow of TSPK upwards as well as downwards.

We found that tertiary chemistry teachers integrate their TSPK strategies in parallel ways to those used by secondary teachers, in particular the use of analogies and metaphors, awareness of problematic concepts and use of representations (such as carefully selected demonstrations). The teaching strategies cited in this project corresponded with recognised secondary teaching strategies in science education (Gabel, 2003; Treagust, 2007). This supports the finding that the tertiary teachers’ beliefs, goals and practices align with established PCK frameworks (Fraser, 2016).

While a wide range of strategies is used by tertiary teachers and the strategies are selected based on fit to the specific content being taught, there is an absence of strategies derived from professional teacher training. This may point to missing discipline specialisation in professional development for tertiary teachers. In addition, strategies adopted to check student understanding tend to be labour-intensive and therefore difficult to apply on the large scale of some undergraduate classes. Increased knowledge and skill in the area of peer assessment and the application of technology to accelerate feedback to students is called for to reduce this barrier to effective teaching.

The ChemPCK website gives a starting point for tertiary chemistry teachers to improve their teaching based on tested strategies that work for others in similar situations. The use of the website along with informal feedback from both workshop participants and others who have accessed the website indicate that this is an effective method of sharing TSPK between generations of university teachers.

Conflicts of interest

There are no conflicts to declare.

Acknowledgements

We are grateful to all participants in the workshops who generously shared their expertise and time. We also thank our reference group of John Loughran, Roy Tasker and Bob Bucat. Support for this project was provided by the Australian Government Office for Learning and Teaching (SD14-3737). The views in this manuscript do not necessarily reflect the views of the Australian Government Office for Learning and Teaching. We also gratefully acknowledge the helpful input of the reviewers.

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