A ‘sparkling’ low-cost revisitation of the historical Hertz’s experiment

Abstract

Electromagnetic phenomena involve abstract concepts and models that are particularly problematic for students, especially in the field of electromagnetic (EM) waves. In particular, for these abstract topics it is difficult to plan real experiments that offer the possibility to introduce the basic related concepts. A valid support might come from the revisitation of historical experiments, whose value have been demonstrated from an educational point of view.In this frontline we have planned an educational real-time experiment, which allows students to get in touch with the basic phenomenology of EM waves. It is a modern revisitation of the historical Hertz's experiment that offers the possibility (from a qualitative point of view) to reproduce the Hertz's ideas using low cost and easy to find materials, showing an easy way to generate and to detect an electromagnetic wave. Moreover, the same kind of low cost setup allows performing quantitative measures if coupled with a digital acquisition module, offering the possibility to characterise the main conceptual aspects of an electromagnetic wave, such as the signal's dependence on the distance between transmitter and receiver or as the concept (otherwise abstract) of polarisation.

Modern demonstration experiments for H Hertz’s experimental study

“…Similar devices with 160-170 MHz frequencies are described in [14]. Virtual demonstrations using a spark transmitter and receiver are discussed in [15,16].…”

Wireless at its origin

“…The basic understanding of electromagnetic waves is crucial for students of all age, not only from the point of view of their scientific education but also for their understanding of the wireless connected world we are living in. However, concepts of electromagnetisms are generally too abstract [1,2], so that many students (especially the youngest ones) do not develop a functional understanding of these topics [2]. For this reason, a number of educational materials and experimental set-ups have been developed to help students overcoming these difficulties [1,3].…”

“…However, concepts of electromagnetisms are generally too abstract [1,2], so that many students (especially the youngest ones) do not develop a functional understanding of these topics [2]. For this reason, a number of educational materials and experimental set-ups have been developed to help students overcoming these difficulties [1,3]. These experiments allow for an improved understanding * Author to whom any correspondence should be addressed.…”

“…These experiments allow for an improved understanding * Author to whom any correspondence should be addressed. of electromagnetic wave concepts, such as polarization, interference etc… [1], often using low cost materials, like for example a piezoelectric gas lighter, which is commonly used to produce the electromagnetic waves detected by simple dipole systems or by a coherer [1,3]. Moreover, many of these set-ups aim at revisiting experiments that made the history of science, like for example the Hertz's experiments [1].…”

Hands-on activity using the amplitude and frequency of electromagnetic waves to demonstrate the principle of information transfer

“…Gülçiçek et al 2018, Hellesund 2019, Thy and Iwayama 2021. In contrast, EM waves are more abstract involving the oscillation of electric and magnetic fields (Kneubil et al 2015, Bozzo et al 2017. To help students visualise EM waves, pictures of sinusoidal plane waves with oscillating electric and magnetic fields are shown in many physics textbooks (e.g.…”