In this work, we present an experimental approximation to the study of the phenomenon of radioactivity in secondary schools, taking as an analogy the process of release of carbon dioxide in a carbonated beverage. In this way, we intend to facilitate the approach to the mathematical formalism and to the graphical description of this phenomenon, as well as to the understanding of its most important magnitudes: activity or decay rate, decay constant, half-life time, and mean lifetime.