Developing Pre-Service Teachers’ Pedagogical Content Knowledge: Lessons from a Science Methods Class

Abstract

A citizen’s ability to thrive in today’s technologically advanced society necessitates robust and nimble scientific literacy. The development of such literacy is rooted in science instruction that engages students with appropriate cognitive tools that enable active knowledge construction through scientific practices. One such instructional approach with proven positive science learning outcomes is project-based learning. However, little is known about future teachers’ takeaways from participation in project-based learning science methods courses and how those takeaways connect to teachers’ developing pedagogical content knowledge. In this qualitative study, we examined pre-service teachers’ end-of-semester reflective blogs and identified the main themes and connections to the five dimensions of pedagogical content knowledge (PCK). Across three cohorts of pre-service science teachers, we found nine common themes connected to the four dimensions of PCK that involve teachers’ orientations towards science teaching, their knowledge of science curricula, instructional strategies, and students’ understanding of science. We found no prominent connections to the dimension that emphasizes a teacher’s knowledge of the scientific literacy assessment. These findings suggest the asymmetrical development of pre-service teachers’ PCK. Teacher educators should explicitly address the scientific literacy assessment and support pre-service teachers as they develop their knowledge of it. We discuss additional implications for research and practice.

1. Introduction

Despite a recent increase in anti-science rhetoric in some spheres of society, authors of educational reform documents, as well as science educators, accept that scientific literacy is a prerequisite for successful engagement with today’s technologically and scientifically advanced society (National Research Council, 2012). The development of scientifically literate young people has been one of the longstanding goals of science education. However, educating such a scientifically literate population requires instructional approaches that engage students in active problem solving and result in the deep understanding of important scientific concepts.

Project-based learning (PBL) is one such constructivist approach where students actively build their knowledge through working with scientific ideas in authentic contexts to solve real-life problems (Krajcik & Shin, 2014). Krajcik and Shin (2014) emphasized that PBL environments are characterized by the following six features: (a) a driving question; (b) a focus on learning goals; (c) students’ engagement in scientific practices; (d) collaboration; (e) the use of technology to scaffold learning; and (f) the creation of tangible artifacts that address the driving question. In PBL in science, students solve authentic problems that are important to them using approaches and processes similar to those of real scientists. Thus, the doing of science translates into participation in scientific and engineering practices (Krajcik & Shin, 2014).

A significant body of research has focused on how to apply PBL in schools, demonstrating its positive impact on students’ learning outcomes (Blumenfeld et al., 1991; Geier et al., 2008; Marx et al., 2004; Rivet & Krajcik, 2008). However, less is known about the impact that participation in a semester-long PBL-based science methods course may have on pre-service teachers’ (PSTs’) learning of PBL as an instructional approach in addition to the development of their pedagogical content knowledge (PCK). With our study, we contribute to the knowledge about PST conceptualizations of PBL after engagement in one such PBL-based science methods course. We also consider how those experiences may be impacting PSTs’ developing PCK, in turn informing the PSTs’ future pedagogical practice. The following research questions (RQs) framed our study:

RQ 1: What aspects of the PBL experience within a science methods course emerged as themes in PSTs’ reflections and blogs?

RQ 2: How do (or do not) the emergent themes from PSTs’ blogs and reflections on PBL connect (or do not connect) to the components of PCK for science teaching?

2. Literature Review

2.1. Project-Based Learning (PBL)

Stemming from the works of John Dewey, modern PBL draws on findings from the learning sciences for its four theoretical pillars—(a) active construction, (b) situated learning, (c) social interaction, and (d) cognitive tools (Krajcik & Shin, 2014). In science education, these pillars provide support for the development of deeper knowledge as learners actively and collaboratively construct their joint understanding of scientific phenomena and practices while they investigate authentic issues rooted in students’ daily lives (Blumenfeld et al., 1991; Marx et al., 1997). PBL forefronts the situated nature of learning; learners function as active agents, participating in multiple, overlapping, and sometimes even contradicting communities of learning (Collins & Kapur, 2022; Krajcik & Shin, 2014). Each learner brings to the learning environment a different history and knowledge and is able to make unique contributions to the building of the joint understanding (Greeno & Engeström, 2014).

Science knowledge construction is a social and collaborative engagement fueled by diverse perspectives (Driver et al., 2000). In PBL, science, as a social practice, unfolds through collaborative work on a systemic scientific inquiry, affording students opportunities to investigate scientific phenomena, discuss their current knowledge, collect and analyze relevant data, construct and revise their understanding, and engage in communicating their findings to others through jointly created artifacts (Gillies & Nichols, 2015; Krajcik & Shin, 2014; Tal et al., 2006). Learners’ engagement in a high-quality dialogic discourse that includes prompting for clarifications, elaborations, and reasoning about science phenomena promotes the development of higher-order cognitive skills of evaluation and the synthesis of knowledge (Duschl & Osborne, 2002; Gillies et al., 2014).

Learners’ engagement with the PBL task and content is mediated through cognitive tools that help learners connect prior knowledge to the current project; plan their investigations; collect, organize, and visualize data; collaborate more productively; and report their findings (Novak & Krajcik, 2006; Tal et al., 2006). Students engaged in long-term investigations of meaningful questions create, revise, and interconnect multiple representations of the phenomena, thus building a deeper and integrated understanding of scientific concepts (Kozma et al., 2000; Novak & Krajcik, 2006; Singer et al., 2000). Student-created artifacts, often in the form of hypermedia reports, present opportunities for teachers to assess students’ understanding of the science practices and content and to provide constructive feedback that leads to consequential revisions and fosters the building of deep knowledge (Novak & Krajcik, 2006; Singer et al., 2000). The affordances of rapidly evolving digital technologies continuously move the frontier of possible support during collaborative inquiry in science classrooms, while also increasing the complexity faced by teachers as orchestrators of and collaborators in PBL.

Successfully orchestrating, implementing, and supporting multifaceted student-centered scientific inquiry is challenging for many teachers as it requires a shift in teachers’ pedagogical practice and beliefs about teaching and learning (Blumenfeld et al., 1991; Fives et al., 2015; Marx et al., 1997). Although science teachers self-reported high levels of inquiry-based teaching (Blanchard et al., 2013; Capps & Crawford, 2013; Capps et al., 2016), a closer review of their practice revealed that their knowledge of science inquiry was not well-structured (Capps et al., 2016) and there was little evidence of inquiry in teachers’ observed pedagogical practice (Capps & Crawford, 2013). These findings resonate with concerns expressed by Chinn and Malhotra (2002), who compared inquiry in K-12 science classrooms with the authentic inquiry performed by real scientists. They found that school-based inquiry led to students thinking in a manner that was simple, algorithmic, and certain. On the other hand, science teachers who successfully implemented inquiry-based activities emphasized student agency and supported students’ execution of their own investigations through collaborative activities, argumentation, and the exchange of ideas, which results in higher student learning gains (e.g., Fogleman et al., 2011; McNeill et al., 2013; Tal et al., 2006). Recent studies have demonstrated that participation in PBL courses and inquiry activities helps PSTs to develop the necessary understanding of science and pedagogical knowledge for authentic science instruction, as well as their abilities for reflection, collaboration and, research (Connolly et al., 2023; Khaokhajorn & Srisawasdi, 2024; C. C. Wang, 2021). Given the demonstrated potential of PBL in science to produce higher knowledge gains for all students (Marx et al., 2004; Rivet & Krajcik, 2008), to reduce the achievement gap (Geier et al., 2008; J. C. Marshall & Alston, 2014), and to foster PSTs’ professional development (Connolly et al., 2023; C. C. Wang, 2021), it is of critical importance that science teachers become proficient at enacting PBL. To realize this vision of science learning, the development of teachers’ knowledge for enacting effective PBL needs to be systemically fostered and supported. However, we concur with Hanuscin et al. (2018) that taking an empathetic, rather than a deficit, view of novice teachers and their developing pedagogical expertise is a more productive approach for providing them with comprehensive and coherent support.

