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Sound homework
- 1. 6 6.9 Sound experiment A group of pupils did an experiment in a playground. A map of the playground is shown below. The pupils were investigating the way that walls cast a ‘sound shadow’. They made a standard volume of sound by dropping a 1 kg mass onto a sheet of steel. The volume of the sound was measured using a sound meter at the places labelled A to H on the map. PLAYGROUND A B C D positions of readings E minibus sound F garage source G H school building The measurements that the pupils recorded are shown below. Position A B C D E F G H Reading 1 5.6 5.0 5.2 5.7 3.2 2.4 2.0 3.6 (decibels) Reading 2 5.0 5.0 5.1 6.0 0.3 3.2 1.9 3.8 (decibels) Reading 3 5.2 5.0 5.0 5.8 3.1 2.2 2.0 3.7 (decibels) Average 5.3 5.0 5.1 5.8 3.2 2.3 2.0 3.7 (decibels) 1 Produce a bar chart of the results using the average values. [Level 4] 2 The pupils thought some of the results were very odd and decided not to use them in the averages they calculated. a Which results do you think they thought were odd. Explain why? [Level 5] b Do you think the pupils were right to ignore these results. Explain why? [Level 5]
- 2. 6 6.9 Sound experiment 3 The pupils were also surprised at the readings they got for position H. They did not think there was an error but they could not explain why the results behaved in this way. a Why did the pupils not think the results were an error? [Level 5] b Why were the pupils surprised by the results? [Level 5] c What explanation can you suggest for the results? [Level 6] 4 Sound barriers at the side of motorways are a simple solution to road traffic noise that would otherwise bother people living in nearby houses. Inspectors sometimes check the noise levels near houses that are protected by a barrier. Describe five factors that the inspectors should take into account when taking their readings, to make sure that they are getting measurements that really reflect the noise that the residents hear. Explain what effect you think these factors would have on the recorded noise levels. [Level 7]