This paper starts from the fact that the teaching of electrostatics is becoming increasingly apart from the phenomenology in which it roots. Investigating the history of electroscope we try to show how some ideas as important as charge, potential and electric capacity had their origins linked to the use of such an instrument. Beyond the assigned important historical details, the history of electroscope can also reveal us something of unquestionable philosophical value in the teaching of physics: the extent to which the observation of electrical phenomena were always theoretically laden.
