  Experiments concerning the physics of cosmic rays offer to high-school
teachers and students a relatively easy approach to the field of research in
high energy physics. The detection of cosmic rays does not necessarily require
the use of sophisticated equipment, and various properties of the cosmic
radiation can be observed and analysed even by the use of a single Geiger
counter. Nevertheless, the variety of such kind of experiments and the results
obtained are limited because of the inclusive nature of these measurements. A
significant improvement may be obtained when two or more Geiger counters are
operated in coincidence. In this paper we discuss the potential of performing
educational cosmic ray experiments with Geiger counters. In order to show also
the educational value of coincidence techniques, preliminary results of cosmic
ray experiments carried out by the use of a simple coincidence circuit are
briefly discussed.
