We describe a hands-on accurate demonstrator for cosmic rays realized by six
high school students, whose main aim is to show the relevance and the
functioning of the principal parts of a cosmic rays telescope (muon detector),
with the help of two large size wooden artifacts. The first one points out how
cosmic rays can be tracked in a muon telescope, while the other one shows the
key avalanche process of electronic ionization that effectively allows muon
detection through a photomultiplier. Incoming cosmic rays are visualized in
terms of laser beams, whose 3D trajectory is highlighted by the turning on of
LEDs on two orthogonal matrices. Instead the avalanche ionization process is
demonstrated through the avalanche falling of glass marbles on an inclined
plane, finally turning on a LED. A pictured poster accompanying the
demonstrator is as well effective in assisting cosmic rays demonstration and
its detection. The success of the demonstrator has been fully proven by general
public during a Science Festival, the corresponding project winning the
Honorable Mention in a dedicated competition.Comment: Latex, 8 pages, 6 figures; to be published in Physics Educatio
