Introduction⁴

To this day, physics content is still taught in a way that does not encourage students to engage in the intellectual process of discovering the natural world and its properties (^{Gleiser, 2000}). On the other hand, there is also a lack of motivation among students to study physics, and even an aversion to this subject (^{Bonadiman & Nonenmacher, 2007}). Physics teaching is predominantly characterized by mechanical memorization of formulas and definitions, due to the existence of correct answers to be reproduced in tests and quizzes. One of the reasons for this is that, from the beginning of primary education, schools function as training centers and teaching is part of a culture of training and testing, with students and teachers focused on tests aligned with preparation for the work market (^{Moreira, 2000}).

The predominant aims of school education in Brazil today are in line with the neoliberal project for education in peripheral countries. In this project, school education is made subordinate to forms of governability through the standardization of results, which seek to regulate the school through productivity factors (^{Pacheco & Marques, 2014}). Within this logic, the aim is to generate percentages and indexes that make it possible to analyze the extent to which Brazilian education is adapting to economic demands. However, teachers and researchers (^{Amorim, Reis, Oliveira, & Santos, 2018}; ^{Oliveira, Veit, & Araújo, 2015}) have made efforts to promote changes in physics teaching, seeking to achieve student learning beyond performance in large-scale tests.

Contrary to this educational project, which has an economic bias and aims to adapt to the capitalist production process, theorists who take the approach of teaching for the human development of students (^{Davýdov, 1982}; ^{Hedegaard & Chaiklin, 2005}) argue that the purpose of school education is to promote the formation of students through the appropriation of concepts, ensuring broad and in-depth learning, with a creative and critical character. These authors understand that students' development is influenced by various aspects of their historical-cultural life context, but in school education, one of the fundamental aspects that favours this development is the preparing for teaching and learning. For them, the way in which teaching is carried out helps them to take on an attitude of investigation and search for an understanding of the object. In this way, students become active subjects in knowledge and learning. The motivation to learn is generated by the type of relationship the student establishes in working with the object of knowledge, within an activity with that object, and by a double movement of concepts, all of which is provided by the way teaching is organized.

The aim of this article is to present the results of a study starting from the assumption that developmental teaching, based on the formulations of ^{Vygotsky (2001}, ²⁰⁰⁷), ^{Davydov (Davýdov, 1982}; ^{Davydov & Márkova, 1987}; ^{Davydov, 1988}), and ^{Hedegaard and Chaiklin (2005}), represents a theoretical-methodological alternative to promote changes in the teaching of physics, particularly in secondary schools. We set out to investigate: what changes can be identified in student learning when teaching is organized based on the principles of these theories? The aim was to assess the degree of change in students' thinking in relation to one physics concept - in this case, the heat concept - which was taught using the theoretical principles of developmental teaching.

Theoretical references

The research was based on the theories of Lev S. Vigotski, Danil B. Elkonin, Vasili V. Davydov, Mariane Hedegaard and Seth Chaiklin. Cultural-historical theory originated in the studies of ^{Vygotsky (2001}, 2007) and was further developed by scientists who followed him. Concepts formulated by this theorist, such as mediation, internalization, the zone of proximal development, the process of concept formation and human activity, were relevant to this research.

^{Vygotsky (2001}) defended the premise that essentially human characteristics are not innate, but are formed from the dialectical relationship between human beings and society and nature, a relationship mediated by culture. In the human being's relationship with other subjects and with nature, historically elaborated and culturally organized knowledge is internalized. What characterizes this relationship is the mediation by historically constructed instruments and signs.

