Description: The communication of current scientific topics with societal relevance to young people is of great importance in order to prepare them adequately for present and future life and to provide them with a solid basis for a sustainable development of society. The scientific, didactic and technical demands for communicating such complex topics in an authentic learning environment in a way that is appropriate to the subject matter and the target audience pose great challenges for scientists and educators allone. This doctoral thesis therefore presents the interdisciplinary development and evaluation of two out-reach activities for secondary grade students in a student laboratory. The students worked out the effects of future changes in the Baltic Sea with hands-on experiments and an interactive computer simulation. Computer simulations and experiments are important learning methods in modern sci-ence education. However, existing research has not sufficiently identified the educational and di-dactical advantages and disadvantages of both methods and often lacks appropriate comparability. The effects of the methods were investigated on knowledge gain, situational interest and beliefs about science first in a direct comparison (NStudy I = 443) and second in a combined approach (NStudy II = 367). The comparative study showed that a simulation conveyed more content knowledge and experi-ments caused higher situational interest. The combined approach indicated that two methods con-veyed more knowledge than one, and the combination of the two methods positively influenced the perceptions of scientific predictions. The results also showed that the students had a fundamentally high level of trust in science. Combinations of experiments and simulation can contribute to a comprehensive understanding of, and interest in com-plex current issues in science, and combine the potential of both media and methods.

Description: Interactive computer simulations and hands-on experiments are important teaching methods in modern science education. Especially for the communication of complex current topics with social relevance (socioscientific issues), suitable methods in science education are of great importance. However, previous studies could not sufficiently clarify the educational advantages and disadvantages of both methods and often lack adequate comparability. This paper presents two studies of direct comparisons of hands-on experiments and interactive computer simulations as learning tools in science education for secondary school students in two different learning locations (Study I: school; Study II: student laboratory). Using a simple experimental research design with type of learning location as between-subjects factor (NStudy I = 443, NStudy II = 367), these studies compare working on computer simulations versus experiments in terms of knowledge achievement, development of situational interest and cognitive load. Independent of the learning location, the results showed higher learning success for students working on computer simulations than while working on experiments, despite higher cognitive load. However, working on experiments promoted situational interest more than computer simulations (especially the epistemic and value-related component). We stated that simulations might be particularly suitable for teaching complex topics. The findings reviewed in this paper moreover imply that working with one method may complement and supplement the weaknesses of the other. We conclude that that the most effective way to communicate complex current research topics might be a combination of both methods. These conclusions derive a contribution to successful modern science education in school and out-of-school learning contexts

Description: Sedimentary ancient DNA (sedaDNA) has proven to be a useful tool for palaeoenvironmental studies, but only a handful of studies exist so far for tropical regions. In this study we used sedaDNA to study the temporal succession of Brachionus spp. rotifer mitochondrial DNA haplotypes using two sediment cores from two climatically different alkaline-saline crater lakes from the Kenyan Rift Valley. Data were retrieved from a sediment core (dating back to AD 1800) from Lake Kageinya, located in the remote, hot and hyper-arid Suguta Valley. sedaDNA was used to study the temporal succession of mitochondrial DNA haplotypes of Brachionus spp. rotifers. The results were compared to previously published data from Lake Sonachi, a well-studied lake in the humid and colder mountainous region of Kenya near the town of Naivasha, now supported by a 210Pb age chronology. Both records extend back before the onset of substantial anthropogenic impact in these regions. The results revealed that climate—rather than anthropogenic impact—was most strongly correlated with haplotype changes in both lakes. During prolonged dry periods (such as from AD 1910 to the late AD 1960s), certain haplotypes persisted. Sudden changes and the emergence of alter native haplotypes were observed when climate became more humid or during episodes of highly variable climate (before AD 1910 and from AD 1960s onwards). Progressive changes in prevailing haplotypes during periods with variable climate could reflect local adaptation and/or be the result of immigration of new haplotypes after the eradication of previous populations during extreme environmental conditions (high temperatures, UV irradiation, pH and salinity). The results indicate that, despite adverse chemical conditions, sedaDNA in tropical lake sediments is preserved for at least a few hundred years. Therefore, its analysis provides a useful complementary palaeoenvironmental proxy for palaeolimnological reconstructions and novel insights on changes in rotifer populations through time.