When discussing the topic "Hunger in Africa" with students, incorrect and biased ideas on the causes for hunger are revealed. In order to change the students' personal concepts it is necessary to become acquainted with their mental models. Therefore, a survey of Geography students' different personal theories concerning "Hunger in Africa" was carried out. By means of interviews followed by concept mapping, the various personal theories were identified. It became apparent that the students mostly rely on climate and the population growth as arguments to explain the occurrence of hunger in Africa. The greatest difference between the personal and the scientific theories was that the students included almost no external influences, whether economic or political, in their explanations but relied mostly on factors within a country when formulating their statements. The research literature commonly suggests that there are three steps in reshaping learners' "misconceptions". The first is to make the present views explicitly the subject of the discussion. At this point the experiences that led to these views should be reflected on and newly interpreted. Second, the newly acquired knowledge must prove itself when used in certain contexts. Finally, during the process, a cooperative culture of learning must prevail, where the learner is convinced that he can control his own acquisition of knowledge. On the basis of these insights, teaching aids were developed that allow students to check their own personal concepts, to dismiss them and to align them with scientific concepts. (Contains 3 figures.)