The contribution of networks of concepts in understanding the learning of the subject of chemical equilibrium in University Education.

Author(s)

Erika Reyes Molina

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Física (IF/SBI)
• Defense date: 2024-10-08

Examining board members

Leila Soares Marques; Marly Babinski; Daniel Marcos Bonotto; Joselene de Oliveira; Fernando Brenha Ribeiro

• Advisor: Leila Soares Marques

Abstract

In recent decades, studies on the cognitive structure of students have mentioned that learning can be understood as the reorganization of the relationships between concepts in semantic memory, in which new knowledge structures are built through the introduction of new concepts, which relate to existing ones, making the cognitive structure more coherent and comprehensive. Thus, a technique that can help in understanding the learning process is the semantic network, or network of concepts, which shows how certain human knowledge is structured by means of the concepts evoked in spoken and/or written discourse, from different stimuli or perspectives, offering an empirical means of accessing the cognitive organization of knowledge. Under this model, information expressed in text form is coded into words/concepts and then organized into a numerical matrix, which allows for the creation of a graphic network representation, in which the terms make up the vertices of this network and are joined together by lines, according to the relationships established between them, making up the edges that unite them. The corpus of this study comprises written texts on four questions proposed before and after instruction, by students (bachelor\'s and undergraduate) starting an undergraduate degree in Chemistry at night, in response to open questions, followed by a list of structuring concepts on the subject of chemical equilibrium, applied in the subject of General Chemistry II (2nd semester of the course), in order to verify the extent to which the inducing concepts and others not provided are used by the students, through the frequency of use of these terms. These networks were constructed both for each individual student\'s answer and for all the answers together, in order to obtain a network containing information from the whole group. In order to understand the networks developed, a set of network analysis metrics were evaluated, which helped to understand the dynamics of the relationships existing in the networks studied. These metrics refer both to the properties of vertices (concepts) and edges (relationships between concepts), by analyzing the most related pairs of concepts, extracting the semantic meaning of these links from the texts. The topic of chemical equilibrium was selected because, in addition to its abstract nature, it links other topics such as chemical reaction, reversibility of reactions, kinetics and thermodynamics. The aim of this project was to use network modelling to understand how students organize the concepts of chemical equilibrium during their undergraduate course. The results show that the application of the metrics detected central nodes in the network, which seem to indicate that it is around them that students structure their knowledge of chemical equilibrium. (AU)