Abstract:

We present the development of Didactic Guides (DG's), to aid in the solution of problems that arise when considering the teaching-learning process of Chemistry in Higher Secondary Education in Mexico. This process presents various conceptual, procedural and attitudinal issues.

The teaching work not only requires mastery of the contents of the subject but also requires that the teacher possess pedagogical knowledge. This knowledge is generally obtained and learned by reading articles from specialized magazines on education, by participating in academic events such as congresses, courses, or workshops; they are activities that for various reasons, teachers do not generally do.

DG's are developed on various topics of Chemistry in the HSE, as documents addressed to teachers, which offer them information of interest in a practical way.

Each DG "is not a substitute for the textbook, nor is it a manual", it is a complementary tool that provides the teacher with didactic and disciplinary resources challenging to find in conventional textbooks. The DG consists of a compilation of information (resulting from an extensive search and analysis of various documents such as articles, books, theses), and of various Practical Works (PW's). These PW 's are conceived as any teaching-learning activity that involves students in the observation or manipulation of objects and materials (or representations of these) being studied (Millar, 2004), and which were developed, applied and explicitly evaluated for DG.

Several DG's are being developed each addressing acids and bases at the macroscopic level, another one with Arrhenius theory and yet another with Brønsted-Lowry theory. Other DG's addresses strength and concentration of acids and bases; minerals; amino acids and proteins; even one corresponding to the simple pendulum.

The structure of each DG conforms to that described by Alvarado (2012), as shown below:
- Introduction.
- Concept map on the subject.
- Some of the essential statements involved.
- Historical aspects.
- Importance of their learning.
- Background knowledge and skills required for their learning.
- Conceptual, procedural and attitudinal difficulties in their teaching-learning process and suggested contributions to minimize them.
- Examples of PW to develop.
- Suggestions for the test and evaluation of the learning of the subject and, particularly, of the PW.
- Some important specific concepts to support the development of the PW.
- Annexes.
- References and bibliography.

This manuscript presents examples of the content of the DG "Acids and bases at macroscopic level" and "Strength and concentration of acids and bases", and conclusions after application in the classroom.

References:
[1] Alvarado, C. (2012). Secuencias de enseñanza-aprendizaje sobre acidez y basicidad, a partir del Conocimiento Didáctico del Contenido de profesores de Bachillerato con experiencia docente. Tesis Doctoral, Universidad de Extremadura, España
[2]Millar, R. (2004). The Role of Practical Work in the Teaching and Learning of Science. Paper prepared for the Committee: High School Science Laboratories: Role and Vision, National Academy of Sciences, Washington, DC., October.

Keywords:

Didactic Guides, Chemistry, Higher Secondary Education, Practical Works.