Context-based learning has become increasingly influential in science education over the last 40 years. However, it is still unclear which types of contexts foster students' interests and learning achievements and are appropriate for science classes. While contexts are usually selected by teachers or curriculum developers, this study focusses on the students' perspective. The central aim of this research project is to analyse which context students choose for their science learning and why they choose a specific context. Therefore, a questionnaire study has been conducted in German grammar schools. The data analysis illustrates that students choose significantly different contexts depending on their individual variables like gender or individual interest in the subject. Additionally, it is possible to identify different reasons for selecting a specific context in chemistry. When comparing students' individual variables, significant relations between students' individual interest as well as their last grades in chemistry and their motives for choosing a context can be found. A cluster analysis has produced three clusters for describing students' explanation patterns for selecting a context. Overall, the results of this study allow first conclusions about the question which types of contexts ought to be implemented in science classes for specific groups of students.