Sound Reproduction

A Year 11 module from the Salters’ Key Stage Four double award science course. The science content of this module covers electromagnetism, the inductive effect and the motor effect. These topics are developed in the context of recording and reproducing sound. Students begin by recording and playing back their own voices. A circus of practical activities is used to revise basic ideas about the nature of sound and the terminology used to describe longitudinal and transverse waves. There is an exercise on the gradual deterioration of sound on repeated re-recording. Text based exercises revise the properties of magnets. Students make and test a loudspeaker. The magnetic field around a solenoid is studied. Diffraction of sound is demonstrated and linked to the use of speakers of different sizes. The inductive effect is demonstrated and linked to play-back of magnetic tape. The moving coil microphone is shown to be a loudspeaker driven in reverse. The operation of 'swipe cards' is modelled. Analogue and digital signals are compared and students carry out a signal recognition exercise. They consider recording and playback of CDs. Students build and test an electric motor and consider its uses. The module concludes with a review of the range of effects studied.

Section 1: Sound systems Students begin by recording and playing back their own voices. A circus of practical activities is used to revise basic ideas about the nature of sound and the terminology used to describe waves. There is an exercise on the gradual deterioration of sound on repeated re-recording.

Section 2: How do loudspeakers work?Text based exercises revise the properties of magnets. Students make and test a loudspeaker. The magnetic field around a solenoid is studied. Diffraction of sound is demonstrated and linked to the use of speakers of different sizes.

Section 3: Using movement to induce signals The inductive effect is demonstrated and linked to play-back of magnetic tape. The moving coil microphone is shown to be a loudspeaker driven in reverse. The operation of “swipe cards” is modelled. 

Section 4: Digital systems Analogue and digital signals are compared and students carry out a signal recognition exercise. They consider recording and playback of CDs. 

Section 5: What makes electric motors work?Students build and test an electric motor and consider its uses. The module concludes with a review of the range of effects studied.