Temporal evolution of production and citation

The scientific production in curriculum and science in Latin America has remained stable during the last five years, with an average of 19 articles per year (figure 1). The research interest in the area is constant, either due to the permanence of research teams or to the absence of junctures that might lead to a decrease of publications.

Figure 1 Frequency of annual production and citation 

Regarding the citation of documents as a quantitative element of research impact, a total of 103 citations are found (table 1), with a maximum of citation in 2019 (54). Citations are concentrated in a total of 42 articles. The research project by ^{Hurst et al. (2019)} is the most cited (14). It is worth mentioning that the author team belongs to institutions in the United Kingdom, the Netherlands, Spain, South Africa, Argentina, and Mexico. That article presents the results of the study of perspectives and trends on chemical education with a sustainable approach with emphasis on systems thinking.

Table 1. Production and citation descriptions

Note. Citation frequency refers to documents published in WoS. Citation data were taken on August 22, 2021. The clarification is made given the changing nature of citation frequency.

Production by country and international collaboration

Although the criterion for inclusion of the texts was authorship by researchers belonging to Latin American institutions, given the international collaboration of the studies, the statistics show authorship from, for example, the United States, Australia, Germany, and Spain (figure 2).

Note. This figure was made based on data from the Biblioshiny software. The percentage was obtained from the sum of authorship by country (131).

Figure 2 Map of international collaboration. 

The joint authorship between researchers from different institutions shows networks for the exchange of knowledge and perspectives: 15.7% of the documents analyzed are the result of joint studies that include non-Latin American authors; and 66.6% of them include a researcher from Latin America as corresponding author, which shows that most of the teams have been from the region with international support.

On the other hand, it stands out that, of the 84.21% of research with Latin American authors, 95% do not have any international link, meaning that the exchange of knowledge and international networks in the area has been reduced. Articles with joint authorship between Cuba and Colombia (^{Avendaño & Álvarez, 2019}; González & Martínez, ²⁰¹⁹; ^{Pérez & Carballosa, 2018}) and Cuba and Mexico (^{Pino & Filenko, 2017}) stand out within the remaining 5%.

Bradford's law

Bradford's law indicates that if the elements of a set of journals are ordered in a decreasing order, in relation to the number of articles on an object under study, it is possible to show the core of journals dedicated to the subject of study, i. e., there is an unequal distribution in which approximately 20% of the journals produce 80% of the documentary corpus (^{Urbizagástegui, 1996}). Figure 3 shows the production zones. It should be noted that the journals consolidated as a production nucleus can be a reference for the state of the art on natural sciences curriculum.

Figure 3 Productivity nuclei according to Bradford's law 

Co-occurrences

The recognition of thematic groupings in the field of curriculum in natural sciences allows evidencing the research trends that mobilize, transform, or configure the scientific field. For this reason, the analysis of clusters is used. From the mapping of the frequency and joint appearance of key words, the so-called co-occurrences are constructed: "maps that provide a visual representation of the structure of a field" (^{Eck, 2011}, p. 68).

For the consolidation of the map, words with a frequency greater than or equal to three were included, with which the co-occurrence matrix of size 27 x 27 is configured (figure 4). It is elementary that the descriptors curriculum, education, and science have relevance in the co-word map; however, the connections with technology, rural education, conceptions, knowledge, and philosophy are highlighted.

Note. This figure was made based on the data provided by the VosViwer software.

Figure 4 Co-word analysis 

Alongside the statistical groupings consolidated with the key words, a thematic grouping was made in four categories to carry out the interpretative approach of research trends in curriculum and natural sciences.

Conceptions of science

In this research project, there is an interest in the teachers' conception of science. Although the curricular approaches determine theories and topics to be addressed at school, the teacher in the classroom modifies and transposes these concepts based on their beliefs and conceptions.

