The analysis of academic literature confirmed the advantages of case studies in cognitive development of students, but in it we did not find evidence for the ability of students to identify environmental problems in their surroundings and to use case studies for their solution. In the study we directed students to look for human negative impacts on their local environment and use these observations for formulating problems and for development of original solutions. Students from two secondary experimental schools – one professional and the other language school, were involved in the experimental design and performance. Students made lists of human impacts on their close environment and selected five of them that are most common and threatening. Two groups, one from each school, discussed the five cases, looked for solutions, prepared and presented posters with their results. Other two groups, again one from each school, also discussed the five cases, prepared scenarios of role plays, and presented them to the school audience. Ecological knowledge was assessed before and after the study. Students’ skills for poster and role play presentations were assessed using prepared beforehand check lists with students’ participation. The results showed the critical observation of students and their ability to distinguish between right and wrong in human environmental behaviour. They proved the positive effect of interactive teaching using case studies and discussions, role playing and poster preparation and presentation. They pointed out the difficulties which students met in the process of skill development, and the scaffolding they needed from the teacher.