Views of Chinese middle school chemistry teachers on critical thinking

Abstract

Critical thinking, a rational and open higher-order thinking mode in human cognition, is becoming imperative to success in modern life. Therefore, cultivating students’ critical thinking has become a common goal of education reform worldwide. Teachers play a crucial role in cultivating students’ critical thinking. However, existing studies have paid little attention to teachers, especially middle school teachers’ knowledge and understanding of critical thinking. Therefore, this study aimed to explore the perspectives of ten Chinese middle school chemistry teachers on critical thinking using concept maps, thinking aloud, and in-depth interviews based on concept maps. Results showed that most of the teachers believed that critical thinking means reflection and questioning and requires evidence awareness. All teachers had a positive attitude towards critical thinking and believed that it can promote evidence awareness, problem solving, decision making, teaching evaluation, logic, and systematisation. Teachers recognised that critical thinking can be taught, and the major factors affecting the development of students’ critical thinking were the environment, students themselves, teachers, evaluation, subject characteristics, and types of knowledge. Several strategies for developing students’ critical thinking in chemistry teaching were proposed, including setting diversified and different types of chemistry courses, developing controversial curriculum themes in real situations, and implementing experimental, project-based, problem solving, and history-based teaching. In addition, this study showed that teachers and students promoted the development of critical thinking within one another. Further, this study demonstrated an effective methodology for probing individual subjective thoughts.

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Introduction

With the continuous improvement of social informatisation, accelerating social change, and the strengthening of social complexity and interdependence, the ability of critical thinking is becoming imperative to success in modern life (Miri et al., 2007). Whether in life or in professional fields, we often fall into the dilemma of not knowing what to believe or do. Compared with those who lack reflection or always react instinctively, people proficient in critical thinking can screen, absorb, segregate, and store information efficiently so that they can control their lives better and make wise decisions. Therefore, critical thinking is among the necessary transferable skills for successful navigation through our increasingly dynamic and complex world (Halpern, 1998). Furthermore, it can resist the illusion, deception, superstition, and misunderstanding of ourselves and our surroundings (Sumner, 1940).

Critical thinking enables wise decisions in one's personal, professional, and civic life (Marshall and Tucker, 1992). Concurrently, critical thinking, as a rational and open higher-order thinking mode in human cognition, is an important part of students’ intelligence and creativity. Critical thinking skills are essential for the promotion of metacognitive understanding (Schraw et al., 2006). Therefore, cultivating students’ critical thinking has become the common goal of education reform globally. Critical thinking is a basic learning and academic skill such as reading and writing in the international education community. It is a source of the power of questioning, exploration, and a requisite to create knowledge and rationality. According to the literacy framework of organisations and regions such as the EU, the OECD, the US, and Australia, critical thinking has always been regarded as one of the core competencies for individuals facing the 21st century. In China, the central government has initiated the latest round of curriculum reform and issued The General Senior Secondary School Chemistry Curriculum Standards in 2018 (MoE, 2018) and The Compulsory Education Chemistry Curriculum Standards in 2022 (MoE, 2022), both of which highlighted the core competencies in chemistry and emphasised ‘critical thinking’, ‘critical spirit’, ‘rational thinking’ and ‘critical questioning’ (Wei, 2020).

In school education, teachers guide students’ learning, and their ideas and behaviours always influence the development of students. The premise of developing students’ critical thinking is that teachers need to have a critical spirit and understand the connotation, characteristics, importance, and general development path of critical thinking. It is difficult to imagine how a teacher without critical thinking would develop students’ critical thinking. Studies have shown that teachers’ beliefs about critical thinking activities of different groups of learners may affect students’ academic performance (Warburton and Torff, 2005). Therefore, this study mainly discussed the following questions: (1) how do middle school chemistry teachers understand the concept of ‘critical thinking’? (2) what are the main factors that affect the development of critical thinking of teachers and students? and (3) how do middle school chemistry teachers develop students’ critical thinking in their chemistry classroom teaching? Reasonable suggestions and strategies for critical thinking teaching to chemistry teachers were put forward by exploring the above three questions.

Theoretical background

Emergence and development of the concept of ‘critical thinking’

The origins of critical thinking can be traced back to Ancient Greece when the ‘art of midwifery’ posited by the famous philosopher Socrates was the teaching practice of critical thinking and emphasised seeking the truth. The famous American philosopher and educator John Dewey posited critical thinking as a skilled concept for the first time in 1910. He pointed out in his book how we think that ‘Active, persistent, and careful consideration of any belief or supposed form of knowledge in the light of the grounds that support it, and the further conclusions to which it tends, constitutes reflective thought’ (Dewey, 1910). This ‘reflective thought’ proposed by Dewey is essentially a systematic test of assumptions. Inspired by John Dewey, the American Progressive Education Association devoted itself to propelling the development of ‘critical thinking’ in the following 40 years. In 1925, Goodwin Watson and Edward Glaser pioneered the development of the Watson–Glaser Critical Thinking Appraisal (WGCTA). Glaser further proposed that critical thinking included the attitude of being willing to think carefully about the problems and objects people encounter, the knowledge of logical exploration and reasoning methods, and the skills of using these methods, including the ability to solve problems systematically (Glaser, 1941).

From the 1940s to the 1960s, several researchers changed the expression ‘belief or assumed knowledge’ which is the starting point for reflective thought and critical thinking to ‘statement’, and incorporated the ‘examination of statement’ into the definition of critical thinking (Smith, 1953; Ennis, 1962). However, although researchers used the word ‘statement’ to express the understanding of critical thinking at this stage, they limited critical thinking more to the scope of ‘evaluation’ and paid less attention to problem solving and scientific methods, which somewhat narrowed the interpretation of critical thinking.

In the 1970s and 1980s, an increasing number of researchers began to pay attention to the teaching of critical thinking, and many new understandings of the definition of critical thinking emerged accordingly. For example, Ennis believed that critical thinking ‘is reflective and reasonable thinking that is focused on deciding what to believe or do’ (Ennis, 1985); Lipman pointed out that critical thinking ‘relies upon criteria, is self-correcting, and is sensitive to context’ (Lipman, 1988); Siegel defined critical thinking as ‘thinking appropriately moved by reasons’ (Siegel, 1988); and Paul pointed out that critical thinking ‘is disciplined, self-directed thinking which exemplifies the perfections of thinking appropriate to a particular mode or domain of thinking’ (Paul, 1989). The above definitions of critical thinking broaden the understanding of critical thinking so that it is no longer limited to the scope of ‘evaluation’ but also includes many aspects of solving problems. In addition, during this period, researchers highly emphasised the attitude and dispositions of critical thinkers besides critical thinking skills.

In the 1990s, researchers expanded the definition of critical thinking and highlighted critical thinking contents, metacognitive skills, and thinking dispositions. A Delphi Report on critical thinking was submitted to the American Philosophical Association in 1990. This Delphi research lasted two years, beginning in 1988 and ending in 1989, and involved 46 experts from the fields of philosophy, education, social science, and physical science who had experience and expertise in critical thinking instruction. Their consensus on critical thinking was ‘purposeful, self-regulatory judgment which results in interpretation, analysis, evaluation, and inference, as well as explanation of the evidential, conceptual, methodological, criteriological, or contextual considerations upon which that judgment is based’ (Facione, 1990a). Concurrently, the report listed several mental habits that an ideal critical thinker should have: inquisitiveness, well-informedness, trustfulness in reason, open-mindedness, and flexibility. Moreover, the experts found good critical thinking to include both skill and dispositional dimensions. The experts recognised six cognitive skills, including interpretation, analysis, evaluation, inference, explanation, and self-regulation, as the central or core critical thinking skills (Facione, 1990a).

