Klaus Ruppersberg -born in Cologne- has got 24 years of experience of teaching chemistry and biology at different schools and to different types of pupils. Since 2014, he is based at the Leibniz Institute for Science and Mathematics Education at the University of Kiel/ Germany. His main interests are the teaching and learning of complex chemical knowledge and the development of demonstrative and safe experiments. Currently he is working on a special mechanism of a detection reaction for lactose and maltose, i.e. the Woehlk reaction.