A Deus e ao Espírito Santo, que sempre me concederam livramento, saúde e discernimento. Obrigado meu Pai, pelas bênçãos infinitas! A professora Daniela, que além de orientadora, é uma pessoa muito amiga, amada e que sempre fez parte da minha vida acadêmica e particular. Obrigado por ser tão especial! Obrigado por toda a orientação, paciência, dedicação e comprometimento. Obrigado pelos momentos de "rabo de foguete", que me fizeram amadurecer muito. A professora Yassuko Iamamoto, também orientadora e muito querida, que me abrigou em seu laboratório e disponibilizou a disciplina de Química Analítica Qualitativa (QAQ) para que nossa pesquisa fosse desenvolvida. Obrigado por toda a orientação e pelos ensinamentos de uma pessoa sensível e experiente. A banca do exame de qualificação, professoras Elaine Araújo e Joana de Andrade pela leitura minuciosa e contribuições importantes para o nosso trabalho. Aos alunos das IX, X e XI turma de Licenciatura em Química do DQ/FFCLRP. Ao Fabrício Bortolucci Zanardi, grande amigo, companheiro de laboratório e que contribuiu com as filmagens dos encontros. Ao Isaltino Alves Barbosa, monitor de QAQ, companheiro de laboratório, de disciplinas da pós, grande amigo que tive a oportunidade de cultivar. Obrigado por todo auxílio, conselhos e maturidade exemplar. A Renata Bernardo Araújo, também monitora de QAQ, companheira de disciplinas da póse que compartilhou conosco a pesquisa em Ensino de Química.Obrigado pela amizade que construímose que ela possa perdurar! Que venham os próximos desafios (doutoramento). Aos colegas de laboratório Douglas e Lucas Zanatta, pelo companheirismo e pela amizade. Aos meus pais, Rosendo Maya Sanchez e Luzia Moreira Sanchez. Obrigado pelo imenso amor, carinho, dedicação e compreensão. Vocês sempre serão minha inspiração. São grandes exemplos de honestidade, hombridade, caráter e de como um pai deve criar um filho. Amo muito vocês.

Preto to contribute to science education, especially of teens in the region of Ribeirão Preto. This Center enables the promotion of various events like the Olympiad of Chemistry, school visits to the University, offering workshops for high school students and teachers. In all activities, information and formative concepts are discussed with participants. The students of chemistry who act as monitors have the opportunity to collaborate in organization and in implementation of activities and may broaden their education. This project promotes continuous dissemination of science, which we think is important for the formation of citizens. The activities, not only benefit the High School students who could learn about the University and Chemistry as a science and profession, but also provided a space for the initial training of teachers.

As the Distance Education (DE) becomes more popular many course are being offered in the on-line version, including Science degree courses. In previous papers, based on Leontiev's Activity Theory, we developed Teaching Guiding Activities (TGAs) about the indentification-separation of heavy metals and investigated the potential of these TGAs as a theoretical-methodological proposal in a face-to-face Chemistry Teaching course. The researcher's regular face-to-face Chemistry degree and his work as a monitor in the Distance Education course at São Paulo University helped defining this paper central question: in Distance Education, how would a TA engage students toward the learning of chemical knowledge ? The theoretical bases of this paper are the works developed by Vigotski, Leontiev and Engeström. The methodology used was the qualitative research, with focus on the Microgenetic Analysis. The empirical field was the on-line discussion forums, where the TAs were available. The TA/forum was developed with distance education students from 7 different cities in São Paulo State. When planning the TA-DE (TGA for the Distance Education), we focused on not having experimental practices as it is common in face-to-face courses because the student would be alone during the activity and would not have many laboratory resources. We could notice that in the distance activity the student-student interaction was not satisfactory as the participants would interact with the researcher/professor. The results made it evident that in the 8 groups, in which the TA was developed, several words appeared on the subjects studied, directly or indirectly, and that in the system of analysis carried out pointed to important processes of conceptual elaboration, some concepts were developed, some were questioned and/or refuted. At the face-to-face education the TA development would be analyzed mostly from the individual perspective and we believe that this characteristic was kept at the Distance Education. However, social-historical information or experiences were shown more during the development of the distance TA than in the face-to-face one.