The bulk of matter is invisible, as it (almost) does not emit any radiation. We know them as dark matter. How can we explore and measure them? This is one objective of the ATLAS@CERN experiment to gain clarity and this should be brought closer to the students in this mission. Atlas@Cern Portal: http://www.learningwithatlas-portal.eu/ Atlas@Cern Österreich: http://www.virtuelleschule.at/atlas