In this way, ^{Vygotsky (2001}, ²⁰⁰⁷) explains that the subject's learning occurs as a social situation, with learning influencing development and the two being interrelated processes. According to the author (^{Vygotsky, 2001}), learning can take place in different social and cultural contexts, implying two different types of knowledge and concepts: everyday (or spontaneous) and scientific (also called academic or scholastic). The course and conditions of development of these concepts are different. Everyday concepts are based on everyday experience, developed from interactions between human beings and between human beings and the world, in the contexts of daily life, forming an intuitive understanding of things, involving the process of relating words to specific objects. These concepts represent a basis for learning scientific concepts. In turn, scientific concepts are elaborated and systematized, as a result of scientifically-based research and reflection, and are learned in formal teaching-learning situations, mainly in school education. The appropriation of scientific knowledge occurs through an institutional educational process, which produces something fundamentally new in the subject's development (^{Vygotsky, 2007}). The author's argument is that these two types of concepts need to be understood from a perspective of dialectical interrelationship. The process of forming scientific concepts involves all the basic psychological functions (attention, memory, abstraction, the ability to compare and differentiate objects), beginning in childhood and extending into adolescence. In order to form concepts, it is necessary to learn to direct one's own mental processes with the help of words and signs (^{Vygotsky, 2007}).

As ^{Vigotski (2007}) saw it, the development of human beings occurs through the process of internalizing culture, which takes place in two distinct moments, called intrapsychological and interpsychological. ^{Pino (2005}), in agreement with this law, explains that children become cultural beings (human beings) as they incorporate culture, based on their actions which are signified by the other people with whom they relate. Everyday concepts and scientific concepts are important, but it is the scientific concepts that enable the formation of a reflective consciousness through cultural mediation.

In school education, another relevant concept from Vygotsky's theory is the zone of proximal development. It is linked to the levels of development, of which there are two. The level of actual development is characterized by activities in which the individual is able to understand and act independently with a given object of knowledge. This level represents development in retrospect and refers to mental functions that have already been formed and to established capacities. The level of potential development, on the other hand, encompasses capacities corresponding to ideal forms of culture and socially elaborated knowledge that can be acquired by the individual. It is a perspective of development to be achieved prospectively, depending on the context of life and the individual. The zone of proximal development lies between these two levels, and is determined by mental functions and capacities that are being formed, but which do not yet allow the individual to act independently; for this reason, it requires guidance, help and collaboration from another more capable person. This zone makes it possible to engineer the subject's immediate future and their dynamic state of development (^{Vygotsky, 2007}).

The theory of developmental teaching (or teaching for human development), as conceived by ^{Davydov (Davýdov, 1982}; ^{Davydov, 1988}, ¹⁹⁹⁹), represents an advance on the studies carried out by previous Russian psychologists and pedagogues belonging to Vygotsky's scientific school. ^{Libâneo and Freitas (2017}) state that the foundations of this theory come from scientific research carried out at School No. 91 in Moscow over a period of 25 years, with the participation of several other theorists, including Elkonin. The latter also theoretically formulated the periodization of human psychic development in the cultural-historical conception, based on Leontiev's theses on the role of activity in the constitution of human consciousness (^{Elkonin, 1987}). His studies established six periods of development, each marked by a main activity that acts as a guide or conductor of development. These are: direct emotional communication activity with adults (0 to 1 year); manipulative object activity (2 to 3 years); play activity (4 to 6 years); learning activity (6 to 10 years); emotional communication activity with peers (adolescence); social production activity - work (adult) (^{Elkonin, 1987}).

Davydov's theory consolidated the theses initially proposed by Vygotsky, but also added the contributions of Elkonin and Leontiev on human development, mediated by the guiding activity in each period. Supported by Vygotsky's thesis that school teaching and learning is the universal means of promoting the process of human development, ^{Davydov (1988}) advanced theoretically in his explanation of the organization of teaching aimed at promoting students' omnilateral human development. Thus, the structure of learning activity was formulated in detail (^{Davydov & Márkova, 1987}). Although this activity ceases to be the guiding activity from adolescence onwards, it still plays a fundamental role as a means of promoting students' development. For ^{Davydov (1988}, p. 130), "[...] the concepts historically formed in society exist objectively in the forms of activity and their results, that is, in rationally created objects". Thus, individuals act with concepts that previously existed in society, acquiring and appropriating them in a process of development and humanization.

It should be noted that while Vygotsky established everyday and scientific concepts, ^{Davydov (Human 1988}) distinguished between two types of scientific concepts, empirical and theoretical, which are formed through empirical thinking and theoretical thinking, respectively. While abstraction and generalization are thought procedures for forming concepts, they have different characteristics in empirical and theoretical thinking, due to the different logics that underlie them, the former being formal logic and the latter dialectical logic.

