In museums and science centres we engage our visitors through exhibitions and activities wherein they explore phenomena, representations and artifacts/specimens. Often, we present content to a passive audience, but then visitors miss the chance to really appreciate how scientists work – how they make phenomena understandable, prepare objects or specimens for display, how they research or use equipment and artifacts. There are, however, many opportunities for visitors to have real scientific experiences. In this session we will analyse some experiences developed by Parque de las Ciencias, Dasa, and the Natural History Museum and will discuss the challenges related to these activities.