The introduction of the European Higher Education Area implies a change in the methods involved in the teaching-learning process, as well as in the evaluation techniques used by the teachers. In this context, and considering the widely recognized importance of 'wiki' tools ('wikis' from now on) in teaching, we have used the Computer Supported Collaborative Learning (CSCL) as an on line tool to help the students in learning specific parts of the program of the subject "Atmospheric Pollution". "Atmospheric Pollution" belongs to the curriculum of the degree in "Environmental Sciences" at the University of Granada. It is a compulsory subject which has a high number of students (more than 100).

Our study was developed in several steps: a) first of all, in order to check the interest/motivation of the students, a survey was conducted in which students were asked about their previous experience on 'wiki' environments and collaborative work; b) a practical lesson was given in order to make the students become acquainted with the working principles in a wiki environment; c) the students were informed about the contents (sections) of the 'wiki', the rules they must observe in the creation process as well as the evaluation system; d) the teachers continuously monitored the contributions made by the students and made comments on them if necessary; e) several meetings were periodically held with the students to share ideas and make suggestions on possible improvements; f) final survey to know the opinion of the students on the whole process of the creation of the wiki; g) publication of the contents of the wiki in the repository of the University of Granada.

The results of the initial survey indicate that the students have received the idea of creating a 'wiki' in a very positive way, remarking that "it is an interesting option for developing collaborative tasks" and that "it encourages the students to look for scientific information and to exchange ideas between them". The students also stated that in the traditional work groups there are frequent conflicts due to the unequal task distribution (38.2%), or to the impossibility of combining the schedules of the different members of the group (52.9 %). The majority of the students (67%) said that they have never made a computer supported collaborative work. Up to this moment the students are showing enthusiasm and dedication to the creation of the wiki.