Problem-based learning (PBL) is an acclaimed educational concept for laboratory teaching in chemistry, which significantly affects learner motivation. A central aim of PBL is to overcome educational problems with "cook-book" laboratories. For example, when students receive experimental instructions and apply the instructions similar to recipes, they do not necessarily understand what they do and why. However, research in problem-based laboratories still produces inconsistent and even contrasting results. A reason for this is the research focus; the problem-based concept and the outcome (e.g., learning results) are often investigated without considering the implementation of the problem. According to self-determination theory (SDT), it is necessary for problem-based learning to invoke a sense of autonomy, competence, and relatedness in the students to foster intrinsic learner motivation. To understand better the mechanisms and potential of PBL in enhancing intrinsic motivation, it is pivotal to investigate and identify connections to the practical implementation. This study focuses on intrinsic motivation connected to implementation. The aim was to clarify central implementation strategies for PBL concepts that enhance intrinsic learner motivation. To this end, we conducted semistructured interviews with undergraduate, nonmajor chemistry students who attended an innovative, industry-based PBL-laboratory course and analyzed them using qualitative content analysis. The results suggest central implementation factors that are interconnected and led to a novel model of the autonomous scientific process. The factors that enhance intrinsic motivation in this model are the independent acquisition of information, the design and application of the experimental procedure, the gathering of feedback through experiments, and the possibility to optimize the process. Adequate strategies must be taught to the students to enable autonomy and are exemplified in this study. The students perceived the presented industry-based problem setup as an authentic, autonomous scientific process, thus appealing to their self-perception as scientists.
Der Beitrag stellt eine alltags‐ und problemorientierte Lerngelegenheit vor. Das Werbeversprechen „Aspirin® – so schnell wie nie, dank MicroAktiv‐Technologie“ wird durch Einsatz eines schultauglichen Modells einer pharmazeutischen „Basket‐Apparatur“ und der Photometrie mit Hilfe des Smartphones schulexperimentell überprüft und sachgerecht bewertet.
The focus in teaching and research is shifting from a traditional perspective of information literacy (IL) as a specific set of general, mostly text-based skills to a more comprehensive understanding of the complex aspects that constitute IL as an ongoing, contextspecific process. However, there is a need for further insight into the social and contextual dimension of the information process. The inherent connection between problem-based learning (PBL) and IL holds great potential for a better understanding of students' information experience. The aim of this study was to describe the contextual and social aspects of the information process students engage in during a PBL beginner's lab and how this practical experience can be utilized for teaching. To this end, a wide range of qualitative data were collected over the course of three cohorts, including interviews, on-site audio recordings, and documents. Results suggest that students first evaluate the information they retrieve in terms of experimental safety, feasibility, and usefulness in planning the experimental procedure. Then, the experiment provides the crucial information about whether the previously acquired information was useful for solving the problem. The experiment is at the center of the student information process in a PBL lab. In this work, we discuss how to organize IL instruction from the student perspective and thus place the experiment at the center of IL instruction in a PBL lab. The results of this work contribute to an expanded understanding of IL that is useful for teaching and research in chemistry education.
In school chemistry, the oxyhydrogen
or “Knallgas”
reaction is used to provide evidence of hydrogen gas in the squeaky
pop test. However, the test actually indicates the presence of an
explosive gas mixture of hydrogen and oxygen (oxyhydrogen gas) rather
than pure hydrogen. The sheer observations of an explosive reaction
and the formation of a condensing reaction product, which can be detected
as water, are not sufficient to call the squeaky pop test a clear
and specific test for hydrogen. These observations can also be made
by burning gaseous hydrocarbons with stoichiometric amounts of oxygen,
contradicting the assumption that the gas present in the reaction
vessel is a mixture of hydrogen and oxygen. For a reliable detection
of hydrogen, this article presents the preparation of a heterogeneous
catalytic system which facilitates a specific and unambiguous hydrogen
test in chemistry classes by using a redox dye for the clearly visible
indication of hydrogen: the Heterogeneous Catalyzed Hydrogen Test
(HeCHT). The catalyst can be synthesized easily and safely due to
the low hazard potentials of the reactants and products. Furthermore,
the preparation of the test reagent is inexpensive, and the reagent
can be reused.
Die Entwicklung neuer Arzneistoffe ist ein mit Blick auf den Gymnasialunterricht möglicher Kontext mit hohem Lebensweltbezug. Ein Lehrexperiment, basierend auf dem käuflich erhältlichen Modell‐Zielmolekül Trypsin und mehreren Inhibitoren, ist mit in der Schule verfügbaren Methoden auf einfache und robuste Weise durchführbar. Es verdeutlicht den Kern des rationalen Wirkstoffdesigns (rational drug design), nämlich die planvolle Variation der molekularen Struktur zur Erhöhung der Bindungsaffinität an die Substituenten in der Bindetasche des Zielmoleküls, durch Erhöhung der Summe an intermolekularen Wechselwirkungen. Somit wird für Schülerinnen und Schüler nachvollziehbar, wie genau neue Arzneimittel auf molekularer Ebene erdacht bzw. erarbeitet werden.
Zusammenfassung: Im Experimentalunterricht wird dieheterogene Katalyse ofta mE xperimentd er oszillierenden Verpuffung einesM ethanol-Luftgemisches an einem Kupfer-o derP latindraht vorgestellt. Dieses Experiment wird seit etwa 30 Jahren vonv erschiedenen Autor:innen weiterentwickelt.J edochbirgt dieV erwendungvon Methanoli ndiesemExperimente inigeG efahren,daunabhängig vond essent oxischer Wirkungb ei der Reaktion Methanal entsteht.A ufgrundd er Gefahreneinstufungen vonM ethanolu nd Methanal istd ie Durchführungd iesesE xperimen-tesimChemieunterrichtals kritisch zu bewerten.Indiesem Beitragwirdnun durchRückgriffauf einenhistorischenErkenntnisstandz ur heterogen-katalytischenW irkung des Platinse in neuartiger Schulversuch zuro szillierendenR eaktion vonAlkanen mitLuftsauerstoffvorgestellt.Die Verwendungv on haushaltsüblichemW aschbenzin ermçglicht dieD urchführunga ls Schülerexperimenta bd er 4. Klasse undvereinfacht dieHandhabung desV ersuchs.
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