Abstract
Electropotential series is an important topic within all levels of the chemistry teaching. The article is focused on the combination of common chemical topic and inquiry-based science education with mystery (TEMI - teaching enquiry with mysteries incorporated).
The result of the work is a teaching material, which is adjusted and modified and could be used as a laboratory theme for teachers not only at the high school. At the beginning the pupils actively familiarize with the story about murders of the jeweler Beketov and the police commissioner Markovnikov.
In the second part they finish the experiments that Markovnikov hadn't finished and which lead to revelation of the murder. In the end the pupils discover which metal supplier killed Beketov and Markovnikov just by using the chemical experiment methods.
The lesson was carried out at the secondary school, high school as well as in the course of lifelogng learning. For all participants the conclusion was everytime surprising.