2.2. Pedagogical Content Knowledge

Shulman (1987) conceptualized PCK as “the special amalgam of content and pedagogy” (p. 8), characterized by “an understanding of how particular topics, problems, and issues are organized, represented, and adapted to the diverse interests and abilities of learners, and presented for instruction” (Shulman, 1987, p. 8). Shulman emphasized the evolving nature of the knowledge base for teaching, anticipating changes that will be revealed by the future advancements in the theory and practice of teacher education and teaching. Indeed, researchers have posited various models of PCK for science teaching (e.g., Gess-Newsome, 2015; Grossman, 1990; Loughran et al., 2004; Magnusson et al., 1999; Park & Oliver, 2008). Some models (e.g., Grossman, 1990; Magnusson et al., 1999) draw on the work of Shulman (1986, 1987), who distinguished between seven categories of teachers’ knowledge, as follows: (a) subject matter content knowledge (SMK); (b) PCK; (c) curricular knowledge; (d) general pedagogical knowledge; (e) knowledge of students; (f) knowledge of educational contexts; and (g) knowledge of educational aims and values, as well as their philosophical and historical bases. These models, in which PCK is separate from SMK, can be thought of as transformative models (Kind, 2009). Other models, which include SMK within PCK, are called integrative models (Kind, 2009). The main critique of integrative models is that they lack explanatory power to explicate the mechanisms through which PCK develops because the categories of teachers’ knowledge, as well as their interactions with each other and the context in which teaching happens, remain obscured (Abd-El-Khalick, 2006; Kind, 2009). Thus, transformative models which allow for an examination of different categories of teachers’ knowledge are more effective for explaining the development of teachers’ PCK and the factors that affect it.

The majority of the researchers who have studied the development of science teachers’ PCK have relied on a transformative model by Magnusson et al. (1999); (e.g., Cohen & Yarden, 2009; Demirdöğen, 2016; Park & Chen, 2012), although other representations have also been used (Davidowitz & Rollnick, 2011; Nilsson & Loughran, 2012). We conceptualized our study using Magnusson and colleagues’ model of PCK for science teaching as our framework for interpreting and discussing how PSTs’ understanding of PBL after participation in a semester-long PBL-based science methods course connects to the dimensions of PCK.

In the Magnusson et al. model, there are five distinct components of PCK, as follows:

• Orientations towards science teaching: This component includes “teachers’ knowledge and beliefs about the purpose and goals for science teaching at a particular grade level” (p. 97) and guides teachers’ instructional decisions.
• Knowledge of science curricula: This component encompasses knowledge of national-, state-, district-, and school-mandated goals and objectives for students’ learning for the current grade, as well as across the grades (i.e., knowledge of vertical curriculum). This component also includes knowledge of specific curricular programs and materials for specific subjects.
• Knowledge of students’ understanding of science: This component comprises knowledge about the requirements for learning about specific scientific concepts and knowledge about areas of science that students find difficult to understand.
• Knowledge of instructional strategies: This component includes knowledge of subject-specific and topic-specific strategies.
• Knowledge of assessment of scientific literacy: This component includes knowledge of the dimensions of science learning that are important to assess and knowledge of the methods by which that learning can be assessed.

In this paper, we relied on the components of PCK as conceptualized by Magnusson et al., including the construct of the knowledge of assessment of scientific literacy. However, we briefly point out that the term scientific literacy itself has no agreed-upon definition in the literature, although most definitions encompass students’ knowledge and understanding of science concepts and the ability to use them to evaluate claims and make evidence-based decisions about the world around them (Klebel & Kormann, 2024; Shaffer et al., 2019).

Well-developed PCK is of critical importance for a teacher’s ability to orchestrate effective science instruction. The current focus on scientific practices and the realization of the Next Generation Science Standards’ (NGSS; NGSS Lead States, 2013) vision of science education necessitates that teachers develop “new knowledge of the ideas and practices in the disciplines of science, an understanding of instructional strategies that are consistent with the NGSS vision, and the skill to implement those strategies in their classrooms” (National Research Council, 2015, p. 2). Consistent with the science teachers’ knowledge called for by the National Research Council (2015), Gess-Newsome (2015) defined PCK as “both a knowledge base used in planning for and the delivery of topic-specific instruction in a very specific classroom context, and as a skill when involved in the act of teaching” (pp. 31–32). Gess-Newsome distinguished between teachers’ personal PCK (i.e., reflection on action) and PCK and skill, which becomes manifested in the act of teaching (i.e., reflection in action).

2.3. Development of Teachers’ Pedagogical Content Knowledge

The development of teachers’ PCK is a complex process that blends subject-matter knowledge and a pedagogical understanding of how to facilitate student comprehension (Magnusson et al., 1999). Teaching experience is consistently identified as a major source for the development of a teacher’s PCK (Wongsopawiro et al., 2017). Consequently, pre-service and novice teachers have limited PCK due to their nascent practical experience. Key drivers of PCK growth and development bridge the theory–practice gap by immersing teachers in authentic classroom situations and complexities, including practical application through PBL and experiential tasks (Atay et al., 2010; Erviana et al., 2022). A strong content knowledge serves as another prerequisite that can accelerate PCK growth by enabling teachers to better analyze students’ thinking and address misconceptions (Li & Copur-Gencturk, 2024). Reflective practices, such as self-study, critical incident analysis, and the systemic analysis of students’ work, are crucial for making tacit PCK explicit and for generating new insights (Cite et al., 2017; Hanuscin & Hian, 2009; Wongsopawiro et al., 2017).