Since the beginning of the 21st century, several researchers have studied the definition and evaluation of critical thinking, making its definition more refined, multidisciplinary, and diverse. For example, critical thinking was recognised as a set of cognitive skills, strategies or behaviours (Tiruneh et al., 2014), and the concept of critical thinking was suggested to focus on adherence to standards explicitly (Bailin, 2002). Seven definitional strands of critical thinking were identified by investigating the ideas of experts from history, philosophy, and culture disciplines—judgement, scepticism, simple originality, sensitive readings, rationality, an activist engagement with knowledge and self-reflexivity (Moore, 2013). A study that examined the perceptions around critical thinking of Australian chemistry students, chemistry teaching staff and employers of chemistry graduates found that respondents identified themes such as ‘analysis’, ‘critique’, ‘objectivity’, ‘problem solving’, ‘evaluate’ and ‘identification of opportunities and problems’ when asked to define critical thinking (Danczak et al., 2017). Similarly, student perceptions of ‘critical thinking’ in the context of organic chemistry courses were explored (Ryan, 2022).

From the development of the concept of critical thinking for nearly a century, a clear and well-accepted understanding of the definition of critical thinking has not been developed so far. Some researchers simply emphasised critical thinking to evaluate pre-existing intellectual outcomes such as hypotheses, statements, and arguments, while others argued that critical thinking could also create intellectual outcomes such as explaining complex phenomena, making decisions in complex situations, and answering difficult questions. Some definitions of critical thinking focused on skills, some on attitudes, and others emphasised both. However, some commonalities exist between the numerous definitions. Critical thinking, as a kind of thinking, can be applied to all topics, and it includes carefully deliberated evidence, reflection, review, and delayed judgement. The aim of critical thinking is to make explicit judgements. Furthermore, a critical thinking player needs to have relevant knowledge, skills, attitudes, and behavioural tendencies, among others.

Critical thinking teaching

Although there are some differences in the definitions and perceptions of critical thinking, the significance of critical thinking for individual development and the cultivation of students’ critical thinking has become a consensus among researchers. Critical thinking skills do not improve simply with age (Facione, 1990b), but critical thinking can be acquired (Facione et al., 2009), and proper critical thinking teaching improves students’ critical thinking skills.

Critical thinking teaching is not a simple skill training but the teaching that gives students the ability to acquire, apply, reflect, and improve their critical thinking with purpose and high standard, including knowledge, concepts, methods, principles, and skills of critical thinking (Facione, 1990a; Bailin et al., 1999). Concurrently, studies have shown that teaching critical thinking, much like teaching something else, requires both skills and mental habits. It would be more effective when involving students in analysing reflexively those rich and real problems that closely reflect the real challenges and problems in life (Tiwari et al., 2006). In the process of critical thinking teaching, students can participate in deductive judgement through direct guidance, teacher imitation, judgement, and feedback which help them accumulate the required intellectual resources. Meanwhile, a teaching environment that values and stimulates critical thinking should be provided in critical thinking teaching (Bailin et al., 1999). The practical environment and inquiry learning topics are considered to be beneficial for developing students’ critical thinking (Danczak, et al., 2017). In addition, critical thinking teaching is often closely linked to metacognitive habits’ development because they can reinforce each other (Kuhn, 1999). The main challenge is whether critical thinking skills learned by learners in one context can be successfully migrated to other contexts. Therefore, critical thinking teaching should emphasise the cultivation of students’ meta-thinking and abilities to transfer to different situations (Halpern, 1998).

There are generally four specific approaches to teaching critical thinking, namely the general approach (to develop a dedicated critical thinking course), the infusion approach (to popularise the teaching objectives of critical thinking in discipline courses), the immersion approach (to conceal the objectives of critical thinking teaching in discipline courses) and the mixed approach (to make the development of critical thinking skills clear and parallel to subject teaching) (Ennis, 1989). In addition, Ennis argued that critical thinking is domain-specific (Ennis, 1990), and critical thinking teaching should be integrated with specific disciplines or content (Pithers and Soden, 2000). In recent years, with the development of critical thinking teaching, many teaching strategies and methods for developing critical thinking have emerged: for example, Socratic Questioning instruction (Elder and Paul, 1998), problem-based learning (Norman and Schmidt, 2000), critical debates (Freeley and Steinberg, 2008), science writing heuristics (Hand et al., 2018), and game-based learning (Mao et al., 2022).

Specific to the discipline of chemistry, researchers also made numerous attempts to promote critical thinking in chemistry teaching, many of which occurred in chemical experiment inquiry teaching. For example, scientific writing heuristics (Stephenson and Sadler-McKnight, 2016), evidence- and reasoning-based teaching (Wang et al., 2021), guided-inquiry-based introduction focused on writing and reflection (Gupta et al., 2015), problem-based laboratory teaching (Quattrucci, 2018), designing the pre-experiment activities that guide students to engage in critical thinking (van Brederode et al., 2020), reframing prelab and post-lab questions (Rodriguez and Towns, 2018), authentic scientific laboratory practice (Chase et al., 2017), and other ways are used to develop and promote students’ critical thinking ability. Other researchers focused on improving and enhancing students’ critical thinking through chemical instrumentation games (Henderson, 2010), community-based inquiry (Goeden et al., 2015) and Internet-assisted chemistry classrooms (Tsai, 2001). In addition, courses designed to promote students’ critical thinking have emerged in chemical education research, such as nanotechnology courses specifically designed for non-science majors (Park, 2019) and bookend courses for third-and fourth-year chemistry majors (Klein and Carney, 2014). The above studies on the cultivation of students’ critical thinking focus on how courses and teaching methods promote the development of critical thinking of college students in the undergraduate stage; in contrast, less attention has been paid to junior and senior students, and fewer studies have been conducted on the roles played by secondary chemistry teachers in the process of teaching critical thinking.

The development of teachers’ critical thinking can make them maintain their enthusiasm for educational and scientific research to explore the unique teaching style, which is helpful for teachers to promote the development of students’ critical thinking ability. However, existing studies have paid little attention to teachers, especially middle school teachers’ knowledge and understanding of critical thinking. Therefore, this study took middle school chemistry teachers as research subjects, aiming to explore middle school chemistry teachers’ knowledge and understanding of the concept of ‘critical thinking’, as well as the practice status and teaching strategies of middle school chemistry teachers in developing students’ critical thinking in classroom teaching. Therefore, we analysed the core factors that affect the development of critical thinking of teachers and students. Furthermore, we put forward rationalised suggestions for enriching middle school chemistry teachers’ knowledge of critical thinking and applying critical thinking to teaching to promote teachers’ professional development.

Methods

Development of research tools

The research methods used in this study mainly included using concept maps, thinking aloud, and in-depth interviews based on concept maps.

