1. Dangerous Sound Lesson aims To learn how sound can be dangerous and what can be done to reduce the risks of hearing damage

2. Learning outcomes By the end of the lesson you should State that loud sounds can damage hearing Compare sound levels using the decibel scale Describe how hearing can be impaired using ear model Describe how to reduce noise pollution

3. How are loud sounds made? How can the loudness of a sound be measured? Why are very loud sounds dangerous? What is the easiest way to quieten sounds?

4. We can use a sound level meter to measures sounds

5. Sound levels

6. Sound : How loud are sounds? 150 140 120 100 80 60 40 20 10 0 Permanent ear damage Can just be heard Aircraft overhead Personal stereo A circular saw at 2m Loud bell Pin being dropped Quiet countryside dB Can damage Hearing

7. Explaining noise Study this picture and read the comments Read pages 105-106

8. What is noise? A noise is any unwanted sound. What you might not consider noise, loud music for example, other people might. What are the effects of noise? 1._________ 2._________ 3._________ 4._________ Nausea Vomiting Headaches Deafness How can you reduce the effects of loud noise? 1._________________ 2._________________ 3.___________________ _______________ Ear protectors Putting noisy machinery in insulated rooms Double glazing

9. What is noise pollution? How can noise pollution be reduced? Explain how soft materials quieten sounds

10. What is the upper range of human hearing? A.20 Hz B.200 Hz C.2 000 Hz D.20 000 Hz

11. Measuring sound How does this compare to the graph for our lesson?

12. Research the reasons for damaged hearing www.evelyn.co.uk http://www.hse.gov.uk/noise/index.htm Pages 107 Spectrum Homework: research the factors that affect the speed of sound explain these in a poster