Despite the consensus within the field on the key drivers of PCK development, there are also some nuanced and occasionally contradictory findings. A notable debate exists regarding the effectiveness of self-directed learning through teaching versus the necessity of explicit external guidance and support. While some researchers highlighted the limitations of the unguided experience and the critical need for well-structured interventions such as mentoring and action research (Bektas, 2015; Oztay et al., 2023; Wongsopawiro et al., 2017), others indicated that PCK growth can occur autonomously (Li & Copur-Gencturk, 2024). Wongsopawiro et al. (2017) found that literature reviews fostered the development of teachers’ knowledge of assessment. Yet, formal coursework, while providing pre-service teachers with the initial confidence and foundational knowledge, is often insufficient for developing the practical instructional and assessment skills required for student-centered teaching (Sizer et al., 2021; Bektas, 2015). Moreover, PCK development is idiosyncratic, varying significantly across individuals even in similar learning environments (Oztay et al., 2023; Wongsopawiro et al., 2017). A further challenge lies in translating the expressed confidence in innovative pedagogies into actual classroom practices, which require teachers to give up some control and allow time and space for student-guided learning (Dragnić-Cindrić et al., 2024); as such, teachers may revert to more familiar, teacher-centered approaches, rather than engaging in “acts of rebellion” against traditional school cultures (Hanuscin & Hian, 2009, p. 1; Sizer et al., 2021). To further situate our study and its findings, in the following section, we review the literature on the role of blogging in the development of teachers’ reflexivity and PSTs’ development from students into teachers.

2.4. Developing Reflective Science Teachers in the 21st Century

Reflective practice is one of the hallmarks of effective professionals (Killeavy & Moloney, 2010; Schön, 1987; Turvey & Hayler, 2017). Expert professionals integrate on-the-spot reflection-in-action into a smooth execution of their current task, while addressing the uniqueness of the situation, with its uncertainties and value conflicts (Schön, 1987). Helping novice teachers become reflective practitioners means gradually developing their capacity for skillful reflection-in-action, as well as for reflection-on-action and on the written reflections themselves (Gess-Newsome, 2015; Schön, 1987).

Moreover, PSTs should be able to articulate good educational rationale for their pedagogical practices (Liston & Zeichner, 1990). A prerequisite for such an explanation is PSTs’ understanding of their own social and cultural beliefs, schools, and surrounding communities, as well as the aims and values of distinct educational traditions (Liston & Zeichner, 1990). Empirical studies suggest that personal and private PSTs’ reflective accounts help PSTs voice and explicate their emerging pedagogical knowledge (e.g., Berry & Loughran, 2010; Clarke, 2003; Parker & Heywood, 2013). Furthermore, deep critical reflections and examinations of past teaching and learning experiences serve to shape new teachers’ future actions as they begin to either affirm or challenge their apprenticeship of observation (Boyd et al., 2013; Killeavy & Moloney, 2010; Schön, 1987) and situate themselves among and within educational traditions (Liston & Zeichner, 1990). Reflective practice enables PSTs to recognize their strengths and weaknesses and identify topics they want to learn more about and improve upon (Kewalramani et al., 2025; Maharjan et al., 2024). Thus, reflection evolves into reflectivity when PSTs’ intentional internal dialog results in the transformation of their beliefs, expectations, and, ultimately, their pedagogical practices (Feucht et al., 2017).

Wall and Anderson (2015) noted that the proliferation of mobile technologies led to a paradigmatic shift towards participatory culture, influencing PSTs’ readiness to use social media, such as blogs, during their academic training. A blog is a personal online space through which an author publishes posts, shares resources, and engages in dialog with others interested in similar topics (Luehmann, 2008). We expand this definition to include dynamic environments shared by groups of people (e.g., the whole class), on platforms such as Edmodo, which forefront the social aspects of blogging. Blogs move reflection from the private sphere to the public and social spheres, allowing the discussion to continue beyond the face-to-face classroom interactions, thus removing the constraints of institutional space and time (Hall, 2018; Wall et al., 2014; Yang, 2009). As Wood (2012) illuminated, blogs exist as an in-between or “liminal space” (p. 89) in which students can start becoming teachers, engaging in reflection and inquiry, free of the traditional hierarchy of the classroom, while they navigate from one state to another.

A significant body of research focuses on affordances of blogging for the development of teacher identities (e.g., Luehmann, 2008; Wall & Anderson, 2015; Wood, 2012) and communities of practice among newcomers into the teaching profession (e.g., Anderson et al., 2013; Killeavy & Moloney, 2010; Yang, 2009). Previous research on the effectiveness of blogging as a tool for reflection suggests that most PSTs use blogs to engage in simple affirmations and descriptions of their experiences (Anderson et al., 2013; Killeavy & Moloney, 2010; Yang, 2009), unless provided by a supporting framework that facilitates critical reflection on pedagogical practice (Hall, 2018). PSTs who make their learning public through blogging are able to wrestle with the essential issues of science teaching and learning in established contexts, collaborating and exchanging ideas within a community of their peers (Bataller-Català, 2025; Childs, 2021; Wall et al., 2014). Blogging was shown to be effective for building PSTs’ reflective skills and for advancing their self-efficacy for teaching and their professional development (Bataller-Català, 2025; Cirak Kurt & Yildirim, 2021). A combination of blogs, coursework, and observations leads students to begin to challenge the apprenticeship of observation and contemplate their position as teachers, as well as the possibilities of pedagogical practice and the needs of their students (Boyd et al., 2013).

In summary, the empirical evidence presented in this literature review seems to indicate a synergistic relationship between reflective practice, PBL, and the development of PSTs’ PCK. Reflective practice enables crucial cognitive and metacognitive processes though which engagement in authentic learning contexts such as PBL is transformed into refined pedagogical understanding. PBL, in turn, provides the necessary rich, real-world application environment for PSTs to integrate their PCK and to hone the essential 21st century skills. In this study, we focused on PSTs’ emerging personal PCK, as evidenced in their reflections on and reasoning about PBL posted on the class blog site. Our study contributes to the literature by exploring what aspects of PBL are easily accessible and salient to PSTs after their participation in a PBL-based science methods course. By examining the blogs of future teachers across three different cohorts for common themes and their connections to the components of PCK for science teaching, we aim to illuminate the trends in the development of PSTs’ personal PCK at the end point of their teacher preparation program. The use of blogs as a communal space for individual reflection enabled us to contribute to the broadening of the understanding of PSTs’ private knowledge as they shared it with their peers.

3. Materials and Methods

3.1. Design-Based Research

We used design-based research (DBR) as our enveloping methodological framework, which was extended from our larger federally funded study. DBR unfolds over time through an iterative process, during which the theory and solutions to practical problems develop simultaneously, informing each other (McKenney & Reeves, 2012; Easterday et al., 2014; Brown, 1992). In this study, we adopted a six-phase DBR model, as was put forth by Easterday et al. (2014).

The six phases in this model are focus, understand, define, conceive, build, and test (Easterday et al., 2014). The first three phases of DBR are dedicated to the focusing and defining of the project scope, the understanding of the audience, the context, the relevant domains and already-existing solutions, and the defining of the specific goals for the current project. The next three phases center on the ideation, building, and testing and evaluation of the solution. DBR phases do not happen sequentially, but in rapid iterations, containing nested scientific processes as sub-phases of design (Easterday et al., 2014).

These key characteristics of DBR are fully evident in the present study. We tested the PBL-based Bio-Sphere curriculum with PSTs. We evaluated the ways in which the PSTs interacted with the curriculum over the course of the semester and how the curriculum served to foster the development of PSTs’ emergent PCK. We will discuss how the findings from this study will inform subsequent design changes to Bio-Sphere curriculum materials.