Thinking can be taught and evaluated (Cai, 2021). To conduct qualitative research on this abstract concept of thinking, researchers are committed to developing a general method to evaluate thinking and its related knowledge. Concept maps have been proved to be an effective tool for investigating individuals’ knowledge, views and attitudes towards thinking (Semmler and Pietzner, 2017; Semmler and Pietzner, 2018). A concept map is a structured two-dimensional representation of knowledge resources, information or ideas about a topic. It is a way of representation that embodies propositions and concepts. The concept map's representation structure corresponds to the knowledge structure in the brain (Yin et al., 2005), so the cognitive knowledge structure can be visualised with a concept map (Novak and Cañas, 2008), which can be used to reflect the individual's cognition of a topic.

The concept map mainly includes nodes, connections, and connectives. Concepts, propositions, hierarchical structures, and cross-connections are the four core elements of a concept map. A node is usually a concept placed in a box. A concept is defined as an observable regularity or pattern in an event or a thing or a record of an event or a thing, and it is specified by a symbol, usually a word. Concepts can be regarded as the basic building blocks of knowledge. Two or more concepts can be connected by appropriate ‘connectives’ to form a ‘proposition’, which is the real meaning unit. Sometimes there are some relationships or propositions between distant concepts on the concept map, which represent the ‘cross connections’ on the concept map, and cross-connections can often lead to new creative ideas. The concept map is generally arranged in a hierarchical structure, from top to bottom, the concept is becoming more and more specific, and the inclusiveness of the concept is gradually becoming smaller. There are five basic structural classifications formed by the interconnection between the constituent elements: linear, circular, hub or spoke, tree, and network or net (Yin et al., 2005). These structures reflect the interrelationship of terms in the minds of participants, and different network structures represent the depth, universality, and flexibility of the understanding of concepts or topics. Among them, the network or net structure is considered to be the most complex, while the linear structure is considered to be the simplest.

The concept map tool we developed mainly included two parts. The first part is the standard concept map taking ‘oxidant’ as an example and a brief description of the concept map. Because participants have different knowledge and experience in creating a concept map, this part intends to let participants have a rapid cognition and understanding of the concept map and their drawing according to the examples. The second part is to ask participants to build a concept map of ‘understanding critical thinking’. The form of this part we initially determined is an open concept map, which only provides participants with the research purpose and core concept theme ‘critical thinking’, and participants sort out and draw based on their existing knowledge, experience and understanding without guidance. Then, we selected a junior high school chemistry teacher and a senior high school chemistry teacher for the test and found that it was difficult for them to quickly create a concept map around ‘critical thinking’, and these test participants said that it was very difficult to draw a concept map in a short time, and they did not know how to start. In this case, we decided to adopt a restrictive concept map. This concept map does not give a fixed structure but provides some nodes and connectives needed to build the concept map. Based on the provided concepts and connectives, it will be relatively easy for participants to build the concept map, and the given qualifiers will also stimulate participants’ thinking, thus generating more concepts and propositions. At the same time, this concept map can be easily compared and evaluated, which can quickly determine the similarities and differences in participants’ understanding. It is also more conducive to comparing with the data in the literature. Based on the existing literature research on critical thinking and the concepts given by the participants in the test, we drew and generated a concept map of critical thinking as shown in Fig. 1 after the demonstration of two university chemistry teaching theory professors, to obtain a structured overview of the concepts of critical thinking in the literature and also provide a basis for the participants to provide reference nodes and reference connectives. In Fig. 1, a total of 24 reference nodes and 25 reference connectives are extracted.

Fig. 1 Critical thinking concept map drawn by researchers.

Based on the above work, we finally developed a ‘concept map tool for middle school chemistry teachers’ understanding of critical thinking’ (refer to Appendix 1). The first part provides a brief description of the concept map according to the standard concept map of ‘oxidant’. The second part contains relevant information, reference nodes, and connectives for constructing the critical thinking concept map. This part is presented independently to avoid irrelevant interference with the participants’ thinking.

Furthermore, to fully understand the basis and real ideas of the participants in drawing the concept map, and to explore the participants’ interpretation and in-depth understanding of some propositions in the concept map, we also adopted the method of ‘think aloud’ and in-depth interviews based on the concept map. The method of thinking aloud can not only understand a person's thoughts but also reveal a person's cognitive process (Van Someren et al., 1994). As for the oral expression of ideas, participants can express their ideas at any time during the concept map drawing process, that is, ‘oral expression at the same time’, or express their ideas immediately after creating the concept map, that is, ‘retrospective oral expression’ (Ericsson and Simon, 1980).

Concept map-based in-depth interviews are conducted after participants draw concept maps and think aloud. Based on the drawn concept maps, the participants were interviewed in-depth combined with the practical cases of teaching critical thinking from the aspects of understanding of critical thinking, the influencing factors and ways of teachers’ critical thinking development, and the influencing factors and promotion strategies of students’ critical thinking development, to explore teachers’ understanding of critical thinking further.

Participants

In this study, five front-line junior middle school chemistry teachers (numbered from junior A to junior E) and five front-line senior high school chemistry teachers (numbered from high A to high E) were randomly selected for formal research. These teachers came from different schools in Qingdao, Shandong Province, China, with different genders, teaching ages, educational backgrounds, etc. The specific information is shown in Table 1. The differences in the research subjects laid the foundation for this investigation and supported the reliability of the investigation results.

Table 1 Participant information

Number	Academic period	Gender	Teaching age (years)	Qualifications
Junior A	Junior high school	Female	>20	Undergraduate
Junior B	Junior high school	Female	1–5	Postgraduate
Junior C	Junior high school	Male	>20	Undergraduate
Junior D	Junior high school	Male	10–20	Postgraduate
Junior E	Junior high school	Female	1–5	Postgraduate
High A	High school	Female	1–5	Postgraduate
High B	High school	Female	>20	Undergraduate
High C	High school	Female	>20	Undergraduate
High D	High school	Male	10–20	Postgraduate
High E	High school	Male	10–20	Undergraduate

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Implementation of the study

The implementation of this study lasted for one month. At the beginning of the study, the participants were informed about the purpose, content, and process of the study. Then, they signed a consent form to clearly communicate their acknowledgment of the study and consent to being fully videotaped and audio-recorded. The ten teachers participated in the study voluntarily by face-to-face investigation, and they could leave the study at any time. Pseudonyms were used for the participants to keep their identities confidential.

After one of the researchers explained the purpose and implementation process of the research in detail, the participants received the first part of the critical thinking concept map tool on site. After ensuring the full understanding of the illustrated concept map, the researcher presented them with the second part of the concept map tool, that is, draw a critical thinking concept map without the prompt of the researcher. Simultaneously, participants are required to express their thinking activities loudly in their language during or after the production of concept maps, and carry out the think-aloud of ‘simultaneous oral expression’ or ‘retrospective oral expression’. Finally, the participants were interviewed in-depth based on the concept map. During the research process, researchers can affirm the participants’ ideas or statements at an appropriate time so that the participants can continue to participate in the investigation but avoid interfering with the cognitive process of the participants (Fonteyn et al., 1993) and do not comment on the participants’ ideas and statements.

