Today we will be looking at sound and hearing. Answer the following in your books:

1. What layers make up the ear drum?
2. What unit measures the loudness of sound (NOT amplitude!)?
3. How loud is a train going past you? How long can you hear this loud noise without damaging your ears?
4. What range of sounds can human ears hear?
5. Which animal can hear the highest sounds? What is the lowest frequency a cat can hear?
6. Watch this video about hearing loss. What can cause hearing loss?
7. What is the scientific name for hearing loss due to hearing loud noises?
8. Extension - What is SONAR? What is it used for? How does it work?