3.2. Content Analysis

In this study, we employed conventional content analysis as our research method for the analysis of PSTs’ blogs in which they reflected on PBL (Hsieh & Shannon, 2005). C. Marshall and Rossman (2016) pointed out that content analysis evolved from being viewed as a way to quantitatively describe the content of a text by counting the appearances of certain words or expressions into a sophisticated method that enables researchers to describe and interpret the written products of social groups or even a whole society. As we seek to build a deeper understanding of PSTs’ development of PCK for science teaching, content analysis fits with our research aims of illuminating the aspects of PBL that were most salient for PSTs after a semester-long PBL-based science methods course, as well as the connections of those emergent main themes to the components of PCK.

Consistent with the approach used in conventional content analysis, we avoided using preconceived codes and categories and allowed them to emerge from our data, thus gaining information directly from our study participants (Hsieh & Shannon, 2005). The inductive coding of manifest (i.e., literally present in the text) and latent (i.e., implied meaning) content enabled us to capture all of the participants’ ideas and then consolidate our codes into categories, while still discerning those that we believed to be different (Kondracki et al., 2002).

3.3. Study Context and Participants

We carried out our study in a PBL-based science methods class for elementary PSTs at a large research university in southeastern United States. As part of the class, PSTs took part in Bio-Sphere curriculum, a life sciences curriculum focused on local sustainability issues in which students engage in PBL tasks through inquiry activities. This curriculum has been developed as a part of a large, federally funded DBR project that is a collaborative effort between several research universities.

A total of 57 students participated in this study (100% female) from three consecutive cohorts of elementary PSTs in a PBL-based science methods course (see

Table 1. Number of participants per cohort and demographic information.

	Y1 *	Y2	Y3
Number of participants	28	24	5
Gender
Female	100%	100%	100%
Age (mean)	-	21.04	23
Highest level of education completed so far
Four-year college	-	-	100%
Two-year college	-	4.17%	-
High school	-	95.83%	-

* Note: Detailed demographic information was not collected in Y1.

). In year 1 (Y1) and year 2 (Y2), our course was a part of the undergraduate program in elementary- and middle-grade education. In year 3 (Y3), the teacher education program transitioned from the undergraduate to the graduate level teacher preparation program. Because of this transition, course enrollment in Y3 was atypically low, with only 5 enrolled students.

Students were solicited for voluntary participation in the study by a member of our research team using the recruitment protocol approved by the Institutional Review Board (IRB). All participants signed an informed adult consent form approved by the IRB. In Y2 and Y3, we collected additional demographic information about students’ age, education level thus far, and year in the current program. The teacher preparation program’s transition from undergraduate to graduate level explains the difference in participants’ levels of education and the age of participants in Y2 and Y3. No participants had any prior teaching experience, except for one student in Y3, who had approximately two years of experience as a high school teacher.

3.4. Science Methods Course

3.4.1. Course Design

Our PBL-based science methods course was designed and taught by the second author. The students participated in a range of inquiry activities, from open-ended to guided activities (Kang & Keinonen, 2018; Sadeh & Zion, 2009). PSTs experienced these inquiries both as students and as novice science teachers, through two student-teaching experiences in the 2nd and 5th grade in local elementary schools. As part of the course, PSTs also developed lesson plans, critically evaluated commercially available curricular materials selected by the course instructor, and wrote eight blog posts as reflections.

3.4.2. Bio-Sphere Curriculum

Bio-Sphere curriculum is an eight-week-long, project-based, technology-supported science curriculum. Compost, a collaborative life sciences curricular unit is focused on issues of sustainability, energy, and matter and is suitable for implementation in under-resourced schools in rural areas of the United States. Because Bio-Sphere curriculum is grounded in collaborative meaning making, PSTs in our class worked in small groups based on their grade level focus. Students built, collected data on, analyzed, and modified a compost bio-reactor in order to develop compost that decomposes quickly and has no odor. Working in small groups, students utilized computer simulations to run tests on virtual compost piles, optimized composting conditions, and collected secondary inquiry information via an online reference tool. The curriculum utilizes projects that provide the students with experiences about decomposition, waste, ecosystems, the cycling of matter, and the flow of energy. The whole class also visited a community garden with a well-established composting operation.

3.5. Data Sources

Data collected in the broader study included small-group and whole-classroom videos, field observation notes, and students’ written artifacts in the form of science notebooks, group posters, and student blog posts. During the semester, PSTs responded to a total of eight blog prompts that incorporated reflections on both PBL- and field-based teaching experiences (see

Table 2. Reflective blogs through the semester.

Blog Title	Blog Type	Task Description
Science autobiography	Autobiography	Reflect on early in-school and out-of-school learning experiences that have shaped your current views of science.
What is science?	Photovoice presentation	Capture, describe, and reflect on science in everyday life.
What can or cannot be composted?	PBL reflection	Based on the trash sort activity completed in class, form an evidence-supported claim about what can and cannot be composted.
Visit to the community garden reflection	PBL reflection	Reflect on the class visit to the community garden that provides food for low-wage workers.
Making a bioreactor: hypothesis reflection	PBL reflection	Reflect on the initial compost hypothesis, evidence, counter evidence, claim, and reasoning.
Reflection on 2nd-grade field teaching experience	Field teaching reflection	Reflect on the lower elementary grades field teaching experience.
Reflection on 5th-grade field teaching experience	Field teaching reflection	Reflect on the upper elementary grades field teaching experience.
Reflection on PBL experience	PBL reflection	Reflect on what elements of PBL are necessary for a successful project learning experience.

). For this study, we focused on the final blog, in which PSTs reflected on PBL.

3.6. Data Analysis

We identified a total of 53 complete data sets—26 in Y1, 22 in Y2, and 5 in Y3. We considered a data set to be complete if a student completed more than half of the assigned blogs and if they completed their PBL blog. Using an inductive approach (Thomas, 2006), we started our analysis by immersing ourselves in data by reading all of the PSTs’ blogs to obtain a sense of their science background and their journey through the science methods course. In total, we read 160 blogs for Y1, 163 blogs for Y2, and 40 for Y3. We then proceeded through a second reading, in which we focused on the PBL reflection blogs, highlighting words and expressions that seemed to reflect the key concepts, thoughts, and feelings of PSTs towards PBL. We sorted the emergent codes into categories (i.e., themes) based on how they were related. Through peer debriefings and discussion, we identified initial themes and then used them to independently code 20% of randomly selected blogs (Hodson, 1999). Upon completion of the coding and achieving 82% agreement, we met to review and resolve our differences in coding through discussion until we achieved 100% agreement. The first author then proceeded to code the rest of the data.

To ensure that we were adequately capturing participants’ ideas, we coded data at the sentence level using NvivoPro11 software. Because it is possible for one sentence to carry multiple ideas, the same sentence could receive multiple, mutually exclusive codes. For example, the sentence “The benefit of PBL in the classroom is more authentic learning and opportunity for deeper exploration and questioning,” received two codes—PBL as authentic learning and PBL allows for deeper exploration. During the analysis, some subcategories emerged, enabling a more precise consolidation of the codes and the preservation of participants’ ideas. We determined the main themes based on the frequency of their appearance in the blogs (

Table 3. Common themes across three cohorts—examples from students’ blogs.

