1. What are some practical ways we use sound energy? The Human Ear

2. Introduction  Your ear converts sound waves into nerve impulses that your brain interprets.

3. Parts of the Ear  The Outer Ear Contains the pinna, ear canal and ear drum  The Middle Ear Contains three bones: hammer, anvil & stirrup  The Inner Ear Contains the cochlea and auditory nerve

5. The Outer Ear  The pinna is specially shaped to gather and focus sound waves and direct them into the ear  The ear canal is a hollow tube that carries the sound waves to the ear drum  The sound waves hit the ear drum, causing it to vibrate. The ear drum transmits these vibrations into the inner ear where they are amplified.

6. The Middle Ear  Has the smallest bones in the human body: hammer, anvil and stirrup  Their job is to amplify the vibrations of the eardrum and transmit it into the inner ear.

7. The Inner Ear  The cochlea is a snail-shaped tube that is lined with receptors that respond to sound  The receptors are tiny hair cells that shake back and forth in response to sound waves  When they shake, the hair cells create nerve impulses which go to the brain along the auditory nerve

8. Anatomy of the Human Ear

9. High vs. Low Sounds  High pitch sound carry more energy and travel further into the cochlea  Lower pitch sounds carry less energy and don’t travel as far into the cochlea

10. Intensity and Loudness  The intensity of a sound wave is the amount of energy the wave carries per second through a unit area.  Loudness, or sound level, is measured in decibels (dB)

12. SoundLoudness (dbs) Hearing Damage Average Home 40-50 Loud Music 90-100 After long exposure Rock Concert 115-120 Progressive Jet Engine 120-170 Pain Space shuttle engine 200 Immediate and irreversible

13. Frequency  Frequency is measured in Hertz (Hz)  The frequency of a sound wave is the number of vibrations that occur per second Meaning, a frequency of 50 Hz means fifty vibrations per second.  People hear sounds with frequencies between 20 HZ and 20,000Hz.

14. Ultrasound - sound waves with frequencies above the normal human range of hearing. Infrasound - sounds with frequencies below the normal human range of hearing.

15.  http://www.oprah.com/oprahshow/Dr-Oz- Goes-Inside-the-Human-Ear-Video http://www.oprah.com/oprahshow/Dr-Oz- Goes-Inside-the-Human-Ear-Video  http://www.noiseaddicts.com/2009/03/ca n-you-hear-this-hearing-test/ http://www.noiseaddicts.com/2009/03/ca n-you-hear-this-hearing-test/  http://www.noiseaddicts.com/2009/02/he aring-test-hear-like-teenager/ http://www.noiseaddicts.com/2009/02/he aring-test-hear-like-teenager/  http://www.betterhearing.org/hearing_los s/how_we_hear/virtualeartour.swf http://www.betterhearing.org/hearing_los s/how_we_hear/virtualeartour.swf  http://video.about.com/pediatrics/Ear- Pressure.htm