We propose a simple demonstration to explain to prospective primary teachers the basic ideas behind Faraday´s law of induction and the generation of electricity. In this conceptual activity, a rotating magnetized fidget spinner induces voltage in a copper coil. In an attempt to make this demonstration more motivating and surprising, the voltage was not measured and analyzed with a voltmeter; instead, we used a loudspeaker to listen to and understand the induction of electricity. It is therefore a variation of the classical experiment of the bar magnet sweeping through a solenoid.