Theme	Example
Learner agency in PBL	“They are student-driven, giving lots of voice and choice to students to lead their learning and find solutions for themselves.”
Cost of PBL implementation	“As teachers, time is very limited because of the numerous standards and testing that has to take place during the year.”
PBL as an authentic learning experience	“The benefit of PBL in the classroom is more authentic learning and opportunity for deeper exploration and questioning.”
PBL as an instructional approach	“I really like how I can always modify or adapt a problem/inquiry in order to fit the needs of the class.”
PBL as a hands-on activity	“Project-based learning is a great way to get hands on and visual experience with a topic.”
PBL as an instructional approach	“PBL also allows us to learn more about our students and their funds of knowledge.”
A teacher’s role in PBL	“…in order for project-based learning to be successful the teacher must act as a coach, encouraging the students but not feeding them the answers.”
PBL develops desired skills	“Throughout the process, students will learn to work with others, solve problems, and communicate effectively which are skills needed to succeed in today’s society.”
PBL differs from traditional school instruction	“In a traditional classroom, students are asked to sit at their desk/table and complete worksheets on a subject, or to sit and copy notes down.”
PSTs’ emotions towards PBL instruction	“I thoroughly enjoy engaging in project-based learning as an adult and know that students also enjoy it.”

).

4. Results

4.1. Main Common Themes Across Cohorts

Through our content analysis, we identified nine dominant themes that were common to all three cohorts—(a) learner agency in PBL; (b) cost of PBL implementation; (c) PBL as an authentic learning experience; (d) PBL as a hands-on activity; (e) affordances/limitations of PBL as an instructional approach; (f) a teacher’s role in PBL; (g) PBL develops desired skills; (h) PBL differs from traditional school instruction; and (i) PSTs’ emotions towards PBL instruction (see Table 3 and

Table 4. Frequency of references to dominant themes.

		Participants Referencing the Theme
Theme	References	Number	%
Learner agency in PBL	176	51	96.23%
Cost of PBL implementation	150	43	81.13%
PBL as an authentic learning experience	101	39	73.58%
PBL as a hands-on activity	50	38	71.70%
Affordances/limitations of PBL as an instructional approach	54	31	58.49%
A teacher’s role in PBL	44	20	37.74%
PBL develops desired skills	47	16	30.19%
PBL differs from traditional school instruction	36	22	41.51%
PSTs’ emotions towards PBL instruction	35	24	45.28%

). More than 30% of the study participants reflected on each of these themes, generating a total of 693 references.

4.1.1. Learner Agency in PBL

Learner agency in PBL emerged as the theme with the highest frequency of references in all three years (Table 4). PSTs reflected on the agentic nature of PBL by referring to both their own experiences as learners in our PBL-based science methods class and their views as novice teachers regarding their students’ agency in PBL. For example, Tracy (all names are pseudonyms) wrote the following:

“In our own class, I really appreciate the way we went about creating our bioreactors because we all were able to assemble the contents of our compost system the way we thought would work best and had a lot of freedom in how we did that.”

Tracy’s post is representative of PST reflections on their own experiences as active participants in PBL who were in control of their own learning. Another PST—Kelly—reflected on students’ agency, stating the following: “When students are given the opportunity to participate in project-based learning, they are guiding their own learning and exploring the many concepts of the given topic on their own terms.” Reflecting on PBL from two perspectives—as a student and as a teacher—served as a PST’s departure point for evolving from their role as a student towards their new role as educators. We found similar examples of dual perspectives in each of the main themes.

4.1.2. Cost of PBL Implementation

The second theme, cost of PBL implementation, captured a variety of costs that PSTs identified as being related to the implementation of PBL, ranging from monetary expenses, the costs of supplies, and the additional work PBL drives for the teacher to the costs in terms of the negative impact on the relationship with the school administration and parents who may not be supportive of PBL. However, the majority of PSTs reflected on time as being the key cost and detriment to the successful implementation of PBL. PSTs emphasized two different aspects of time limitation that might impact a science teacher’s ability to implement PBL—(a) insufficient time devoted to elementary science education due to the focus on literacy and mathematics, and (b) short time allotted to the specific science topics within the science curriculum.

The following two posts exemplify novice teachers’ awareness of the lack of time available for PBL due to the place of science education in elementary education. Rebekah wrote the following: “Science is definitely put on the back burner in most schools, and this type of project-based learning takes a lot of time each day across multiple days to complete.” PSTs were also aware of the incongruence of the brisk pacing of the science curriculum, as dictated by the school districts, and meaningful science projects that might require a long time to carry out. Linda wrote the following: “Some of these projects may take weeks at a time and most schools have to follow a specific pacing guide, even with their science curriculum.” This finding indicates future teachers’ emerging awareness of external, systemic barriers that shape the pedagogic practice of individual teachers.

4.1.3. PBL as an Authentic Learning Experience

The third theme, PBL as an authentic learning experience, encapsulates PSTs’ reflections on the situated nature of PBL and the relevance of the projects to the daily lives of students and their communities. In contemplating the importance of having authentic problems to solve through PBL, PSTs once again drew on their experiences as students and as novice teachers. Lilly wrote the following:

“One way you made this compost project relevant to me this semester is through the field trip to the community garden here on campus… This helped me to understand why we were doing this unit and learning about composting. At this moment it became real and relevant to me.”

Reflecting on the authenticity of the projects, Mia wrote the following, from the perspective of a novice teacher: “I believe that this can be achieved by choosing topics that are relative to students’ lives (for example, water quality in our community), or by choosing topics based on things students have shown interest in the past.” The PSTs in this study interpreted project authenticity as a proxy for the relevance of the projects to the students’ communities and daily lives. They did not articulate a deeper understanding of project authenticity as a requirement for the project to be an approximation of the scientific practices that are developmentally appropriate for their students. Whereas the personal relevance of the project for the students might serve to trigger and sustain students’ interest in the project, students’ science learning is connected to their engagement in authentic practices of science. Based upon this data, the PSTs in our course have not made that connection.

4.1.4. PBL Is a Hands-On Activity

It is important to point out that many of the PSTs made references about PBL as an authentic learning experience while also explaining that PBL is hands-on activity, which is the fourth common theme. The two themes differ in their emphasis. Whereas the former emphasized the authenticity of the problems and experience, the latter put emphasis on activity and the simple performance of this activity. Many of the PSTs referenced the two themes in the same sentence, causing us to question if when faced with the pressures of the daily pedagogical practice in the elementary school classroom, PSTs might resort to the superficial application of hands-on activities to facilitate the learning of science. This view of PBL as a hands-on activity is present in Kate’s reflection, as follows: “Additionally, for project-based learning, it is necessary that the activities are hands-on and allow students to make real-world connections.” Combined with the PSTs’ conceptualization of project authenticity as being equivalent to the relevance of the project for the students and their communities, the focus on hands-on activities further strengthens our conclusion that PSTs’ initial conceptualization of PBL might reflect a focus on the superficial aspects of PBL as a method for the teaching and learning of science.

