Finding the Target Solution and its Concentration: A Chemistry Escape Room

Abstract

Exploring secrets and solving puzzles in a detective-like manner can be highly motivating and engaging. Chemical puzzles offer a suitable framework for such inquiry-based learning experiences. In the work presented here, participants investigate four colourless solutions in a mini escape room that lasts approximately 15–25 minutes. According to the introductory information, one of the four solutions is the target solution and is described as being neutral with respect to pH while exhibiting high electrical conductivity. In addition, participants are asked to determine the concentration of this solution. A pH universal indicator paper and a conductivity meter with a sensor are provided as experimental tools. At first glance, all four numbered solutions appear identical, which requires the participants to proceed systematically. The investigation typically begins with cautious sensory examination. One solution can be excluded immediately due to its strong vinegar-like smell, indicating an acidic character. Further pH measurements allow the exclusion of a basic solution. Finally, conductivity measurements reveal the target solution as electrically conductive while remaining pH-neutral. This first stage already demands organised testing, careful observation, and teamwork. After identifying the correct solution, participants must determine its density. To do so, there are three play versions how to reveal the identity of the solution as aqueous sodium chloride. Entering its molar mass as a three-digit code into a fake dictionary box leads to a densitometer spindle. Following the information at the station, participants perform the density measurement and determine its concentration by using a diagram correlating concentration with density. The result serves as code for a final box containing a small “treasure”. This escape room has been successfully implemented in various educational contexts, including student motivation and team-building seminars, university research nights with mostly families, and workshops at children’s university workshops with participants aged 6–12 years. Feedback has been consistently positive. The activity is perceived as entertaining, accessible, and appropriately challenging, while fostering key competencies such as curiosity, logical reasoning, organised experimentation, and collaborative problem-solving using familiar chemicals.