Dangerous Sound

Lesson aims

To learn how sound can be dangerous and what can be done to reduce the risks of hearing damage

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

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?

We can use a sound level meter to measures sounds

Sound levels

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

Explaining noiseStudy this picture and read the comments

Read pages 105-106

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

What is noise pollution?

How can noise pollution be reduced? Explain how soft materials quieten

sounds

What is the upper range of human hearing?

A. 20 Hz

B. 200 Hz

C. 2 000 Hz

D. 20 000 Hz

Measuring sound

How does this compare to the graph for our lesson?

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