4.1.5. PBL as an Instructional Approach

The theme of PBL as an instructional approach comprises PSTs’ reflections on the affordances and limitations of PBL for the teacher. Taking the perspective of new teachers, the PSTs in our science methods class noted that PBL allows them to gain an insight into the students’ ways of thinking and their existing knowledge funds. This is exemplified in Maria’s statement, as follows: “PBL also allows us to learn more about our students and their funds of knowledge.” The PSTs appreciated the adaptability of the projects to the different grade levels and needs of the class. For example, Jane noted the following: “I really like how I can always modify or adapt a problem/inquiry in order to fit the needs of the class.”

As one of the pedagogical challenges, the PSTs noticed the inherent variability and uncertainty in the outcomes of PBL. Kay wrote the following: “Also, educators may never know what the final result/product will be as a lot of it is dependent upon the students and what they come up with.” As they grappled with the place of uncertainty in science teaching and learning, some PSTs reflected on their own learning in our class and emphasized the value of learning from failure. Tracy stated the following: “Additionally, because we did not receive explicit instructions about how our compost should be created, it allowed for diversity of results within the class and the opportunity for failure.” However, other PSTs expressed the need to be more involved in order to ensure the desired learning outcomes. Lilly expressed a concern about students’ learning, as follows: “We also have to evaluate on the fly if the direction a student is going will be one that allows that student to reach the learning goals.” Tamara suggested employing direct instruction to address uncertainty, as follows: “Obviously there will be times when explicit instruction is needed in more difficult projects, however, I think that this should be minimized and student exploration encouraged.” PSTs’ recognition of the inherent uncertainty present during scientific inquiry led them to consider trade-offs between permitting for more student agency and for maintaining teacher control during investigations. Although some PSTs embraced the opportunity for students to learn from failure, others expressed the need to revert back to teacher-centered instruction as a way to control the uncertainty of the inquiry outcomes and to ensure the achievement of the learning goals.

4.1.6. A Teacher’s Role in PBL

The theme of a teacher’s role in PBL captured PSTs’ understanding of the role of the teacher as a guide and co-learner in PBL, who stays flexible and responsive to the needs of the students while maintaining an awareness of targeted science standards and learning goals. Anne emphasized the following: “Teachers must be willing to work and learn alongside students in project-based learning, and must be flexible with time and space so that students have the ability to explore the scientific concepts on which the project-based learning focuses.” As illustrated by the following statement by Leona, PSTs reflected on the role of the teacher as a coach or guide in PBL: “…in order for project-based learning to be successful the teacher must act as a coach, encouraging the students but not feeding them the answers.”

This theme indicates that future teachers are aware that the implementation of PBL necessitates an adjustment from the role of the teacher as the knowledge authority to the role of the teacher as a guide in inquiry. In their reflections, PSTs started to challenge the traditional teacher-centered pedagogical practices that dominated their own school experiences. They began to evolve their own science teaching orientations toward project-based and inquiry-focused orientations and away from process and didactic orientations (Magnusson et al., 1999). Within this theme, PSTs also demonstrated an understanding that appropriate time, space, and scaffolding need to be provided to the students to ensure successful PBL outcomes.

4.1.7. PBL Develops Desired Skills

PBL develops desired skills theme reflected PSTs’ focus on the nurturing of the students’ creativity, critical thinking, problem solving, and collaborative skills. We observed a wide variation in the depth of PST reflection and elaboration on specific processes through which students participating in PBL might develop those skills. While some PSTs, as shown in Maria’s statement, simply stated that “[PBL] helps students to practice 21st century skills which will be crucial in their lives,” others, as exemplified in Kelly’s statement, went a step further and listed specific skills, as follows: “Throughout the process, students will learn to work with others, solve problems, and communicate effectively which are skills needed to succeed in today’s society.” However, a number of PSTs connected skill development to the effective pedagogical action that leads to consequential student engagement. For example, Annette asserted the following: “Lastly, the lesson plan should allow for trial-and-error time, so students can really think through the process and make productive adjustments leading to deeper learning and increased critical thinking.” Thus, PSTs articulated different levels of understanding of the coveted 21st century skills and their integration into PBL.

4.1.8. PBL Differs from Traditional School Instruction

The theme of PBL differs from traditional school instruction emerged from PSTs comparing and contrasting didactic teaching methods with PBL. PSTs often highlighted the passive nature of traditional schooling. Kelly wrote the following: “In a traditional classroom, students are asked to sit at their desk/table and complete worksheets on a subject, or to sit and copy notes down.” PSTs often contrasted didactic teaching with their experiences as students in our class to emphasize the effectiveness of PBL. Ella reflected on her learning, as follows: “We could have sat in the classroom and read about composting all day but I would definitely not have retained as much information as I did through our project.” Through their reflections on the contrast between traditional instruction and PBL, these PSTs were able to articulate changes in their beliefs about the need for direct instruction. Ella continued in her reflection, as follows: “This assured me that I did not need to take the ‘typical’ route of workbooks and note-taking to help my students pass their final exams.”

Similarly to the PSTs’ reflection on the role of the teacher in PBL, the contrasting of PBL with traditional, didactic instruction illuminated how PSTs used their experiences in the science methods class to begin navigating from their state as learners to their state as teachers. Having experienced effective PBL as science learners, PSTs contrasted this form of learning with traditional instructional methods, which they perceived to be less effective. In turn, PSTs become aware of their own sense of agency and autonomy for making transformative pedagogical choices in their future classroom, shaping the learning experiences of their students.

4.1.9. PSTs’ Emotions Toward PBL Instruction

We used the PSTs’ emotions towards PBL instruction theme to capture a wide range of emotions that were expressed by PSTs in their reflections on PBL. PSTs expressed feelings ranging from enjoyment, indifference, and lack of interest to feeling stressed and lost. The affective dimension of PST blogs functioned to help PSTs define their own feelings towards PBL, as well as to enable them to empathize with their future students and other educators implementing PBL. Leona was able to trace her feelings of being stressed as a participant in PBL to her need for clear direction, as follows: “As someone who likes feedback and direction, I found our project-based learning on composting to be very stressful.” PSTs seemed to be utilizing their feelings as learners in a PBL class as a way to understand how their future students might feel about PBL. For example, Carrie reflected positively on her experience, as follows: “I thoroughly enjoy engaging in project-based learning as an adult and know that students also enjoy it.” Reflecting on the need for teachers to make “on-the-fly” adjustments to PBL and to ensure students are thinking deeply about projects, Beth wrote the following: “Both of these things can be very difficult and stressful to some people—depending on the day, it can be difficult and stressful to me!”

PSTs’ feelings of stress seemed to have originated from two primary sources—the uncertainty experienced as a learner immersed in scientific inquiry and the uncertainty of a new teacher doubting her own ability to ensure students’ science learning through PBL. The inherent uncertainty present during scientific inquiry left some teachers feeling stressed, whereas others enjoyed the challenge of investigations. The stress that PSTs described related to doubts in their ability to effectively manage a PBL classroom provided an insight into the feelings that underpin the practice of new teachers.

