Ancient Instruments in the modern Classroom

The history of mathematics can enter classroom activity also by investigating copies of ancient instruments, reconstructed on the basis of historical sources. In some Museums of the History of Science there are beautiful collections of original instruments. Just to quote a couple of them in different parts of the world, we may refer to the Museo di Storia della Scienza, in Florence (Italy), to the Hilbert Raum of the Mathematics Institute in Goettingen (Germany) and to the Emperor Collection, stored in the Palace Museum of the Forbidden City in Beijing (China). Yet, because of the delicacy of those precious artefacts, visitors are not usually allowed to touch them. Hence an important part of the experience, namely the visual tactile feedback while handling the instrument, is not accessible to teachers and students. It would be really more useful to have rough yet working copies of them in the classroom. This is not an easy matter, especially for complex ones, but some specimens representative of important class of instruments could be built by teachers or students themselves.In this paper some examples of activity with working reconstruction of ancient instruments are reviewed.