After each survey, to make the concept map drawn by the participants more precise and easier to analyse, IHMC CmapTools was used to redraw the concept maps constructed by the participants without changing the content and structure. At the same time, the voice thinking and interview results were transcribed in detail. Finally, the researchers got ten complete concept maps and ten records.

Data analysis

We analysed the data from both quantitative and qualitative perspectives. The quantitative analysis mainly analyses the number of reference nodes and new nodes in the concept maps constructed by the teachers from the perspective of statistics to understand the breadth, depth and complexity of teachers’ understanding of critical thinking. The qualitative analysis includes structural analysis and content analysis of the concept maps. That is, researchers analyse the basic structure of each concept map and conduct a multi-angle content analysis of teachers’ answers based on the concept maps, think-aloud, and in-depth interviews.

Specifically, IHMC CmapTools and IHMC CmapAnalysis (Florida Institute for Human & Machine Cognition, 2014) were used for structural analysis and quantitative evaluation of concept maps. At the same time, Constructivist Grounded Theory (CGT) (Charmaz, 2006) was used to analyse the in-depth interview data. CGT provides a way to explore open data while minimising bias and assumptions, and it recognises the role of researchers in the research process. Some researchers have used Charmaz's CGT to explore students’ concepts of critical thinking (Ryan, 2022) and transforming organic chemistry (Flaherty, 2020). All interview data were analysed in MAXQDA 2022 (VERBI GmbH, 2022). According to the analysis process of CGT, we carried out open coding, focused and axial coding, theoretical coding, and other stages of coding. Finally, combined with the concept maps and the interview content, we formed a narrative interpretation framework for middle school chemistry teachers’ understanding of critical thinking and its related content.

Reliability and validity

Reliability and validity are crucial to a study. In qualitative research, the step-by-step verification process of checking, confirming, making sure, and being certain can ensure the reliability and validity and, thus, the rigor of the research. In this study, we followed the verification strategy of credibility and validity of qualitative research established by Morse et al. (2002) and tried our best to do so in the research process: (1) investigators should respond positively, remain open, use sensitivity, creativity, and insight, and be willing to give up any unsupported ideas; (2) for research problems, they should select appropriate research methods to ensure that the methods match the data and analysis procedures; (3) they should sample among the participants who are most representative and know the research topic best; (4) at the same time, they should collect and analyse data; (5) ideas generated from the data are reconfirmed in the newly collected data; and (6) they should develop the theory between the micro perspective of data and the macro concept/theoretical understanding. Based on the development theory of data in the research process, the generated theory is used as a template for comparing and further developing the theory. At the same time, we tried to describe the methodology of this study in detail and quoted as much as possible from concept maps and interviews, to explain the theory better.

Results and discussion

Quantitative analysis

First, we analysed the number of nodes in the concept maps drawn by the ten teachers. After statistical analysis, we found differences in the number of nodes in the concept maps drawn by teachers of different genders, teaching ages, and educational backgrounds, but the differences were not significant. The average number of nodes in the concept maps constructed by the female teachers (17.33) is slightly higher than that of the men (15.23); the average number of nodes used by the high school teachers (17.40) is slightly higher than that of the middle school teachers (15.60); the average number of nodes used by the teachers with 10–20 years of teaching age (18.50) is the highest, followed by that of the teachers with more than 20 years of teaching age (15.60), and finally that of the teachers with 1–10 years of teaching age (14.70); and the average number of nodes used by the teachers with a bachelor's degree (17.80) is slightly higher than that of the teachers with a master's degree (15.20).

We simultaneously counted and sorted the usage times of different nodes in the ten concept maps (Fig. 2). The 24 reference nodes given are selected by teachers, and 19 reference nodes appear in at least five concept maps. This means that teachers participating in the survey can easily connect a given reference node with critical thinking. The most frequently used node is ‘critical thinking’, which is presented in the concept map as the central word by the ten teachers. The least used is ‘rules and boundaries’, which is selected by only one teacher. Most teachers chose ‘teachers’, ‘evidence consciousness’, ‘reflection’, ‘critical questioning’, ‘active classroom atmosphere’, ‘students’, ‘new ideas’, ‘core literacy’ and other nodes. They believe that there is a connection between critical thinking and these concepts. When drawing the concept map, five teachers gave their own opinions based on reference nodes and added new nodes. There are five new nodes, namely ‘learning’, ‘teacher–student interaction’, ‘classroom’, ‘creative thinking’, and ‘self-criticism’.

Fig. 2 Usage times of different nodes in the ten concept diagrams.

Qualitative analysis

(1) Structural analysis. Based on the definition of the basic structure of a concept map by Yin et al. (2005), there are five concept map structures: linear, spoke, circular, net, and tree. The numbers of dominant different structures in the ten concept maps are shown in Table 2. It can be seen from Table 2 that all teachers drew the network and circular structure in the concept map, and most teachers drew linear and spoke structures, which shows that most teachers have a wide and rich understanding of critical thinking. Only four teachers drew a tree structure, which to some extent shows that teachers’ understanding of critical thinking is still a little short.

Table 2 The number of dominant different structures in the ten concept maps

Structure type	Junior A	Junior B	Junior C	Junior D	Junior E	High A	High B	High C	High D	High E	Total
Linear	√		√	√		√	√	√		√	7
Spoke	√	√	√	√		√	√	√	√	√	9
Ring	√	√	√	√	√	√	√	√	√	√	10
Mesh	√	√	√	√	√	√	√	√	√	√	10
Tree	√			√			√	√			4
Total	5	3	4	5	2	4	5	5	3	4

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Among the ten concept maps, the concept maps constructed by four teachers contain five basic structures, and these concept maps have two or more central words, and the connection between nodes is also more complex. In particular, the connection of concepts such as ‘student’, ‘teacher’, ‘curriculum’ and ‘knowledge’ is more complex, which reflects the four teachers’ comprehensive and rich understanding of critical thinking, especially in teaching practice. For example, Fig. 3 is the concept map of critical thinking constructed by the junior A teacher, which includes the spoke structure with ‘teacher’ as the central word, and the tree, net, circular, and linear structure with ‘critical thinking’ as the central word, and a more complex relationship network is formed between nodes around the central word. Further analysis of the basic information of these four teachers can show that three of these four teachers have more than 20 years of teaching experience, and the other is a 10–20-year graduate student, which also shows that, to a certain extent, the experience accumulated in higher education learning and long-term teaching practice can promote the development of teachers’ critical thinking. The junior E teacher is a master's student with 1–5 years of teaching experience. The concept map she constructed contains circular and net structures, with fewer types of structures. Although it can connect the nodes meaningfully, the connection is also relatively simple, which shows that the teacher's understanding of critical thinking is broad but superficial. To further understand the causes of this phenomenon, the subsequent in-depth interview research was focused on it.

Fig. 3 Concept map constructed by the junior A teacher.

(2) Content analysis. Based on the propositional information presented by the teachers in the concept maps and combined with the teachers’ think aloud and in-depth interview materials, we conclude that the teachers’ understanding of critical thinking can be elaborated from seven dimensions: the roles of teachers and students, the personal definition of critical thinking, teachers’ attitude towards critical thinking, the factors that affect the development of students’ critical thinking, the teaching practice of developing students’ critical thinking, and the factors and development ways that affect the development of teachers’ critical thinking.

