The transition of many educational activities from in-presence to online, due to the Covid-19 emergency, has caused various difficulties to students, especially with regards to maintaining concentration. Even and especially in online mode, it is thus important to pay attention to the interaction with participants. In this context, the Department of Mathematics and Physics of Roma Tre University has proposed a series of activities dedicated to schools that have proven to be able to guarantee the engagement of the participants, also thanks to the game-based learning platform Kahoot!.