4.2. Connecting the Dominant Themes to the Components of PCK

Because the development of integrated and coherent PCK is critical for teachers’ effectiveness (Magnusson et al., 1999), we investigated if and how the dominant themes from the PSTs’ blogs connect to the components of PCK. Although each of the components implies a different kind of transformation of knowledge about pedagogy, subject matter, and context, they function as a whole (Magnusson et al., 1999). Thus, our goal was to illuminate those components that might need additional support, as well as those that are sufficiently addressed in this PBL-based science methods course.

The first component of the Magnusson model, orientations toward teaching science, is of critical importance for a teacher’s conceptualization of science instruction at a particular grade level, as well as the planning, development, and enactment of science lessons (Magnusson et al., 1999). Magnusson and colleagues emphasized that the key distinguishing factor for a teacher’s orientation towards science teaching is not the specific method a teacher uses, but the purpose of utilizing it. PSTs’ emerging knowledge and beliefs about the goals and characteristics of science instruction were evident in the following eight themes: learner agency in PBL, PBL as an authentic learning experience, PBL as a hands-on activity, the affordances/limitations of PBL as an instructional approach, a teacher’s role in PBL, PBL develops desired skills, PBL differs from traditional school instruction, and PSTs’ emotions towards PBL instruction (

Table 5. Dimensions of PCK for science teaching and connecting themes.

Dimension of PCK for Science Teaching	Connecting Themes	No. of Connected Themes
Orientations towards science teaching	Learner agency in PBL PBL as an authentic learning experience PBL as a hands-on activity PBL as an instructional approach A teacher’s role in PBL PBL develops desired skills PBL differs from traditional school instruction PSTs’ emotions towards PBL	8
Knowledge of science curricula	A teacher’s role in PBL Cost of PBL implementation PBL as an instructional approach	3
Knowledge of students’ understanding of science	PBL as an authentic learning experience PBL as an instructional approach A teacher’s role in PBL	3
Knowledge of instructional strategies	PBL as an instructional approach PBL as an authentic learning experience PBL as a hands-on activity A teacher’s role in PBL PSTs’ emotions towards PBL PBL differs from traditional school instruction	6
Knowledge of assessment of scientific literacy		0

).

Magnusson et al. (1999) conceptualized the second component of their model, knowledge of the science curriculum, which comprised two categories—knowledge of specific goals and objectives dictated by national, state, and district documents and authorities, and knowledge of specific curricular programs. The themes that particularly connected to this component of PCK are the cost of PBL instruction, PBL as an instructional approach, and a teacher’s role in PBL. The PSTs in this study demonstrated their knowledge of multiple aspects of PBL including the unique role of teachers as a co-learner and a guide in PBL. Through their discussions of the cost of PBL, PSTs also expressed their awareness of the sometimes competing and conflicting objectives emphasized in the reform documents and in practice, in the context of local schools, by the various stakeholders that they are likely to encounter as they attempt to implement PBL.

The third component of the Magnusson model, knowledge of students’ understanding of science, focuses on the knowledge that teachers need to have about their students in order to enable them to achieve the desired learning goals. This component includes knowledge of prerequisites for learning specific science concepts and knowledge of the science topics and areas where students are likely to experience difficulties. The themes of PBL as an authentic learning experience, PBL as an instructional approach, and a teacher’s role in PBL illuminated our participants’ emerging knowledge and awareness of their students’ knowledge, skills, and feelings, which might support or thwart students’ science learning. The PSTs drew on their own experiences as learners in our class and as new teachers during their field teaching experiences, as they reflected on areas where their students might need additional support.

Knowledge of the instructional strategies component of PCK for science teaching comprises knowledge of subject-specific and topic-specific strategies (Magnusson et al., 1999). Magnusson et al. (1999) pointed out that teachers’ strategy use is driven by their beliefs about particular instructional approaches. Through their reflections, PSTs were able to describe the key aspects and features of PBL, as well as a teacher’s role in PBL in science. It is not surprising that their discussion of the topic-specific strategies, which encompassed representations and activities, centered on issues of sustainability and composting, which are central to the Bio-Sphere curriculum. Hence, the themes that connect to this component of PCK are PBL as instructional approach, a teacher’s role in PBL, PBL as an authentic learning experience, PBL is hands-on, PBL differs from traditional school instruction, and PSTs’ emotions towards PBL instruction.

We found that none of the prevalent themes connected to the knowledge of the assessment of scientific literacy component of PCK. Magnusson et al. (1999) asserted that this component consists of the knowledge of which aspects of students’ science knowledge are important to assess and the knowledge of the methods that might be utilized for this purpose. Our participants’ blogs included only minimal and passing references to the assessment and evaluation. Lilly’s post, in which she mentioned the need to conduct on-the-fly assessments, is representative of this superficial attention to assessments in PST blogs, stating the following: “We also have to evaluate on the fly if the direction a student is going will be one that allows that student to reach the learning goals.” However, she provided no further details about what aspect of students’ knowledge she might evaluate or how. Additionally, although the PSTs reflected on the use of science notebooks and the creation of original products in PBL, connections to the potential use of the student-created artifacts for a formative or summative assessment of students’ knowledge were absent.

In summary, the dominant themes and a further examination of our data seem to indicate that PSTs’ emerging PCK, as evidenced in their reflective blogs about PBL, connects to the first four components of PCK as conceptualized by Magnusson et al. (1999), but seems to be missing the component of knowledge of the assessment of scientific literacy (Figure 1).

The radial chart, scaled from zero to eight, shown in Figure 1, illustrates the relative prominence of the orientations towards science teaching dimension as being the most emphasized dimension in PST blogs, connecting to eight themes. Following this, knowledge of instructional strategies showed moderate prominence, connecting to six themes. The dimensions of knowledge of science curricula and knowledge of students’ understanding of science, both of which connect to three themes, were less discussed. Knowledge of assessment of scientific literacy, which did not connect to any of the blog themes, is represented by the dot at the chart’s center. This distribution suggests that while PSTs actively reflected on their instructional approaches, curriculum understanding, and aspects related to students’ understanding of science, they did not explicitly reflect upon aspects related to robust assessment methods.

Our data seem to provide the strongest evidence for the connections to the orientations towards science teaching and the knowledge of the instructional strategies components of PCK, followed by the knowledge of science curricula and the knowledge of students’ understanding of science, while there were no observed connections to the knowledge of assessment of scientific literacy. Thus, there is evident asymmetry and imbalance among the emerging components of PCK.

5. Discussion and Implications

The purpose of our study was to examine elementary PST reflections on PBL after participation in a semester-long PBL-based science methods course and to identify the main themes (RQ1) and illuminate the connections between the themes and the PSTs’ emerging PCK (RQ2). Using content analysis, we identified the following nine main themes: (a) learner agency in PBL, (b) cost of PBL implementation, (c) PBL as an authentic learning experience, (d) PBL as a hands-on activity, (e) affordances/limitations of PBL as an instructional approach, (f) a teacher’s role in PBL, (g) PBL develops desired skills, and (h) PBL differs from traditional school instruction. We found that the greatest number of common themes from the blogs of three cohorts of PSTs connected to the orientations towards science teaching and the knowledge of the instructional strategies components of PCK, followed by the knowledge of science curricula and the knowledge of students’ understanding of science. None of the prevalent themes connected to the knowledge of assessment of scientific literacy component of PCK. Thus, we found that the development of teachers’ PCK is asymmetric and asynchronous, meaning that different components of PCK develop to different levels at different points in a teacher’s career.

