International Baccalaureate Diploma Programme is two year pre-university course of study designed for students in the 16 to 19 age range. Although inquiry-based chemistry curriculum promotes the model of discovery learning, actual chemical instruction does not always follow the stated model; quite often, it is only lecture-based not paying enough attention to the international dimensions of scientific problems and a variety of approaches science works through, to produce explanations. At the outset we considered the following theoretical framework: (1) According to Hodson (1998), engaging in the processes of chemistry changes student's conceptual understanding as processes and concepts are interdependent. Therefore, students should understand procedural knowledge to the extent that they can use it themselves and evaluate whether it has been used appropriately. To achieve this, learning should be embedded in an authentic and meaningful activity. (2) Increasingly, there is a recognition that many scientific problems are international in nature and this has led to a global approach to research in many areas. Where appropriate within certain topics, international aspects of scientific problems and problem-solving approaches should serve for developing context-dependent learning experiences in terms of achieving a more global understanding of basic chemistry notions.

To investigate the acquiring of context-dependent learning experience and its influence on the level of knowledge required in higher level chemistry exam, the international environmental problem on ozone depletion was selected as a case example. The study was carried out in the academic year 2006/2007 and involved three groups of ten higher level chemistry students and the same teacher. The predicted grade of each group was approximately the same (5/6 (out of 7)). To implement environmental topic into chemistry teaching, it was necessary to concentrate on aspects that would give students a tool to recognize chemical problem(s) and to know where to find data, how to analyze and use them to solve problem(s). In this way particular content becomes a context in which critical skills should be developed. Comparative analysis of chemistry syllabus and knowledge on ozone depletion accessible in different sources enabled the identification of chemistry concepts (bond energy term, free-radical substitution reaction, degradability of CFC)) which could be learned by means of ozone depletion. In the case study, the first and the second group of students acquired knowledge on chemistry concepts stated above in a traditional problem-solving approach; in the second group ozone depletion problems served as context-dependent learning environment. In the third group, students acquired knowledge more actively in terms of recognizing patterns of knowledge (constuction of concept maps) in context-dependent learning environment. At the end, all students wrote a test consisting of IBO Chemistry Higher Level Paper 2 questions on key chemistry notions as pertaining to the topic. The test applied contained several short-answer questions, one data-based and one extended-response question. The part of the last question went partly beyond the content objectives of the syllabus since it transposed the knowledge gained to ozone depletion as international environmental problem.

The comparison of the level of achievement of three case study groups demonstrated by quality of students' answers (at the test) confirms the premise that context-dependent learning experiences of students could significantly increase the quality of responses of higher taxonomy levels (synthesis, evaluation). On the other hand, the shift from traditional problem-solving approach to a more student-centered instruction in terms of students' recognizing patterns of knowledge is what does not lead significantly to a more global understanding of selected chemistry notions, if students learn in context-depending learning environment.