In empirical thinking, empirical abstractions and generalizations of a logical-formal nature enable students to analyse and compare objects of knowledge, identifying and distinguishing their externally observable attributes that are immediately perceptible by the senses, apparent, similar or different in relation to others, the aspects common to a class, and other aspects that enable comparison, distinction, classification, hierarchization, quantification, etc., associating them with a definition and forming an empirical concept. Empirical concepts are important in terms of the ability to classify, hierarchize, define direct relationships between phenomena, etc. in order to understand facts in their particular form. And Davydov recognizes the contribution of empirical concepts as enabling students to reproduce existing mental and social representations and, in this sense, to learn paths of thought that other people have already followed. However, empirical concepts are insufficient to provide an opportunity for deeper understanding and to encourage the formation of more complex thinking and analytical skills, which is important for the omnilateral formation of the human being. For the author, empirical thinking holds students hostage to these paths, which is why he advocates the primacy of theoretical thinking and theoretical concept formation (^{Davýdov, 1982}; ^{Davydov, 1988}).

In turn, theoretical thinking unveils the essence of the object, through the contradictions between its internal and external properties and relationships with other objects, giving meaning to the concept. "The object of knowledge is no longer reality as it appears to the senses, but reality - the scientific object - constructed by theory, in the subject-object relationship" (^{Borba & Valdemarin, 2010}, p. 30). Thus, "[...] dialectical thinking highlights the passages, the movement, the development, thanks to which it can examine things according to their own nature" (^{Davydov, 1988}, p. 111). It is theoretical thinking that allows the universal forms of things to be reproduced beyond their particular and immediate aspects. This type of thinking reveals the internal properties of the object of study, but in connection with its external properties, in other words, what characterizes the object's reflected and essential mediated existence. Theoretical thinking makes the theoretical concept possible and this, in turn, is a form of "[...] mental activity, by means of which the idealized object and the system of its relations are reproduced, which in their unity reflect the universality or essence of the movement of the material object" (^{Davydov, 1988}, p. 128). Because of its dialectical nature, theoretical thought "[...] highlights the passages, the movement, the development, thanks to which it can examine things according to their own nature" (^{Davydov, 1988}, p. 111). In order to achieve this movement and passage, thought needs to move from the abstract and universal aspect of the object to its concrete and particular aspects, in other words, from the general to the specific. Preparing for teaching through the task of studying an object of knowledge must correspond to this movement, i.e. the method of ascending from the abstract to the concrete and from the general to the specific.

The primacy given by the author to theoretical thinking and concepts is due to the fact that they encourage creative thinking and a gain in autonomy, since they lead students to assume the position of someone who investigates, in a similar way to scientists and researchers; however, not with the aim of scientific discovery, but of appropriating the products of science. The importance given to the theoretical concept is also related to its strong influence on the subjective transformation of students, with repercussions on the formation of their consciousness. In this way, students appropriate the theoretical riches accumulated and expressed by humanity in the form of culture, science, art, ethics, etc. and expressed in concepts (^{Davydov, 1988}, ¹⁹⁹⁹).

Davydov formulated the structure of learning activities by taking into account the elements of human activity established earlier by Leontiev (need, motive, task, actions and operations) and included desire, believing that need alone is not always enough to engage students in studying the object. The learning activity is intentionally planned by the teacher in order to present students with a real problem to be solved, with the solution being found along the way. The learning activity enable students to identify a general and universal relationship and, using this, to analyze particular aspects of the object, forming a comprehensive understanding of it. To do this, the teacher needs to carry out an in-depth analysis of the object in order to identify the universal and abstract relationship that characterizes the object. In this analysis, it is necessary to go to the genesis of the object and understand its development and transformation within the area of knowledge up to its most current constitution (^{Davydov, 1988}, ¹⁹⁹⁹).