The roles of teachers and students

According to the ‘teacher’ and ‘student’ nodes and related propositions in the concept map, we can conclude that the roles of teachers and students mainly include three perspectives: the role of teachers, the role of students and the relationship between teachers and students. The role positioning of teachers and students and their relationship positioning can affect the development of critical thinking. In terms of the positioning of the roles of teachers, the proposition ‘teachers need to learn’ put forward by the junior C teacher points out that teachers are first and foremost learners and should become lifelong learners. The concept maps of several teachers include the task proposition that teachers have to teach knowledge, implement curricula, guide students to learn, and cultivate students’ critical thinking. Seven teachers established a direct connection between ‘teachers’ and ‘critical thinking’, among which four teachers mentioned that ‘teachers demand critical thinking’, and three teachers pointed out that ‘teachers teach critical thinking’. In terms of positioning students’ roles, many teachers pointed out that students have the tasks of learning curricula, acquiring knowledge, and developing their core literacy. Five teachers established a direct connection between ‘critical thinking’ and ‘students’ and pointed out that ‘students develop critical thinking’. In terms of the relationship between teachers and students, two teachers established a two-way promotion relationship between teachers and students; that is, teachers can promote the development of students, and the needs of students’ development also promote teachers’ professional growth.

The definition of critical thinking

In the concept maps and interviews, all teachers said that they had not systematically studied the definition of critical thinking but only understood or heard about it. The teachers defined critical thinking based on their own experiences and opinions. In the concept map, six teachers defined it as follows: ‘critical thinking means reflection’, and two teachers mentioned reflection in the interview; six teachers considered that ‘critical thinking means critical questioning’; and two teachers considered that ‘critical thinking includes evidence consciousness’. Other teachers considered that ‘critical thinking means meta-cognition’ (junior B) and ‘critical thinking means analysis’ (high C). The junior D teacher mentioned in the interview that ‘it contains some knowledge and ability, spirit and attitude’. The junior B teacher mentioned that ‘it contains the views and opinions of others and some attitudes and behaviours when making decisions by oneself’. The junior A teacher considered that ‘critical thinking is part of the core literacy’. The junior E teacher considered that critical thinking is ‘a process of reverse exploration of some known things’.

Teachers’ attitude towards critical thinking

Table 3 lists the propositions of critical thinking attitudes in the concept map constructed by the ten teachers. It can be seen that teachers use connectives such as ‘contribute’, ‘promote’, ‘develop’ and ‘need’ to express their positive attitude toward critical thinking. More than three teachers considered that critical thinking promoted evidence consciousness, problem solving, decision making, teaching evaluation, logic and systematicness, and so on. Some teachers considered that critical thinking could produce critical questioning, new ideas, and creative thinking, which could develop students’ core literacy, personality characteristics, and analytical ability, contributing to an active classroom atmosphere and promoting examinations.

Table 3 Propositions of critical thinking attitudes in concept maps

Key terms	Examples of propositions in concept maps
Evidence consciousness	Evidence consciousness requires critical thinking (junior A)
	Critical thinking develops evidence consciousness (junior B, high C)
	Critical thinking promotes evidence consciousness (high A, high B)
Problems	Critical thinking generates problems (junior B)
	Critical thinking promotes problem generation (high E)
	Critical thinking promotes problem solving (high B)
	Critical thinking stimulates problems (high C)
Decision making	Critical thinking guides decision making (junior E)
	Critical thinking affects decision making (high E)
	Critical thinking contributes to decision making (high C)
	Critical thinking contributes to decision making (high A)
Teaching evaluation	Critical thinking promotes teaching evaluation (junior B)
	Critical thinking promotes self-criticism (high E)
	Critical thinking contributes to teaching evaluation (junior C)
Logic and systematicness	Critical thinking develops logic and systematicness (junior E)
	Critical thinking promotes logic and systematicness (high A, high B)
Critical questioning	Critical questioning requires critical thinking (junior A)
	Critical thinking contributes to critical questioning (high E)
New ideas	Critical thinking generates new ideas (junior B, high D)
Core literacy	Critical thinking develops core literacy (junior B)
	Critical thinking affects core literacy (high D)
Analysis	Critical thinking contributes to analysis (high A)
	Critical thinking promotes analysis (high B)
Active classroom atmosphere	Critical thinking promotes an active classroom atmosphere (high A)
	Critical thinking affects the active classroom atmosphere (high D)
Education development	Critical thinking promotes examination systems
Personality characteristics	Critical thinking develops personality characteristics
Curriculum objectives	Critical thinking affects curriculum objectives (high D)
Creative thinking	Critical thinking produces creative thinking (high D)

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It should be noted that not all propositions have a positive attitude towards critical thinking. Individual teachers choose connectives such as ‘affect’ and ‘produce’ to express their neutral attitude towards the interaction between critical thinking and some fields. For example, the junior B teacher put forward ‘critical thinking produces problems’ in the concept map and pointed out in the interview that ‘students with critical thinking can produce more problems, but they need rules and boundaries. If they use critical thinking to raise some irregular and boundless problems, especially those problems that have no research value or meaningless, it will hinder students’ cognitive process and play a negative role’. The high D teacher put forward the proposition ‘critical thinking affects teaching objectives, core literacy, and active classroom atmosphere’. In the interview, the teacher expressed that ‘using critical thinking properly can promote students’ meaningful learning. If critical thinking promotes students’ consciousness to be too divergent, it will have a certain negative effect on the classroom atmosphere and the achievement of teaching objectives’.

Factors affecting the development of students’ critical thinking

Based on the concept maps and interview data, the study found that students’ environmental factors, students’ own conditions, teachers, evaluation methods, discipline characteristics, knowledge types, etc., will affect the development of students’ critical thinking.

Surrounding environmental factors. This mainly includes the family atmosphere, the classroom atmosphere, and peer influence. In the interview, three teachers proposed that students’ families affect their critical thinking development. The high D teacher pointed out that ‘a loose and democratic family atmosphere will make children more confident, curious about things, and like to ask questions, which will definitely have a positive impact on the development of students’ critical thinking’. Seven teachers constructed the proposition of an ‘active classroom atmosphere promotes critical thinking’ in the concept map. An active and relaxed classroom atmosphere with equal teacher–student relationships can mobilise students’ learning enthusiasm, make students dare to put forward new ideas, and then promote students to develop critical thinking.

It should be noted that the junior B teacher constructed the proposition of ‘critical thinking needs rules and boundaries’. She emphasised that ‘we should grasp the activity of the classroom atmosphere. An active classroom atmosphere is conducive to the development of students’ critical thinking, but the overactive classroom atmosphere and students’ excessive divergence of thinking may affect the achievement of the main goals of the classroom’. In addition, two teachers mentioned in the interview the companion students associate with; that is, their circle of friends will affect their critical thinking.