As we expected, based on earlier studies about the effectiveness of the reflective practices (Cite et al., 2017; Kewalramani et al., 2025; Parker & Heywood, 2013; Wongsopawiro et al., 2017), PSTs’ engagement in reflection and the writing of the blogs were effective for making their personal PCK explicit, illuminating progress toward well-developed PCK that characterizes effective, experienced teachers. Hall (2018) emphasized that reflection opportunities needed to provide the supporting structure for critical reflection on pedagogical practice. Although we provided a structured sequence of blog prompts throughout the semester that were well-aligned to the coursework, PSTs’ blogs at the end of the semester showed varied understanding and levels of reflection on the key pedagogical aspects of PBL.

Overall, our findings about asymmetric and idiosyncratic PCK development align with those of previous studies (e.g., Connolly et al., 2023; Oztay et al., 2023; van Driel & Berry, 2010; Wongsopawiro et al., 2017), while offering important insights about which aspects of PBL were salient and which were not present in PSTs’ end-of-the-course reflections. Almost all PSTs wrote about learner agency in PBL—theme a—and understood its importance. Similarly, the costs of PBL implementation—theme b—were well understood, and PSTs even commented on the potential negative impact of PBL implementation on the relationships with school administrators and parents who might not support it. Hence, the PSTs demonstrated a basic understanding of innovative pedagogical practices being “acts of rebellion” when implemented in more traditional school environments (Hanuscin & Hian, 2009). In contrast, PST reflections on PBL as an authentic learning experience (theme c) did not show understanding of project authenticity as an age-appropriate approximation of scientific practice for their students. Instead, they focused on the superficial aspects of PBL and emphasized PBL as a hands-on activity (theme d). Taken together, these reflections show that PSTs initially had naïve knowledge of instructional strategies. However, when reflecting on PBL as an instructional approach (theme e), PSTs began to grapple with some more nuanced aspects of science teaching. They started to think about the transferability of their learnings into their own pedagogical practice, which is challenging for new teachers (Connolly et al., 2023). They recognized the uncertainty that is inherently present in science practices and the need to think through the ways to support their students in managing it while allowing time and space for students’ exploration. This is an important finding as the research shows that the PSTs’ disciplinary perspectives and knowledge shape their practice (H.-H. Wang et al., 2025). Moreover, combined with the PSTs’ reflections about the teacher’s role in PBL (theme f), our findings indicate that PSTs started to think about the need to balance classroom control with student agency, which is key for classroom engagement in authentic science inquiry (Dragnić-Cindrić et al., 2024; Magnusson et al., 1999).

We observed a wide variation in PSTs’ understanding of how PBL develops desired skills for students (theme g), confirming that PCK development is idiosyncratic even in the same settings (Oztay et al., 2023). PSTs recognized that PBL differs from traditional school instruction (theme h) and expressed a wide range of emotions about it (theme i). While some PSTs expressed the uncertainty they felt in the science classroom, both as a learner and as a new teacher, left them feeling stressed, others felt energized by it. These findings are important because they provide an insight into the feelings that underpin the practices of new science teachers. They are also indicative of the individual differences in the ways that people deal with uncertainty (Kruglanski & Webster, 1996; Sorrentino & Roney, 2000)—an area that needs further investigation. It is possible that PSTs who are stressed by the uncertainty that is an integral part of authentic scientific inquiry and modern science classrooms might be more prone to reverting back to teacher-centered instruction, thus eliminating uncertainty rather than using it as a resource for science learning. Such PSTs might need additional support to understand scientific uncertainty, as well as the uncertainty related to effective classroom management and the ability to regulate through it.

The reflections of PSTs in our science methods course seem to be missing connections to the knowledge of assessment of scientific literacy components. This finding carries important implications for science teacher educators who are implementing PBL in their own classrooms. Consistent with findings from research with in-service teachers (van Driel et al., 2014), this finding may indicate that PSTs were not able to connect the traditional and omni-present institutional requirement for assessments of student knowledge with PBL, which they perceived as a “non-traditional” method. The holistic development of pre- and in-service teachers’ PCK for science teaching necessitates that knowledge of the assessment of scientific literacy components is specifically and thoughtfully addressed in teacher preparation and professional development courses. One way to do this is to explicitly discuss and model good assessment practices including what dimensions of students’ science learning need to be assessed at different grade levels, in addition to why and how. Additionally, it is possible that PSTs’ blog reflections contained no deep and specific reflections on the assessments of students’ knowledge because they assumed that such knowledge develops and exists as an integral part of broader pedagogical practice. Thus, to foster PST PCK development, it would likely be beneficial to include explicit instruction on models of PCK in PST preparation courses. We posit that raising PSTs’ awareness of PCK dimensions and their interconnected nature will empower PSTs to have greater control over their own learning, not only during their initial training in teacher preparation programs but also in future professional development and career growth.

5.1. Limitations of the Study

In addition to reflection on practice, the other main drivers of teachers’ PCK development are teaching experience, engagement in practical applications of PBL, and subject matter knowledge (Atay et al., 2010; Erviana et al., 2022; Li & Copur-Gencturk, 2024; Wongsopawiro et al., 2017). Pre-service teachers in this study had no prior teaching experience. We focused on teachers’ private PCK and did not follow future teachers into their classrooms to observe their PCK and skills in action (Gess-Newsome, 2015). Although we are aware that this is one of the limitations of our study, we believe that this study contributes to the nuanced knowledge about PSTs’ emerging PCK at the time when they are ready to leave their teacher preparation program.

Another limitation is that we did not test PSTs’ science knowledge before or after their participation in the science methods course. Studies show that subject matter knowledge can facilitate faster PCK development (Li & Copur-Gencturk, 2024), so it would be important for future studies to include measures of PSTs’ subject matter knowledge.

5.2. Future Directions and Implications for Teacher Education

Our findings have some important implications for teacher educators. The assessment design should attend to both knowledge about the dimensions of scientific literacy that need to be assessed, as well as the effective methods for assessing specific aspects of students’ science learning (Magnusson et al., 1999). In the next iteration of the NameDeidentified curriculum, we plan to afford PSTs with ample opportunities to experience, implement, and design a variety of assessments. We suggest that in their role as students, PSTs should experience both instructor- and self-administered assessments of individual and group work at the end of PBL tasks. We hypothesize that employing self-assessments might foster PSTs’ reflection on their own learning, as well as on the effectiveness of the particular method of assessment. In their role as new teachers, PSTs should be provided with opportunities to assess actual and hypothetical student-created PBL artifacts. Teacher educators might use video clips of PBL at different grade levels to facilitate PSTs’ practice of on-the-fly assessments and reduce the stress related to the uncertainty experienced in science teaching and learning.