^{Hedegaard and Chaiklin (2005}) concluded that Davydov failed to consider a very important aspect in his theory that influences school learning: students' socio-cultural practices. Thus, in the theory of radical-local teaching, these authors describe them, proposing to articulate practices experienced by students on a personal, local and social level with the scientific knowledge to be learned in a given subject, which accentuates the students' motivation for learning. Methodologically, this articulation occurs through what the authors call a double movement in teaching: on the one hand, the teacher moves from the scientific concept to the students' sociocultural experience; on the other, the students move from the sociocultural experience to the scientific concept (^{Hedegaard & Chaiklin, 2005}).

Methodological approach

Research was carried out in the theoretical field of didactics, using the formative didactic experiment, which consists of studying changes in the development of students' mental and practical actions in a real situation, through the influence of intentional didactic actions proposed by the teacher (^{Davýdov, 1982}; ^{Davydov, 1988}; ^{Hedegaard & Chaiklin, 2005}). The researcher considers the development that students can achieve in terms of learning and skill formation within a given subject of study. The method was formulated by Davydov and his team in the context of the Elkonin-Davydov system of teaching, taking shape in school programs and experimental teaching plans (^{Davydov & Márkova, 1987}). It is part of a family of methods devised in Soviet psychology to study the causes, conditions and mechanisms of development through education and teaching (^{Zuckerman, 2011}). It is a method that assumes, as part of the research, a connection between the way teaching is prepared, learning and the formation of concepts by students. It is characterized by the intervention of the researcher in the teaching-learning process with a focus on learning and changes in students' thinking.

The research was carried out at a Federal Institute, located in a city of the state of Goiás, in which 22 students took part, consisting of 14 girls and 8 boys, aged between 16 and 18, and the physics teacher, bringing the total number of participants to 23. The students were enrolled in the 2nd year of high school integrated into one of the technical courses offered by this institution. The teacher had a degree in physics, a master's degree in physics and a doctorate in education, and was familiar with Davydov's theories and those of Hedegaard and Chaiklin. The students were identified as P1 to P22 and the teacher as P.

Preparing to teach certain content in a subject must include knowledge, but not only that, as it is also necessary to include the logical and psychological capacities related to the knowledge that the students are expected to develop during the study of the content (^{Davydov, 1988}). Thus, proposing a formative didactic experiment requires analyzing the concept to be taught and learned, identifying its universal and abstract relationship.

The heat concept was selected to be the object of learning for the students. This choice was justified by the fact that, epistemologically, it is a concept that is linked to others in Physics, in the field of Thermology and Thermodynamics, forming a single, interconnected conceptual system. This content was also chosen because it is considered by students to be difficult to learn, as it is often confused with the thermal sensation of being hot, and its understanding is often expressed through the caloric theory, which was replaced by the scientific physics community in the 1840s (^{Pádua, Pádua, & Silva, 2009}).

In order to prepare for teaching, we first carried out a logical-historical analysis of the heat concept. According to the ^{Davydovian conception (Davýdov, 1982}; Davydov, 1988), this analysis makes it possible to explain the origin of the concept, clarifying the dialectical contradictions that involve overcoming theoretical and epistemological changes, which result in the transformation of the concept and, above all, allow the identification of the abstract universal relationship that underlies it. The logical-historical study of the heat concept made it possible to identify the three main theoretical explanations of this phenomenon: phlogistic, caloric and heat-energy (^{Pádua et al., 2009}).

The aim was to show that these theoretical explanations were formed from the constant investigative work of the researchers, reflecting the transformation of the concept by superimposing one explanation on the foundation of the previous one, in a dialectical process of continuities and ruptures, until we reached the constitution of the heat concept as "[...] a type of energy that is transferred from one body to another, exclusively because of a difference in temperature" (^{Carron & Guimarães, 2006}, p. 266). It is important to emphasize that "[...] matter does not contain heat, it contains molecular kinetic energy and possibly potential energy, 'not heat'" (^{Hewitt, 2002}, p. 270, emphasis added).

This universal relationship was taken as the basis for preparing for the teaching of the heat concept, as proposed in the formative didactic experiment. In doing so, we tried to correspond to the theoretical premise that in order to learn an object, the student needs to form a concept, which requires a method for thinking about it and analyzing it, with reference to the mental path taken by scientists in the construction and discovery of this concept (^{Davýdov, 1982}; ^{Davydov, 1988}). The structure of the lessons is presented in the Results section of this article.