Students’ own conditions. Six teachers considered that students’ own conditions would affect the development of critical thinking. These conditions mainly included students’ existing cognitive level, their own ability and intelligence, students’ cognitive style, students’ personality characteristics, etc. Four teachers pointed out that students’ cognitive style will affect the development of critical thinking, ‘if students like thinking and asking why about everything, their critical thinking will be stronger’. Three teachers considered that students’ existing knowledge and experience would affect their level and perspective of understanding things. ‘If students have rich existing knowledge and experience, their perspective of looking at problems will be more comprehensive and diverse and they will treat problems with a developmental and critical perspective, thus their level of critical thinking will also be affected’. Five teachers put forward the proposition of ‘personality characteristics affect critical thinking’ in the concept map. Think aloud shows that cheerful and lively students tend to be more active in critical thinking.

Teachers. In the interview, the ten teachers pointed out that teachers have a positive and important role in students’ development of critical thinking. Teachers’ teaching ability, knowledge reserve, teaching experience, teaching habits, teaching methods and personality characteristics will affect the development of students’ critical thinking. The junior B teacher considered that ‘if teachers have enough experience, they will anticipate the direction of the classroom and pay attention to enlightening students’ thinking in the process of classroom teaching’. Teachers who encourage students to ask more questions, exchange and express their ideas, be good at guiding students, and interact and dialogue with students are more conducive to developing students’ critical thinking. The junior D teacher pointed out that ‘in the classroom of authoritative teachers, teacher–student interaction is less and relatively quiet. Teachers are more open and democratic, the classroom is more active, and students are also very active in answering questions, critical thinking is easy to develop’.

Evaluation methods. The evaluation method restricts the development of students’ critical thinking. All ten teachers considered that ‘the examination system restricts the teaching and development of students’ critical thinking’. On the one hand, the baton effect of the examination system still exists. If we pay too much attention to the development of critical thinking in teaching, it will affect the overall achievement of classroom teaching goals, affecting students’ examination results.

Conversely, the junior C teacher pointed out that ‘at this stage, junior high school chemistry in many cities in China has become a hierarchical discipline and students’ enthusiasm for chemistry learning has decreased significantly. To some extent, it will cause students to be lazy to think and unwilling to take the time to question and criticise’. How to teach and develop students’ critical thinking under these two situations’ educational systems is worth thinking deeply and researching.

Discipline characteristics and knowledge types. Four teachers considered that ‘discipline characteristics affect the development of critical thinking’. The level of critical thinking cultivated by different disciplines is different. Two teachers proposed that chemistry was a subject based on experiments and that chemistry was conducive to the development of students’ critical thinking. The high B teacher proposed that the type of knowledge will also affect the teaching of students’ critical thinking; for example, ‘chemical experiments are conducive to the development of students’ critical thinking; to a certain extent, factual knowledge is closely related to daily life, and then students will raise some critical questions; on the contrary, theoretical knowledge is relatively obscure, and then students rarely have critical questions and thoughts’. Two teachers also pointed out that because of the spiral arrangement and teaching of knowledge, high school students will find that some knowledge is not completely consistent with what they learned in junior high school, and they will raise some questions.

Teaching practice of developing students’ critical thinking

The survey results showed that all ten teachers considered that critical thinking could be taught and some measures and ways could be taken to develop and cultivate students’ critical thinking in teaching. Specifically, the ten teachers had in-depth exchanges on this issue from the two levels of curriculum and classroom.

Curriculum level. The junior A teacher and junior B teacher clearly constructed the conceptual proposition of ‘critical thinking in curriculum development’. In the interview, six teachers believed that the diversification of different chemistry curricula was conducive to developing students’ critical thinking. For example, the junior B teacher mentioned that ‘we will let students study themes of chemistry elective curricula in Grade 7. The theme of this year's elective curriculum is ‘we need chemistry’ and it mainly introduces science popularisation or chemistry in the form of documentaries. Teachers explain and expand accordingly, so students can reflect on their existing ideas’. The junior A teacher proposed that setting up the approach curriculum in Grade 7 and Grade 8 can not only help students improve their enthusiasm for chemistry and prepare for the formal opening of chemistry in Grade 9 but also increase students’ connection and thinking about chemistry and social life, to develop critical thinking well. The high C and E teachers considered that the current high school chemistry curriculum advocates the creation of real problem situations and guides students to pay attention to the social problems related to chemistry faced by mankind (such as social science issues). These curriculum contents play a positive role in cultivating students’ critical thinking.

Classroom level. The ten teachers mentioned four types of classroom teaching. (1) Experimental teaching. Seven teachers considered that experimental teaching, especially the conscious guidance and reflection in each step of experimental exploration, could promote students’ critical thinking. The junior B teacher discussed this aspect most. She proposed that guiding students to reflect on the links of ‘the scientificity and feasibility of setting up experiments’, ‘the rigour of language in the process of expression and communication’, and ‘reflection and evaluation, summary and communication’ is helpful to cultivate students’ critical thinking. At the same time, the junior E and high C teachers also agreed with using the ‘reflection and evaluation’ link to cultivate students’ critical thinking. The junior A teacher considered that cultivating students’ consciousness of active inquiry, highlighting students’ dominant position, and letting students conduct experiments could promote the development of critical thinking. (2) Project teaching. In the interview, six teachers mentioned the terms project teaching, project-based learning, micro projects, and so on. Teachers said that students would be exposed to a lot of information in the process of participating in real project task solving and carrying out group cooperative learning and critical thinking in analysing and processing information to produce innovative ideas. The high A teacher pointed out that ‘at the end of each unit of the high school textbook, there is a column of micro projects. Students can reason based on evidence, think critically and design solutions based on the observation of reality by learning these micro projects’. (3) Problem solving teaching. The process of problem solving is also the process of students’ critical questioning and judgement based on evidence. Five teachers made it clear that the development of critical thinking was inseparable from problem solving. Problems can not only mobilise students’ enthusiasm and interest in learning but also trigger students’ judgement and evaluation of knowledge, break through the shackles of authority, and promote the cultivation of critical thinking. The junior C teacher said, ‘the creation of problem situation should be combined with production and social problems and highlight the conflict with actual knowledge and experience. Classroom teaching should be problem-oriented rather than asking questions to solve problems’. Two teachers emphasised the importance of ‘teacher setting problems’ and ‘teachers causing students to ask questions’. Teachers should constantly accumulate teaching experience and knowledge, grasp the generative problems in the classroom, and guide students to solve problems rather than directly tell students the answers. (4) Chemistry history teaching. Three teachers considered that the teaching process of chemical history could arouse students’ reflection and cultivate the consciousness of critical questioning. For example, the junior A teacher proposed that ‘the discovery history of atoms, phlogiston theory and other chemical history can make students understand the essence of science and realise that only through continuous exploration and critical questioning can they be closer to the truth’. At the same time, the high D teacher mentioned Haeckel's law of recapitulation: biological ontogeny repeats the history of race occurrence. To a certain extent, this implies that students’ scientific inquiry process will also have some consistency or similarity with scientists’ inquiry experience. Therefore, the teaching of chemical history can enable students to experience the development of science following the footprints of scientists and then experience critical thinking deeply and constantly reflect on their own cognition.

