Abstract:

Phenomena associated with acids and bases are extremely important in Nature, and also in many fields of human activity (laboratory, industry and environment). To develop education for the future, it is mandatory to consider the role of technologies by integrating resources in classroom or lab actions, trying to simulate the impact that ICT are having within social and industrial conditions. So now it is the time to plan education with an ICT component by which acid rain, stomach acidity or antacids can be simulated and interacted with students.

With the aim of developing a teaching/learning experimental chemistry sequence, in this work a research is presented with a constructivist focus, based on:
1) Pedagogical Content Knowledge, documented by Loughran et al (2004) «Content Representation» framework of ten experienced Mexican teachers of High Scholl and College level. It was necessary to learn more about their knowledge, beliefs, teaching strategies, experiences, attitudes, habits, creativity and innovation, context and reality;
2) Elicitation and taking into account learning troubles and alternative conceptions documented for 388 Mexican High School students with the application of an experimental laboratory practice, with the help of Technology, and a diagnostic assessment two-tier questionnaire (Treagust, 1995);
3) Analysis of the acids and bases content of eight textbooks authorized by the Public Education Ministry of the Junior High School level.

A main purpose of this study is to transfer results to the classroom or laboratory, to support teaching activities of ordinary teachers at high school level, through the construction of didactic guides, videos, presentations, interactive software, linking with books or papers reading, biographies and conceptual maps. In particular, Google Docs shared documents were used by means of a spread sheet design to promote modeling, discussion and collaboration among students.

One of the sequences will be described thoroughly. Its name is “Depending on the frog’s size is the stone throwing”, with the purposes:
a) Close students to the chemical reactivity concept and its relation with acid concentration;
b) Foster the identification that reactivity is not a simple linear relation on concentration.
The experimental activity was carried out with 27 pupils (organized in teams of 3 to 4 students each; 16-17 years old) of a High School of the National University of Mexico, in an ICT equipped lab-classroom (with computers and software for supporting the teacher). The starting point was the hypothetical analysis of the attack of different concentrations of hydrochloric acid on the aluminum sheet, followed by modeling the election of one of four graphs of concentration vs. time in a shared spread sheet and justifying and giving arguments on their election. The experimental activity was then developed, drawing up the corresponding graph and answering a set of six questions over the same phenomenon, but observed on line. The teacher had the way to monitor the entire computer keyboarding of the students.

It has to be highlighted three main incidents related with the activity performance:
a) Pupils’ confusion on the nature of the bubbles formed (air, water vapor, oxygen, hydrogen chloride and hydrogen were mentioned);
b) Two of the teams referred they were watching a physical change;
c) Three teams wrongly predicted that increasing acid concentration will increase the time to make a hole on the sheet.

Keywords:

Acids and bases, ICT in an experimental sequence, Google docs, Pedagogical Content Knowledge, Alternative Conceptions.