The following instruments were used to collect data: a questionnaire to characterize the students' sociocultural background; a diagnostic task; a semi-structured interview; direct observation of physics classes, before and during the teaching of the heat concept, based on the theoretical framework of developmental teaching; and a round table discussion with the students. The questionnaire and interview with the students covered topics such as the socio-cultural context of their lives, their main activity, the purposes that predominate in their lives, their relationship with their own learning, learning in the subject of Physics, the relationship that the students see between their learning and their development, among others. The semi-structured interview with the teacher covered the following topics: concept (theoretical framework) of training and teaching practice; teaching working conditions. Since it is impossible to present the entire set of data here, for this article we have selected some of the data that we believe to be most significant for the purpose of the text, referring to the diagnostic task, direct observation of the classes and conversations during the round table.

Results

Second action

Having discovered in the first action that there is a universal relationship explaining the concept of heat, in this action the students had to build a model representing this relationship. This model aims to represent this relationship as an essential element of the object being studied, which is often not immediately apparent (^{Freitas, 2012}). Therefore, it is not just a question of indicating the external and apparent characteristics of the phenomenon, but of demonstrating what lies behind the elements of the object that are expressed and which can be immediately perceived.

The model can be expressed through text, graphics, symbols or letters, theatrical representation, etc., as long as it correctly expresses the universal relationship of the object under study (^{Davydov, 1988}; ^{Hedegaard & Chaiklin, 2005}). In this case, the students were asked to draw a picture.

Organized into three groups (G1, G2 and G3), the students formulated and built a model which they thought represented the universal relationship of heat. During the socialization of the groups' models, it was noted that flaws in the model were indications that the universal relationship had not yet been correctly identified or that the model was not sufficiently well constructed. The teacher then asked the students to evaluate the models, analyzing whether they corresponded to what had been asked of them so that they could see any mistakes which, although subtle, mischaracterized the universal relationship. At this point, therefore, the students were carrying out, within the second action, what is defined in the fifth action by ^{Davydov (1988}, ¹⁹⁹⁹) to be carried out transversally in all of them, that is, the conscious, reflective and critical examination of their performance and their progress throughout the actions, with reference to the defined goals. The mistakes which the teacher and students identified and discussed so that they could be corrected were: a) Group G1 represented heat using arrows in the same direction and in both directions, indicating heat transfer from both bodies even though they were at different temperatures. In this case, the correct way to indicate the universal relationship of heat would be to place the arrow unidirectionally, at only one end of the line, indicating that the flow of heat energy occurs spontaneously from the body with the highest to the lowest temperature. b) Group G2 used 'hot and cold' to identify the bodies and the movement of the molecules that make them up. Hot and cold are thermal sensations, so it would be correct to use temperatures T1 and T2. G3 added the physical quantity 'distance' to the relationship. The universal relation of heat can be described as the modality of energy that is transferred from one body to another due exclusively to a difference in temperature, i.e. from the body with the highest temperature to the body with the lowest temperature. The model should be representative of this essential internal connection of the object heat.

They added the moment of thermal equilibrium, with both bodies reaching the same temperature and resulting in the extinction of heat in the system under consideration. Figure 1 shows an example of one of the models constructed and the final model drawn up by everyone.

The relevance of the action of constructing the representative model of the universal relationship of the concept lies in promoting the student's awareness of the reality captured and reproduced by the human mind, highlighting the need for the human mind to recreate it in an ideal form when forming awareness of a real object. This recreation reflects the real object in another form, the form of theoretical thought, which in turn expresses, on an ideal level, the movement of the real object, its contradictions and transformations (^{Davýdov, 1982}; ^{Davydov, 1988}; ^{Hedegaard & Chaiklin, 2005}). Another important role of modeling is that it gives students the opportunity to create and not just reproduce knowledge. Creating the model requires analysis and synthesis, imagination, mental experimentation, which turns the student into a subject who formulates, plans, elaborates representations rather than someone who simply repeats or memorizes. This action helped to make the students aware that, in order to form a theoretical concept of a real phenomenon, a method of analyzing and thinking about this phenomenon is necessary, and it initially requires the procedure of abstracting the universal relationship, which contains its most essential and internal nexus. Thus, at the same time as carrying out the action, the students were also examining their path and their method of thinking, analyzing and grasping the object, which corresponds to the fifth action (described below).

