Chemsim is an app that allows you to understand the degree of ionisation strong and weak acids and bases produce in aqueous solutions, and to draw conclusions about the conductivity of such solutions. In addition, users can set up and try out the experiment themselves in a simulation. Various solutions are available in the experimental setup whose conductivity can be tested. The conductivity of a solution is shown with a light-emitting diode. The more conductive a solution is due to a higher degree of ionisation, the brighter the diode glows. The app also includes extensive in-app documentation and help on how to use it. People with disabilities can also use this app because it is designed to be barrier-free.