2. The Ear and Hearing

3. If a tree falls in an empty forest, is there a sound? Yes!

4. Hearing terms to know Sound definition Outer, middle, inner ear Pinna, auditory canal, eardrum, ossicles (hammer, anvil, stirrup), cochlea, auditory nerve Amplitude, frequency, pitch, loudness

5. Hearing processes to know How sound moves through air. How sound is transmitted from outside your ear to your brain. How loud noises can damage your hearing.

6. Sound Definition “Vibrations that travel through the air or another medium and can be heard when they reach a person's or animal's ear.”

7. Sound moves through “air” similar to the way ripples in a pond move through water. Sound, and ripples, begin with a pressure event, or noise.

8. Pitch and Loudness in Sound Sound waves come in various frequencies and amplitudes, just like ocean waves come in different rates and heights. –High frequency sounds are higher pitch tones, low frequency sounds are lower pitch tones. –High frequency example: –Low frequency example: –High amplitude (height) sounds are louder, low amplitude sounds are quieter

9. High and Low Pitch High pitch Low pitch

10. Not all animals hear the same range of frequencies. Why didn’t all animals evolve to hear the same sounds? Moths hear very high frequency/high pitch sounds that we cannot hear. Low frequency High frequency

11. Loud and Quiet Amplitude of the sound wave determines loudness. Loudness is measured in decibels.

12. If you exceed the noise exposure time limits, you will damage your ears. NOISE EXPOSURE TIME LIMITATIONS Noise LevelExposure Limits 90 dB8 hrs 95 dB4 hrs 100 dB2 hours 105 dB1 hour 110 dB30 minutes 115 dB15 minutes GUNFIRE NOISE LEVELS.38 Spl.156 dB.44 Mag164 dB

13. Are Seahawk Games Safe for Your Ears?

14. Outer ear: filled with air Middle ear: filled with air and bone Inner ear: filled with fluid The Three Main Regions of the Ear

15. The Outer Ear The Outer Ear includes the Pinna, the Auditory Canal and the Tympanic Membrane (“Ear Drum”). Sound waves travel to, and vibrate the ear drum Auditory Canal

16. Function: The outermost part of the outer ear is called the pinna. This is the part of the ear that people can see. It collects, focuses and amplifies sound waves. Pinna

17. Fancy Pinna! Why do bats need such large pinna?

18. Yum, earwax! The outer ear includes earwax. Earwax contains chemicals that fight off infections that could hurt the skin inside the ear canal. It also collects dirt to help keep the ear canal clean.

19. The Middle Ear The middle ear's main job is to transmit and amplify the vibrations from the ear drum and deliver them to the inner ear. The eardrum vibrates with the sound, and pushes the three bones, or ossicles, of the middle ear. (The ossicles are the hammer, anvil and stirrup.) –This turns sound waves into mechanical movement. The ossicle motion pushes against the fluid of the inner ear, turning the motion into waves in a fluid.

20. The Three Bones! The hammer The anvil The stirrup Together, these work as a lever. They are pushed by the eardrum and they push against the inner ear. They are the three tiniest, most delicate bones in your body.

21. The ossicles. Malleus = hammer Incus = anvil Stapes = stirrup How to remember these three?  M.I.S. = H.A.S.

22. Review How does sound move from outside your ear to the inner ear, and what ear parts are involved?

23. The Inner Ear: Nerve Signals Start Here Sound comes into the inner ear as vibrations from the ossicles and enters the cochlea (say: ko-klee-uh), a small, curled tube in the inner ear. The cochlea is filled with liquid, which is set into motion, like a wave.

25. The cochlea is lined with tiny cells covered in tiny microscopic hairs. When sound reaches the cochlea, the liquid vibrations cause the hairs on the cells to move, creating nerve signals that the brain understands as sound. Cochlea are hairy!

26. Damage to your ability to hear... The hairs in your cochlea are connected to nerves. When there is too much vibration, like at a Justin Beiber concert, these hairs can be damaged and even break off. You cannot grow new hairs! This is like a storm tearing seaweed from the ocean floor during a storm.

27. Good sites for review How hearing works: http://www.gallaudet.edu/clerc_center/information_and_resources/in fo_to_go/hearing_loss_information/hearing_loss_for_older_children. html http://www.gallaudet.edu/clerc_center/information_and_resources/in fo_to_go/hearing_loss_information/hearing_loss_for_older_children. html Animations: http://www.wisc- online.com/objects/ViewObject.aspx?ID=AP1502http://www.wisc- online.com/objects/ViewObject.aspx?ID=AP1502 A hearing test video: http://www.youtube.com/watch?v=4G60hM1W_mk&feature=fvw http://www.youtube.com/watch?v=4G60hM1W_mk&feature=fvw A more advanced review animation: http://highered.mcgraw- hill.com/sites/0072437316/student_view0/chapter46/animations.html #http://highered.mcgraw- hill.com/sites/0072437316/student_view0/chapter46/animations.html #