Source: ^{Batistella (2020}, p. 152)

Figure 1 Group G2's model of the universal relationship of the heat concept 

After the discussions and corrections to each model, the students were asked to reach a consensus on the formulation of a single model that expressed two bodies with different temperatures, indicating the movement of energy from the body with the higher to the lower temperature (Figure 2).

Source: ^{Batistella (2020}, p. 156)

Figure 2 Final model of the Universal Relationship of the Heat concept. 

Discussing the results

The aim of the research was to verify the occurrence of changes in high school students' thinking in relation to a physics concept, heat, taught using the theoretical principles of developmental teaching, according to the theoretical framework explained. The results of the diagnostic task provided elements for continuing with the formative didactic experiment, showing that the students either had an empirical scientific concept or an everyday concept about heat, or they didn't have any knowledge of it.

Among the twenty-two students taking part in the research, only one student, P3, showed no change in her knowledge of heat. She explained that she had personal and emotional reasons for not carrying out the learning task and so did not develop the attitude of a subject in a learning activity. It is inferred that with more time, more didactic mediation and an in-depth understanding of this student's motives, she could probably participate and have an investigative attitude like her classmates, and could even form the theoretical concept of heat.

As for the other students, the data presented in the tables indicates that there has been a shift towards the theoretical concept of heat. There were eight (8) students with empirical knowledge. Of these, all reached a theoretical understanding of heat. The students who had signs of an everyday concept of heat were thirteen (13) and they all also formed a theoretical understanding of the concept.

Another change was seen in the students' motivation and participation. By preparing for the teaching, introducing problems that were linked to the students' sociocultural context and local knowledge, there was a positive repercussion that favored the establishment of a relationship with the object of study and, in this way, the realization of the learning activity, which has this relationship as a defining criterion. The students developed the attitude of someone who investigates and wants to discover an explanation for the phenomenon of heat, which is fundamental to forming a theoretical concept and moving beyond the level of just reproducing the concept based on the conclusions of theorists in the field of physics. It was also important to take into account the periodization of the students' development and the activity of simultaneous communication, because, as well as fostering collective and collaborative work, it helped to give the fullfilment of the tasks and the search for a solution to the problem a personal meaning for them.

The preparing for teaching according to Davydov's theory, combined with the double movement in teaching proposed by Hedegaard and Chaiklin, proved to be a promising alternative for teaching the heat concept in high school physics. These theories represent references for developmental didactics in order to realize the perspective of the students' integral formation, the formation of autonomy in learning, creativity in solving life's problems in a social context, the transformation of theoretical concepts into mental procedures to be used in everyday life. In this way, we have a perspective that overcomes the instrumental, pragmatic, reductionist and limiting perspective of student learning and development.

However, it must be stressed that the consistent use of these theories as a didactic foundation for planning and preparing for physics teaching poses challenges for teachers in terms of their capacity for epistemological analysis of the content to be taught and in-depth knowledge of these theories. This theoretical and methodological understanding requires investment in initial and continued training for physics teachers. ^{Silva, Pereira, Novello and Silveira (2018}) state that the majority of teachers are demotivated in relation to their teaching career and, for this reason, there is an urgent need for public policies that promote the valorization of teachers, especially in financial terms, so that they can dedicate more time to their training and lesson planning. The development of dialectical theoretical thinking as a method of thinking about and analyzing an object of study refers to the idea of a subjective process of change in students' psychological capacities, but it is important to consider that, according to Vygotsky (2007), the impact on development is a broader process that cannot be grasped immediately. It is a future-oriented process, which will manifest itself every time the student uses the method of thinking about the concept in other situations and in a way that is integrated with learning the conceptual system of Physics.

