https://repositorio.ufu.br/handle/123456789/5166 Tue, 21 Jul 2026 03:11:44 GMT 2026-07-21T03:11:44Z https://repositorio.ufu.br/handle/123456789/48888 Title: Análise da presença de radiações ionizantes em materiais diários utilizando câmara de nuvens Abstract: The cloud chamber is a particle detector that enables the direct visualization, with the naked eye, of the tracks left by ionizing radiation. The objective of this work was the optimization of a thermoelectric cloud chamber prototype already described in the literature, aiming to improve its robustness, safety, and thermal efficiency, for its subsequent application in the qualitative analysis of radioactivity in everyday materials. A visual analysis was carried out on several sources, such as a 232Th electrode, an old alarm clock hand containing 226Ra, uranium glass, and 222Rn. The chamber demonstrated a high capacity to distinguish the visual signatures of α particles (short and dense tracks) and β particles (long and erratic tracks), in addition to background radiation. The analysis allowed the visual demonstration of complex physical concepts, such as secular equilibrium and radioactive decay. Its optimization proved effective for teaching and research in the field of nuclear physics Fri, 06 Feb 2026 00:00:00 GMT https://repositorio.ufu.br/handle/123456789/48888 2026-02-06T00:00:00Z https://repositorio.ufu.br/handle/123456789/48862 Title: Uso de experimentos no ensino das leis de Newton Abstract: Physics teaching has often not attracted or motivated students, with the teaching methodology being one of the factors that contribute to learning difficulties. The use of experiments can be explored as a strategy to awaken students' interest in the subject. This work presents the construction of a didactic sequence (SD) with the theme of Newton's Laws, developed through experiments. The sequence was planned for eight regular 50-minute classes: the first class consists of the application of an initial questionnaire to understand the students' perception of the topic; the following six classes are intended for carrying out and discussing three experiments, one for each Newton's law; and the last class is theoretical in nature, including the reapplication of the questionnaire in order to evaluate learning. Although the sequence has not yet been tested, it is expected, based on studies and observations of pedagogical practices, that it will contribute to improving the teaching and learning of Newton's Laws. Fri, 03 May 2024 00:00:00 GMT https://repositorio.ufu.br/handle/123456789/48862 2024-05-03T00:00:00Z https://repositorio.ufu.br/handle/123456789/48828 Title: Estudo do uso de nanopartículas metálicas (NPM) e filmes finos metálicos em amostras de grãos para o aprimoramento da performance analítica da técnica de Espectroscopia de Emissão Óptica Induzida por Laser (LIBS) Abstract: The agricultural sector is responsible for nearly ¼ of Brazil’s GDP, and consolidates the country as one of the largest producers of food globally. Given this scenario, the need for analysis techniques regarding the composition, which envisions the quality control of grains, is proving to be more and more necessary. Between all of the analytic techniques, the LIBS (Laser Induced Breakdown Spectroscopy) technique has proven to be relevant because of its versatility, ease of application, robustness, multi-element analysis capability, among other benefits. Despite all of the advantages of this technique, there are still many efforts in improving the sensibility of the technique. Improvements, such as double-pulsed LIBS (DP-LIBS), femtosecond LIBS (fs-LIBS), or the use of metallic nanoparticles (NELIBS), have been studied for optimizing, among other parameters, the limit of detection (LOD). The use of metallic nanoparticles, in particular, associated to LIBS (NELIBS) has shown relevant results for the enhancement of the technique. While most of the work in the literature has been focused on metallic, vitreous or ceramics, samples, this work is focused on the use (or incorporation) of metallic nanoparticles, as well as thin metallic films, in grain samples (coffee, corn, sorghum, soy) for the analytic enhancement of LIBS. The best results were achieved using thin gold (Au) films deposited on the surface of the grain samples. Expressive gains in intensity of the atomic lines were observed, in the order of 200% for coffee, 600% for corn, 1500% for sorghum, 600% for soy in selected atomic lines of iron (Fe). This work aims to measure the gain in intensity of the most relevant atomic lines present in the spectrum, and to analyze the possible mechanism that led to this phenomenon, through the investigation of the plasma’s temperature and electron density. The results show an indicative increase in both temperature and plasma density for the samples with deposited nanoparticles, as well as, the ones coated with thin films. Tue, 17 Mar 2026 00:00:00 GMT https://repositorio.ufu.br/handle/123456789/48828 2026-03-17T00:00:00Z https://repositorio.ufu.br/handle/123456789/48822 Title: A experimentação de baixo custo no ensino de Física: uma proposta metodológica para escolas do campo Abstract: The teaching of Physics in rural schools faces challenges related to the lack of infrastructure, the absence of laboratories, and the difficulty of articulating the subject with the students’ reality. In this context, low-cost experimentation emerges as a viable methodological alternative to democratize access to scientific practices, fostering motivation, meaningful learning, and the appreciation of peasant identity. This study aims to propose and analyze the use of low-cost experiments in the teaching of Physics in rural schools, investigating their contributions to students’ motivation and the development of investigative skills. The theoretical framework is based on the contributions of Paulo Freire, Lev Vygotsky, and Alberto Gaspar, highlighting the centrality of dialogue, social interaction, and the affective dimension in the educational process. The research also considers the relationship between school and work in rural areas, discussing the impacts of balancing study and labor activities on students’ school retention and academic performance. The proposed methodology consists of applying three simple experiments, constructed with recyclable and easily accessible materials, over the course of two 40-minute classes, followed by the application of an evaluative questionnaire to verify the clarity of the proposal and the learning outcomes. It is expected that the investigative approach will encourage students’ active participation, promote the articulation between prior knowledge and scientific concepts, and strengthen student protagonism. In addition to contributing to the inclusion and democratization of scientific knowledge, the study intends to provide practical support for teachers working in rural contexts, reaffirming rural schools as spaces of emancipation, dialogue, and collective construction of knowledge. Wed, 18 Mar 2026 00:00:00 GMT https://repositorio.ufu.br/handle/123456789/48822 2026-03-18T00:00:00Z