Cosmic rays are one of the few opportunities a secondary-school student has to come into direct
contact with particle physics, and outreach programmes built around observing them have appeared
in many countries. What distinguishes the programme reported here is where the observation
happens. Most outreach reaches students through their school, or gathers them at a laboratory for
a one-day event; we instead support individual students directly, in their own homes, over more
than a year. Students assemble a palm-sized scintillator-and-SiPM detector themselves and take it
home in a form that is deliberately not a black box, with university and graduate-student mentors
accompanying them online. More than 300 detectors have been lent free of charge, about 100
students continue measuring for over a year, and they have proposed close to 100 research projects
of their own. In 2026 two peer-reviewed papers appeared with high-school students as first authors.
Through IPPOG’s Global Cosmics group we also meet twice a year with the cosmic-ray outreach
groups of 19 countries, and exchange between the students themselves has grown out of those
meetings. To create more opportunities of that kind, we visit countries new to the activity —
Senegal, Argentina, and the Dominican Republic among them — running hands-on cosmic-ray
measurement workshops and installing detectors there.