Final considerations

Schools today are constantly striving for high-quality teaching, but this search has been dominated by a concept of school performance, expressed in achievement in external assessment tests focused on quantitative measurement of learning. This has led teachers to play a technical role in the teaching-learning process and to fulfill pragmatic educational goals with a neoliberal, market-based bias (^{Menegão, 2016}). As a result, students miss out on the opportunity for a type of learning that promotes their development in a more open and broader way, taking into account their needs for personal and social transformation.

Particularly in the teaching of high school physics, much remains to be achieved in terms of change. In the scientific literature on high school physics teaching, the main problems studied by researchers include learning difficulties (^{Bonadiman & Nonenmacher, 2007}; ^{Menegotto & Rocha Filho, 2008}; ^{Oliveira et al, 2015}; ^{Darroz; Trevisan & Rosa, 2018}), students' lack of interest in learning physics concepts (^{Cima, Rocha Filho, Ferraro, & Lahm, 2017}); the distance between school content and students' daily lives (^{Bonadiman; Nonenmacher, 2007}; ^{Menegotto &; Rocha Filho, 2008}; ^{Sena dos Anjos, Moreira, & Sahelices, 2017}; ^{Cima et al, 2017}); contextualization of physics knowledge (^{Reis & Reis, 2016}; ^{Vizzotto, Mackedanz, & Miranda, 2017}); introduction of teaching strategies and resources to facilitate learning (^{Sousa & Silva, 2014}; ^{Amorim et al., 2018}). This research argues the need for changes in the teaching of Physics, suggesting diversified methodological proposals in order to boost student participation, making them active in the teaching-learning process, as well as creating forms of motivation and involvement with learning.

By agreeing with these researchers, we reaffirm the need for a perspective that goes beyond understanding the purpose of physics teaching, arguing in favor of the theoretical perspective of developmental teaching, which highlights the formation of the dialectical theoretical concept as essential. However, few studies are explicitly based on the concept of teaching for the development of students. For example, based on Vygotsky, there are studies focusing on social interaction between students and the zone of proximal development (^{Monteiro, Monteiro, Germano, & Gaspar, 2010}; ^{Pureza & Magalhães, 2008}), mediation, affectivity and experience (^{Pereira & Abib, 2016}). Based on Davydov, there are studies such as ^{Merengão's (2011}), which focused on the formation of students' mental actions, ^{Brignoni's (2018}), which developed a didactic-formative experiment with high school students to form concepts of light propagation and image formation, and ^{Borges' (2016}), which carried out a didactic-formative experiment in the first year of integrated high school on the content 'Newton's Laws'. Thus, in addition to a few studies, no works were found that incorporated the contributions of Hedegaard and Chaiklin.

In this vast field to be explored, the results of this research can add new contributions to the search for changes in high school physics teaching, strengthening the perspective of teaching to promote the development of students' abilities, through the formation of theoretical thinking of a dialectical nature. This is what was sought in this study, using the heat concept to carry out a formative didactic experiment in secondary education. There is a pedagogical and social need for changes in teaching and learning in high school physics so that students are motivated to learn, feel the desire to understand the concepts of physical phenomena in greater depth, and become capable of using these concepts in general social life and in their local context. Developmental teaching represents an alternative to promote a broader education for students, one that is not restricted to a focus on tests and exams, and that does not reduce their development to neoliberal performance criteria, focused on productivity and adapted to demands that are solely economic in nature.

It is possible to widely explore and make use of the theories of Vygotsky, Davydov, Elkonin, Hedegaard and Chaiklin in order to create a didactic-pedagogical praxis in high school physics teaching, oriented towards a social commitment to promoting transformations in students' cognitive, social, ethical, political and cultural education, helping them to become aware and active subjects in their social and local reality, using theoretical concepts to do so. The results described here, although they cannot be widely generalized to the teaching of physics in secondary schools, provide important clues so that changes can be introduced in the direction of a teaching-learning process that is closer to a creative, critical and conscious formation of adolescents, which allows them to adopt a subject's attitude and move beyond everyday and formal empirical knowledge towards dialectical theoretical knowledge. The main contribution of this research is to empirically show the possibility of developmental teaching as an alternative for teaching physics in secondary schools, in order to boost the quality of students' learning and thus contribute to their education and human development.