Science at key stage 3 (Year 8)
Unit 8L: Sound and hearing
Section 9: a. Can sound be dangerous?
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Objectives |
| Children should learn: |
- how to compare loudness
- how to plan to collect data
- about reasons for repeating measurements
- to present data appropriately
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Activities |
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Outcomes |
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Children: |
- Raise issues of noise pollution,
eg near airports, due to traffic and listening to pop music. Demonstrate use of a sound-level meter. Ask pupils about an alternative method of comparing sounds that relies on the way loudness diminishes with distance,
eg measure the distance at which the sound first can no longer be heard. Ask pupils to investigate a question,
eg
- survey the loudness of sounds at different locations around the school or over time in their own classroom
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compare the loudness of sounds from personal stereos, eg set at the level at which pupils like to listen
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investigate the effects of sound insulation, eg with a clock in a box filled with different absorbent materials
- Help pupils to plan the measurements (including repeat measurements) they will take and the way they will record and present their data.
- Present data from secondary sources on sound and recommended safe levels. Ask pupils to draw up a list of sound levels for common sounds.
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- use a sound-level meter or other method of comparing sounds
- make a sufficient number and range of measurements
- present data and draw appropriate conclusions
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Points to note |
- The decibel (dB) scale measures differences between sound power levels. It is expressed logarithmically to reflect the ear's response. Sound-level meters use a modified scale called dB(A), which allows for the ear's different sensitivity to different frequencies. Strictly speaking, loudness is measured in phons, but at this level pupils can use the sound-level meter values as measures of loudness. A datalogger could be used with the meter for measurements over time.
- This work could be linked with unit 7 'Measuring physical data' in the ICT scheme of work.
Safety
- supervision is required for any work near traffic. Follow employer's guidelines for fieldwork. Ensure sound levels are within permitted limits. Pupils' plans must be checked for health and safety before practical work begins
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This unit is divided into sections. Each section contains a sequence of
activities with related objectives and outcomes. You can view this unit by
moving through the sections or print/download the whole unit.
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