A last generation weather radar is being installed in the East of Paris. This measuring device will bring important improvements to urban water management in several areas of the city that are exposed to flood risk. In this context, building a dialogue with concerned citizen is highly important. For this reason, the team of researchers in charge of the project went out the laboratory to meet families in a important local festival, and students in the schools of Paris suburbs. Through interactive presentations and educational games, the researchers from École des Ponts ParisTech together with two brilliant " Crazy Scientists " , explained how a X-band radar works and how it can reduce the risks of floods and water pollution in the city. The itinerant laboratory is made possible through the Chair Hydrology for a Resilient Cities and the following research projects: Radx@IdF, Interreg RainGain, Climate-KIC BlueGreenDream.