Biological evolution, for example, is a theory that, even with scientific consensus, is a topic presented in a reserved manner in biological sciences curricula (^{Luvison, 2020}; ^{Tavares & Bobrowski, 2018}). In this sense, ^{Silva and Mortimer (2020)} conducted an analysis in southern countries on the conception of biological evolution of biology teachers. The concepts of origin of life, Homo Sapiens, and evolution and its relationship with religious beliefs were investigated. Although the conceptions and biases are varied, a conflict between the religious and the scientific is recognized, which has influenced the biology class and implies an effort to improve the teaching of biological evolution in the tension between religious cosmogony and scientific evidence, in an analytical and critical sense of biological science.

^{Luvison (2020)} proposes a pluralistic evolutionary worldview as a dialogue between empirical biology, theoretical biology, and philosophy of biology to avoid simplifying the study of evolution and to generate teaching processes and curricular practices in accordance with the 21st century.

However, the curriculum is not only influenced by the conception of a specific theory such as evolution in biology. The notion of science is determinant as a framework on which teaching is based. In that regard, ^{González and Martínez (2019)} propose the development of the curriculum from the science, technology, and society approach. They seek to recognize that development and scientific knowledge are related to technological innovations that respond to social problems of a community, which includes economic, environmental, and political components.

Teacher training

The modernization processes of a country entail political and economic transformations that, in a certain sense, seek the strengthening of human resources. Therefore, the training of science teachers arises as a response to these processes related to industrialization, development, and urbanization. For the Colombian case, for example, the curricular reform relative to the training of science teachers is related to the insufficiency of teachers prepared for the specificity of the area of natural sciences (^{Serrato, 2020}).

For their part, curricular policies, besides seeking to respond to the social movements of a nation, are producers of a type of student and teacher. Between theory and practice there are tensions, dichotomies, and interweavings since the decision of how to teach is permeated by the discourses that give a standpoint in the face of reality and by experience, but also respond to the guidelines and theories that suggest "what is good" in a teaching practice. For the case of science teacher training, in the relationship between theory and practice, there is a tendency to approach the scientific practice to teaching practice, that is, the path followed in teaching and scientific learning must approach the processes that lead to the generation of knowledge itself of science but, at the same time, distance is taken in the recognition that the learning process has to do with a school culture rather than with the development of science (^{Ferreira et al., 2016}).

In that context, teacher training does not only respond to theoretical approaches in university courses. It has to do with a constant process, with daily experiences that allow the teacher to reflect on his own work (^{Rodrigues et al., 2020}). There must be an incessant questioning in which the conditions and responses of students are analyzed, and in which methodological possibilities for scientific learning are drawn. Teacher training is not only responsibility of the state or of higher education institutions but is part of the own daily processes of the teacher as a trainer of themself (^{Bedin & Pino, 2018}).

However, although the teacher is continuously trained in his daily exercise, the curriculum of the university programs of teaching natural sciences must have a strong practical component that is configured "as a moment of development of capacities, abilities, and skills, implying the construction of new knowledge in the face of action" (^{Rodrigues, 2018}, p. 1457). In this way, they will have the spaces to relate the theoretical to the practical prior to their teacher internship.

Interculturality

The flexibility of the curriculum in natural sciences implies involving social and cultural issues of the subjects in training. Therefore, whether in the development of curricula or in class decisions, linking ancestral knowledge specific to each culture is necessary, besides considering ethnic and cognitive diversity and gender issues, which make up the complex universe of the classroom.

For an indigenous community, for example, nature, flora, and fauna have different meanings other than a biological object of study. Nature indissoluble symbiotic relationships are established and go beyond the simple use of resources. They consider that there are gods, souls, companions, and allies of life in nature. In consequence, curriculum development in these environments should not move away from those interests and knowledge, because in addition to being a factor for the loss of traditions and customs, it discourage the study of natural sciences in indigenous students (^{Acosta, 2016}). Similarly, popular knowledge can be part of science teaching, as a space for the possibility of inserting the intercultural into the classroom with topics such as: medicinal herbs and their impact on the human organism, traditional foods, processes of conservation and treatment of food, or environmental pollution in the management of crops or mining (^{Avendaño & Álvarez, 2019}).

