Science 4th grade | UNIT 4: Sound 4.6 Muffling sounds
There are some sounds that we don't like or sounds that are too loud. We can 1 muffle sounds that we don't want to hear. This means that we make the sounds quieter and less clear.
Loud sounds can hurt our ears. Some people work in very noisy places. They need to protect their ears. They wear ear defenders to muffle sound.
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Ways to muffle sound
We fit silencers to cars, trucks and motor cycles to muffle the sounds of their engines.
In buildings we use carpets and curtains to stop noise. Sometimes the spaces between walls are filled with materials that don't let noise through.
Activity 4.6 (Finding out which material muffles sound the best)
You will need: different materials - a source of sound - a shoe box with lid - a sound level meter (if available)
Predict which material will muffle sound the best. Place the sound source in the box. Pack one of the materials around the sound source in the box. Then place the lid on the box. Stand about 1 m away from the box and listen to the sound. Is the sound loud or soft?
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If you have a sound level meter, measure the sound volume and record it. Repeat the activity with the other materials. Present your results in a table.
Questions
1) Which material muffled sound the best? Why do you think so?
2) Was your prediction correct?
3) Is this investigation a fair test? Explain why or why not.