Science communication has traditionally been seen as a means of crossing the boundary of science: moving scientific knowledge into the public. This paper presents an alternative understanding. Drawing upon a particular case of social science communication in the form of an interactive installation about the social responsibility of science, it develops the concept of boundary space where phenomena can simultaneously belong to science and nonscience. In addition, the paper describes how the installation functions as a space for interaction between knowledge communication and knowledge production. The paper argues that we should understand science communication as a social practice, which allows scientists and nonscientists to cooperate in performing science as an important part of society. The aim is to add a new kind of analysis to traditional criticisms of deficit-thinking and popularization by asking what can we say more about science communication if we understand it as part of (rather than separated in time and space from) science as a social activity.