Likewise, the particularities of students with some type of cognitive or physical disability should be considered in the natural sciences classroom, so that the student is neither relegated in the experiments brought to class nor in the activities of approaching a certain scientific notion, since inclusion is assumed as a process that goes beyond the physical presence in the classroom (^{Taverna et al., 2019}).

Didactic content knowledge (DCK)

The experience of natural sciences teachers has been investigated from the components of the DCK: purpose of teaching a certain topic or issue; difficulties that students will have; curriculum; instructional strategies and content representations; evaluation; the teaching context; and didactics of the discipline (^{Melo et al., 2016}). In that sense, ^{Goes et al. (2020)} found that teachers with more experience perform activities oriented to the application of disciplinary content, while novice teachers focus on content instruction.

Language and orality

Reading, writing, and oral skills are important in the teaching of natural sciences since they are part of the way of representing the processes and characteristics of phenomena. Therefore, beyond learning the contents of the area, the teacher should strive for the development of these skills (^{Candela, 2020}), so that, besides promoting the learning of disciplinary knowledge, the discursive skills with which scientific knowledge is generated and circulated are developed (^{Andueza, 2016}).

Similarly, bilingualism is an important factor in the teaching and learning of science since knowledge of the English language, for example, allows the opening to discourses and research in science and technology so that the conceptual knowledge available in the native language can be expanded, complemented, or enriched (^{Apa-Terrero et al., 2019}; ^{Archila & Truscott, 2020}).

Application of science in the real world

The interaction and observation of real-world objects and phenomena can be the focus of science teaching. Getting students to conduct inquiry, prediction, and explanation of scientific events has its basis in the interaction with real problems (^{Batista-Freyre et al., 2016}; ^{Candela, 2020}). Project work is a methodological strategy based on this perspective (^{Pérez & Carballosa, 2018}). On this basis ^{Garcês et al. (2018)} present an experience in the teaching of biochemistry through the methodology of problem-based learning, where three joint projects were developed on diabetes, hypothyroidism, and lactose intolerance in order to generate learning about metabolic diseases. Besides the acquisition of knowledge on the subject, the experience allowed teamwork and the development of communication skills in writing and orality, along with the approach and reflection on the problems of contemporary society.

Scientific investigation

The development of activities that allow the student to follow the steps of scientific research enables the learning of scientific knowledge. Activities that lead from initial reflection and prediction, through observation and data collection, to interpretation and analysis, allow students to develop a personal scientific experience that enables the development of skills in natural sciences (^{Parra et al., 2018}, ^{Silva & Galembeck, 2017}).

Under this perspective, ^{Parra et al. (2018}) present the sequence of a class of RC Circuits, in which an experimentation exercise is performed. This consisted of the assembly of the circuit, taking voltage and current reading, the elaboration of tables and graphs from the data collected, and the preparation of a descriptive report on the work done. The activity allowed the student to become familiar with RC circuits prior to the theoretical instruction of it. In this way it was possible to improve the learning of the students evidenced is their grades.

Use of information and communication technologies (ICT)

The use of ICT in the classroom has evidenced a positive relationship with learning since they allow, beyond the visualization of content, the monitoring and control of experiments (^{Luca et al., 2017}). Regarding visualization, educational videos are a resource that transcends the physical space of the classroom and can be used without limit of space or time. In this sense, ^{Vera et al. (2019)} made educational videos on "chemical equations" that were edited and published as a complement to class activities. Thus, students had unlimited explanations from the teacher for the approach of different exercises and problems.

For their part, ^{Soares et al. (2018)} opted for the use of a multimedia game to contribute to the teaching of natural sciences. The authors conclude that the digital educational resource combines the potential of the game for promoting inquiry, wonder, and debate based on the interest of young people in the use of digital devices, which enables the learning of scientific content.