Abstract:

Cataldi et al. (2013) describe simulation as a tool for decision making, since it allows the analysis and evaluation of objects, situations or phenomena that due to their complexity, cost or danger would not be possible to do in a traditional learning space. In (Alvarado et al., 2017) a teaching-learning sequence is described, planned and implemented in the classroom and the laboratory, to support the understanding of acid-base chemistry; in the laboratory session, the pH value of samples of various daily products was explored experimentally and how it varies when diluted with water, as well as an interactive pH simulator with the same purpose. In that paper, the authors note the advantages of testing different conditions of the phenomenon without the need for additional resources and the possibility of testing hypotheses about the relationship of pH and concentration, but emphasize that the simulator is a complement to the experimental activity.

On the other hand, Augmented Reality (AR) allows the integration of digital content with information from the real world. In the education field, the advantages of using it for the teaching of abstract concepts, objects or phenomena that cannot be observed with the naked eye have been identified, or to model situations that a student could not repeat, either because of the dangerous nature of the materials or the high cost of them. The AR can enrich the educational experiences of the students, because it allows a more flexible, intuitive and interactive manipulation of the object of study; this can be seen clearly in the teaching of medicine, where AR is used as a tool to develop skills related to surgery, in this case students manipulate physical objects to simulate surgical activities. Another potential advantage of the RA in the teaching-learning process mediated by physical objects, would be in the case of the activities that are carried out in the laboratories of teaching experimental sciences.

This paper proposes the development and use of an application based on AR to support the teaching of acid-base chemistry at the high school level, especially for the understanding of the relationship between pH and the concentration of acidic, basic and neutral aqueous solutions. The objective of this application is to explore "experimentally" the pH value of various daily products (chicken broth, blood, among others) and to observe how this value varies when diluted with water, using tangible elements (a beaker and an Erlenmeyer flask) instead of just virtual objects as in a simulator. The daily products (solutes) and the water (solvent) are simulated by the mobile application and the experimental activity is carried out by manipulating the beaker and the flask as if real products were used. To measure the pH of the products, a wooden stick with a rectangular mark that is printed and stuck on its end is used, the user inserts this object in the container and sees on the screen of the device the pH associated with the diluted solution.

With this type of proposal it is expected that, interacting with AR, the student mobilizes the same cognitive resources as when performing the activity with real objects, focusing on the object of learning without the mediating object being relevant.

Keywords:

PH simulation, augmented reality, tangible interaction, pH-concentration, teaching-learning sequence.