This book contains working materials that support students in implementing and reflecting on the hypothetico-deductive method of inquiry. Unlike traditional experiment books, this one does not provide a collection of recipes for unconsidered replication; instead, it guides students towards independently exploring an experimental question. Since the required independent experimentation is challenging, various forms of assistance are provided. Each experiment begins with a list of learning objectives. This is followed by a comprehensive informational text that addresses a phenomenon from everyday life and conveys fundamental knowledge about the subject area. Next, the research question is presented along with a list of relevant planning aspects. Generalized and specific work instructions follow, which outline common solution paths. These instructions are structured in a tiered manner.