Selecting and developing activities for hearing things

Teacher Tip: Based on the Physics Narrative and the Teaching and Learning Issues

Ideas to emphasise here

• the physical aspect of the transmission of sound
• the source-medium-detector model
• the spreading of the vibrations
• the to and fro vibrations
• prepare the ground for frequency and amplitude being the fundamental characteristics
• vibrating objects, as sources and detectors
• reinforce the source-medium-detector model
• represent the vibrations of the source
• represent the vibrations in the medium
• represent the vibrations of the detector
• account for reductions in intensity with distance from the source
• link delays in hearing sounds to the trip time of propagation from the source
• show sounds travelling through solids and liquids, as well as gases

Teacher Tip: Work through the Physics Narrative to find these lines of thinking worked out and then look in the Teaching Approaches for some examples of activities.

Strategies for supporting learning

• put the source-medium-detector model to use
• connect vibrating objects to travelling vibrations
• connect hearing to the source-medium-detector model
• separate the to and fro movement of the particles that forms the vibration from the propagation of the vibration, which is also a movement
• showing large-scale, slow vibrations producing a sound
• emphasising that all sounds have a source
• tracing the chain from source to detector, via medium, often
• explore the range of hearing, along both the amplitude and frequency axes
• connect human hearing to what other species can hear
• ensure that the need for particles as a medium is always there
• link each sound heard back to the source, via the medium

Teacher Tip: These are all related to findings about children's ideas from research. The teaching activities will provide some suggestions. So will colleagues, near and far.

Avoid these

• using specious energy descriptions
• drawing or showing transverse waveforms
• asserting that sound is a wave without clarifying explanation of the idea of a wave – this is hard
• showing waveforms on an oscilloscope or computer
• introducing wavelength

Teacher Tip: These difficulties are distilled from: the research findings; the practice of well-connected teachers with expertise; issues intrinsic to representing the physics well.