Factors affecting the development of teachers’ critical thinking

Critical thinking can be taught, so teachers’ consciousness and critical thinking skills will have an important impact on the development of students’ critical thinking. All ten teachers expressed that teachers themselves were essential factors affecting the development of teachers’ critical thinking, such as teachers’ consciousness of critical thinking, teachers’ understanding of critical thinking theoretical knowledge, teachers’ teaching experience, teachers’ professional knowledge, teachers’ consciousness of reflection, and teachers’ personality characteristics. For example, the junior B teacher considered that ‘theory is the basis of practice. Only after the teachers learn the theoretical knowledge of critical thinking can they consciously and meaningfully develop their critical thinking. Critical thinking will also be affected by the depth of its own professional knowledge. After in-depth understanding of certain knowledge, critical thinking will develop better’. The high A teacher considered that ‘a cheerful, lively and curious teacher is more willing to try to analyse problems and conduct critical questioning’.

Six teachers mentioned that the school environment, the atmosphere of the teaching and research group, and the students’ needs for development would affect the development of their critical thinking. That is, the environment in which teachers live will affect the development of their critical thinking. The junior A teacher considered that if school leaders are conscious of the importance of critical thinking and the school undertakes projects related to the development of critical thinking, teachers’ development and consciousness of critical thinking will be mobilised. At the same time, the interaction between teachers and research projects’ groups with a strong teaching and research atmosphere is more conducive to teachers’ development of critical thinking. As the high C teacher said, ‘in the weekly teaching and research activities, teachers often discuss how to present the teaching content and how to choose the teaching method. We also often conduct critical questioning about the design of some contents or topics in the book. The process of communicating with experienced teachers and learning more is also a process of developing their critical thinking’. In addition, two teachers mentioned that ‘teaching others teaches yourself’, and students’ development needs will promote the growth of teachers’ critical thinking.

Ways to develop teachers’ critical thinking in teaching

The factors that affect the development of teachers’ critical thinking are also good starting points for teachers to develop critical thinking in teaching. First of all, teachers should keep learning for their lifetime. This includes learning critical thinking theory, deepening professional knowledge continuously, improving knowledge reserves, and enriching the cognition of things and the perspective of analysing and examining problems. For example, the high A teacher stated that one should ‘keep reading and learning and broaden the scope of knowledge constantly, the more we know, the easier we are to promote understanding of things, find problems, correct mistakes and examine problems critically’.

Secondly, reflection is an important way for teachers to develop critical thinking. Six teachers considered that ‘reflection promotes critical thinking’. For example, the high D teacher put forward that ‘reflecting on whether the teaching process and behaviour are reasonable, whether the teaching design is in line with the development of core literacy and whether the organisation reflects students’ subjectivity are conducive to the development of teachers’ critical thinking’. The junior A teacher considered that it was also important to reflect on the content of the textbook, reflect whether the content of the textbook is in line with students’ cognitive development and whether there is a better and more appropriate plan, etc. Thirdly, teachers should improve their consciousness of problems and develop their consciousness of critical thinking. Teachers should prepare lessons, teach, and reflect on their teaching process with problems, to promote their development. The high B teacher considered that ‘problems trigger thinking, urge teachers to look for evidence, enhance their consciousness of evidence, make judgements and decisions and develop critical thinking’. The junior B teacher considered that ‘students’ questions and students’ feedback after teaching can trigger teachers to think and explore’.

In addition, teachers should actively participate in the teaching and research activities organised by the school. The junior B teacher considered that ‘at present, critical thinking mainly exists in the teaching activities of schools in an infiltration or implicit way, and there are few teaching and research activities with the theme of developing critical thinking’. To some extent, it shows the teacher's demands for the training theme of critical thinking. At the same time, the teacher also said that ‘I learned a little about critical thinking during college, and I feel that there is a connection between critical thinking, logical thinking and creative thinking’. This also shows that it is necessary to design and implement relevant critical thinking curricula or cultivate the critical thinking of pre-service chemistry teachers consciously in higher normal education.

Limitations

This study has some limitations. First, only ten teachers participated in the survey in this study. Although these ten teachers come from schools in different regions of China and have different ages, professional titles, and educational qualifications, they meet the representativeness of the sampling to a certain extent, but the sample size is a limitation. People's understanding of critical thinking will have different performances and divergences in different cultures. Therefore, their views may not represent those of the whole group of teachers. However, despite this, we are convinced that the teachers involved in the study have excellent reference values and deserve in-depth consideration for their understanding and ideas of critical thinking based on the perspective of middle school chemistry teaching.

Second, through the test, this study used the restrictive concept map as a core tool for simultaneously detecting teachers’ understanding of critical thinking based on the existing literature and experts’ suggestions. This restrictive concept map provides a scaffold for teachers to answer to a certain extent, which is conducive to activating teachers’ thinking and better stimulating teachers to participate in the drawing of the concept map and think aloud, but the prompt words given may have a certain implication and influence on teachers’ answers.

Finally, with any qualitative study, we must acknowledge that our interpretations are our own and contextual (Bowen et al., 2022). The CGT recognises that researchers’ themes and subsequent theories or frameworks are jointly constructed with participants (Charmaz, 2014). Therefore, investigators will have a certain impact on the research process. Despite this, we still try our best to ensure the reliability and effectiveness of the research and ensure the rigour of the research.

Conclusions

This study explored the perspectives of ten Chinese middle school chemistry teachers on critical thinking using concept maps, thinking aloud, and in-depth interviews based on concept maps. The results and conclusions are based on responses from the ten participants, whose views may not be representative of the entire faculty. Nonetheless, we believe that this study has significant implications for the teaching and development of critical thinking. Specifically, we draw the following conclusions.

First, on the whole, the middle school chemistry teachers who participated in the survey have a relatively extensive and rich understanding of critical thinking, and can better connect critical thinking with other concept nodes and teaching practice. Almost all the teachers who participated in the study believe that critical thinking means reflection and critical questioning, which requires evidence consciousness. This is consistent with Dewey's initial ‘reflective thinking’ (Dewey, 1910) and aligns with the consensus of researchers on critical thinking based on evidence and the processing of information (Facione, 1990a). Teachers have expressed their positive attitude towards critical thinking and believe that critical thinking plays an important role in promoting evidence consciousness, problem solving, decision-making, teaching evaluation, logic, and systematisation. However, some teachers are cautious about the interaction between critical thinking and some fields and believe that teachers should grasp the degree of teaching critical thinking. Otherwise, it may lead to the extreme contrary to the core of teaching objectives to pursue critical thinking. In addition to consensus understanding, teachers of different genders, teaching ages, and educational backgrounds have different existing knowledge and experience, so there are also some differences in their understanding of critical thinking. In particular, the longer the teaching age of chemistry teachers, the more they can accumulate rich teaching experience and have a deeper understanding of critical thinking, especially the practice of critical thinking in teaching. Teachers with higher academic qualifications will have richer thinking cultivation and knowledge reserves, and their scientific research level will be improved correspondingly, which is more conducive to the development of teachers’ understanding of critical thinking. The understanding is relatively wide and deep. To a certain extent, this shows that the experience accumulated in long-term teaching practice and higher education learning can promote the development of teachers’ critical thinking.

