The use of ICT in science education offers many opportunities to promote students' learning and experimenting comprehensively. Considering that, it is important not simply to replace traditional media, but to explicitly identify the added value of ICT tools for students and teachers. Especially alternative forms of documenting experiments, particularly video documentation, provide both the possibility to diagnose students' individual learning conditions, abilities and difficulties as well as the opportunity to cope with students' cognitive and epistemological conceptions adequately. Apart from the school context, extracurricular activities (informal learning-settings, like out-of-school lab-days) can be used to explore the potential of video documentations. The following paper presents the use of video documentation as an ICT learning and diagnostic tool in the out-of-school lab "ELKE". Based on a qualitative examination, the video documentations give insight into students' professional and formal strengths and weaknesses - an added value that a traditional experiment protocol is not able to provide in this way.