Why do mobile phones contain gold, silver and other precious metals or rare earths? During Girls' Day on April 25, 2013, 19 girls between 10 and 13 years of age have got to the bottom of this question at the Production Technology Centre (PTZ) Berlin. After learning some things about rare resources, they took matters in their own hands. In small groups the girls disassembled old mobile phones and identified the contained raw materials with the help of a "Raw Materials Briefcase" that was developed at the IASS Potsdam. In their progress, they discovered which different raw materials are put into mobile phones and how much energy is needed for their processing.

Afterwards, the girls could try out different technological solutions for sustainable production in the PTZ Test field: They manufactured wristbands with a 3D printer, experimented with solar energy and cleaned with dry-ice blasting – an environmentally friendly industrial cleaning process.