Second, factors that influence the development of students’ and teachers’ critical thinking can be derived based on the responses of the ten teachers. The factors that affect the development of students’ critical thinking mainly include the following aspects: environmental factors, including the family atmosphere, the classroom atmosphere, and peer influence; students’ existing cognitive level, their own ability and intelligence, students’ cognitive style, students’ personality characteristics, and other self-factors; teachers’ teaching ability, knowledge reserve, teaching experience, teaching habits, teaching methods and personality characteristics which are influenced by teachers themselves; whether to pay attention to the examination and evaluation methods of critical thinking; characteristics of chemistry and different types of knowledge. The main factors that affect the development of teachers’ critical thinking mainly include teachers’ consciousness of critical thinking, teachers’ understanding of critical thinking theoretical knowledge, teachers’ teaching experience, teachers’ professional knowledge, teachers’ consciousness of reflection, teachers’ personality characteristics and other factors from teachers themselves; the school environment, the teaching and research group atmosphere, and students’ development needs. From the above comparison of influencing factors, it can also be seen that teachers and students promote the development of critical thinking in both directions. Teachers need to teach students to develop critical thinking. At the same time, students’ demand for critical thinking will also encourage teachers to learn and develop critical thinking constantly.

Third, the ten teachers believe that critical thinking can be taught, and students’ critical thinking can be developed and cultivated through certain measures and ways of teaching. At the curriculum level, diversification of different types of chemistry curricula, such as elective and approach curricula, is conducive to the development of students’ critical thinking. The controversial theme of the curriculum based on the real situation is more likely to lead students to think critically, which is also consistent with the existing research (Tiwari et al., 2006; Chase et al., 2017). At the classroom teaching level, experimental teaching, project teaching, problem solving teaching, chemical history teaching, and so on are more conducive to the development of students’ critical thinking. Teachers should keep researching and learning about critical thinking, improve problem consciousness, reflect more, participate in various teaching and research activities actively, and improve their consciousness and ability of critical thinking constantly.

Implications

Critical thinking is a universal human phenomenon and a common thinking heritage of mankind. Critical thinking belongs to all mankind (Facione, 2006). Therefore, teaching and developing students’ critical thinking is an important goal of school education. However, although the importance of critical thinking in chemistry and science education has been recognised, a recognised definition has not been established so far and many resources start from the working definition (Ryan, 2022). Many studies have explored the understanding of critical thinking of different groups and made a purposeful and evidence-based inquiry into what critical thinking is, which just shows that we are using our best critical thinking to think about critical thinking. Teachers play a key role in the cultivation of students’ critical thinking. This study explores the understanding and practice of Chinese middle school chemistry teachers on critical thinking from the perspective of middle school chemistry teachers. It not only provides a methodology for probing individual subjective thoughts but also has the following implications for teaching critical thinking and teachers’ professional development.

Implications for the teaching of critical thinking

Chemistry is a natural science based on experiments. The tentative nature of science (Lederman, 1992) contains the existence of critical thinking. Therefore, we believe that the unique discipline characteristics of chemistry and the learning of different knowledge types can also promote the development of students’ critical thinking well. As an important factor affecting the development of students’ critical thinking, teachers should create opportunities for students to develop critical thinking from all aspects. They should pay attention to the personality characteristics and thinking abilities of different students, create a chemistry classroom with equal dialogue between teachers and students, encourage students to ask questions actively, reason and think based on evidence, and keep a warm and positive attitude towards students’ questions or learning difficulties; based on students’ existing cognitive experience, we should carry out teaching and integrate the development of critical thinking into chemistry classroom teaching, create problem situations that are real and related to social production and life closely, explore the materials that can permeate critical thinking in different chemistry topics, combine the specific chemistry curriculum content, carry out more experimental teaching, project teaching, problem solving teaching, chemistry history teaching, and so on, guide students to carry out purposeful and evidence-based exploration, and develop curriculum themes or unit teaching for critical thinking improvement. At the same time, education that pays attention to the improvement of students’ core literacy emphasises the development of students’ critical thinking, so teachers should find a balance and leverage point in the teaching of evaluation and critical thinking. Irrespective of the way or approach of teaching, we should all insist that teachers give more guidance and students think more so that students can experience and develop critical thinking ‘in doing’, to realise the importance of critical thinking, rather than only staying at the level of concept or cognition.

Implications for teachers’ professional development

As the guide of students’ learning, teachers play the role of models and examples. Developing students’ critical thinking requires teachers to pay attention to their development. Teachers should improve their consciousness and skills of critical thinking, maintain lifelong learning, communicate and reflect more with colleagues and students, participate in chemical teaching and research activities actively, broaden their horizons and accumulate chemical teaching experience constantly. Schools should strengthen the training of the teaching theory and practical knowledge of critical thinking, improve the evaluation system of teachers, and provide system and policy guarantees for teachers to invest in critical thinking teaching. At the same time, the study found that the higher the academic qualifications of teachers, the more the teachers would be inclined to have critical thinking, and the deeper the theoretical understanding of critical thinking they would have. This also provides ideas and inspiration for the training of pre-service teachers and the training of normal students in teachers colleges and universities. Teachers colleges should pay attention to the cultivation of pre-service teachers’ thinking ability and scientific research ability by setting up curricula related to critical thinking and organising normal students to carry out activities related to critical thinking and pre-service teachers can consciously cultivate their understanding of critical thinking.

Conflicts of interest

There are no conflicts to declare.

Appendix 1. Concept map tool for critical thinking

Dear teacher,

Thank you for taking your valuable time to participate in the survey on “understanding of critical thinking of middle school chemistry teachers”. This survey was completed to investigate your understanding of critical thinking through a concept map. Before the beginning of the survey, we will provide you with an explanation of what the concept map is and an introduction and example of how to create a concept map. The answer results are only for academic research, and it will take approximately 30 minutes to complete. There is no right or wrong answer, and your real idea is the best answer.

Part I. Brief description of concept map

A concept map is a structured two-dimensional representation of knowledge resources, information or ideas about a topic. The concept map network comprises terms (concepts), and meaningful relationships are generated between terms through connectives. Two connected terms produce a proposition. Therefore, the concept map mainly includes three elements: nodes, connections and connectives. For example, the standard concept map of “oxidant” can be drawn as follows:

Note: The connection without arrow defaults to the generic relationship from top to bottom; the direction of arrow shall be indicated for other connection relations.

Part II. Construction of concept map

This study aims to investigate your understanding of critical thinking, including but not limited to your knowledge, attitude, views, factors affecting the development of critical thinking, practice in chemistry teaching, etc.

Please construct a concept map with “critical thinking” as the central word. The nodes and connectives for reference are given below. You can use any of them, modify or add some new nodes and connectives and add relevant examples to illustrate.

The nodes for reference: critical thinking, analysis, decision making, logic and systematization, interpretation of information, core literacy, curriculum objectives, examination system, curriculum, teachers, students, personality characteristics, active classroom atmosphere, problems, critical questioning, evidence consciousness, social and teaching environment, knowledge, teaching practice, reflection, teaching evaluation, cognitive process, rules and boundaries, new ideas.

The connectives for reference: promote, contribute, need, contain, affect, be affected by, develop, mean, promote to solve, restrict, reflect, produce, produce in, teach, guide, exceed, learn, appear in, be a part of, for example, have, improve, create, depends on, solve by.

Acknowledgements

This research was sponsored by a project of the Ministry of Education Youth Project of the National Educational Science Planning Foundation of China, which is titled Research on the Role Reconstruction of Primary and Secondary School Teachers in the Age of Artificial Intelligence (EHA220540).

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