It is important to transmit the science developed in a research institution to the public. This transmission helps to increase the scientific culture of the general public, and also can help to awake scientific vocations in the kids. During this talk I will present several actions carried out at the Observatoire de la Côte d’Azur (Nice, France), to bring astronomy to the school children and also to the general public. I will talk about the EduCosmos project, where school children observe with a 1m telescope for a scientific project carried out at the Observatoire de la Côte d’Azur. I will also present several practical examples of specific activities used to explain astronomical concepts as parallax, light interference or the resolution of a telescope.