1.THE EARTIM LILLEY 9LYear 9 Science Assignment:Sound Investigation-The Ear

2. THE EAR The Ear is a complex body part responsible for your sense of hearing. This video provides an introduction to the function, anatomy and science behind the ear.IF THIS VIDEO DOES NOT PLAY, FIND IT UNDER THE NAME THE EAR- INTRODUCTION.THIS VIDEO HAS SOUND. 3. FUNCTION OF THE EAR As stated in the video, the primary functionof the ear is to receive and decipher sound. However, the ear is also essential inmaintaining body control through balance. 4. THE EARHow does the ear receive and decipher sound? This video explains.IF THIS VIDEO DOES NOT PLAY, FIND IT UNDER THE NAME THE EAR-HOW IT WORKS. THIS VIDEO HAS SOUND. 5. HOW THE EAR WORKS After the sound has been converted intoelectrical signals, it travels to the brain. It is here that the brain deciphers thesound. The sound will be recognised by the brainbased on its frequency (pitch) and decibel(volume) of the sound. The ears are most sensitive to sounds thatare 3000 hertz. 6. SOUND WE CANT HEAR Depending on the species of an animal,different sounds of different frequencys canbe heard. Most humans can only hear sounds withinthe range of 20 hertz to 20000 hertz. Sounds under 20 hertz are calledinfrasound and over 20000 hertz are calledultrasound. Sounds under 0 decibels cannot be heard,and sounds over 120 decibels are felt as pain. 7. The Human Hearing CurveThis graph shows the sounds that are audible to humans. Thisgraph however is not true for everyone, as with age or hearingdamaged comes a decreased ability to hear high frequency and lowdecibel sounds. 8. How Does Sound Travel? We now know that humans can hear sound and how the ear receives sound, but how does sound reach the ear in the first place?IF THIS VIDEO DOES NOT PLAY, FIND IT UNDER THE NAME THE EAR-HOW DOES SOUND TRAVEL. THIS VIDEO HAS SOUND. 9. DAMAGE TO OUR EARS There are numerous infections, diseasesand physical harms that can cause damageto our ears. The most well known ear problem wouldbe partial to full deafness, which accordingto a 1998 study, affects 16.6% of Australiansover the age of 15. Another well known ear problem istinnitus, which is constant ringing in theear. 10. DAMAGE TO OUR EARS There are two types of hearing loss: Conductive Hearing Loss: When sound cannot move freely fromyour outer to inner ear. Sensorineural Hearing Loss: When there is damage to the pathwayfrom your inner ear to your brain. Hearing loss from both of these categoriesis called mixed hearing loss. Hearing loss in one ear is unilateral lossand in both ears is bilateral loss. 11. WARNINGCONTENT MAY DISGUST SOMEVIEWERSCLICK TO REMOVE BOXCholesteatomaCholesteatoma is a skin growth that can affect the middle ear andthe eardrum. If it is not treated or removed, it may spread to otherareas of the ear and further effect your hearing. 12. CAUSES OF HEARING LOSS The primary cause of hearing loss is age,however there are many other ways inwhich hearing can be damaged. Conductive Hearing Loss: Middle Ear Infection Glue-Ear (Build up of fluid in ear) Outer Ear Blockage Otosclerosis (Bone growth in middle ear that hardens Ossicles) Pierced Eardrum 13. Hearing DamageHearing damage can occur withlong term exposure to noises over85 decibels. Noise destroys thesensitive hairs in the ear that handlesound and hence destroy yourability to hear it. As shown in thechart opposite, just 4 hours ofcontinuous exposure to an 85decibel sound is enough to causepermanent damage. While this mayseem like a long time, people whowork long shifts in noisy workplacesare an example of someone whosehearing may be seriously damagedby noise. 14. CAUSES OF HEARING LOSS Sensorineural Hearing Loss: Long Term exposure to noises of 85 decibels Infections such as Rubella, Meningitis or Measles. Minieres Disease (A condition that affects your inner ear leading to hearing loss) Some medicines and cancer treatments. Acoustic neuroma (A benign tumour that affects the auditory nerve) Head Injury 15. RESTORING HEARINGOne way of restoring lost hearing is through the use of CochlearImplants. Commonly known as the Bionic Ear, it restores hearingthrough the use of a microphone, a speech processor, and a smallelectronic chip surgically implanted in your ear that stimulates theauditory nerve so you are able to hear once more. 16. LOOKING AFTER YOUR EARS There are various ways to eliminate eardamage risks. Reducing noise in the workplace through the replacement or repair of old and noisy machinery. Use of ear protection such as ear muffs or ear plugs. Limitation of exposure to sounds over 85 decibels. Fitting sound absorbing materials such as fabrics to the walls, doors and ceiling to absorb the noise. 17. BIBLIOGRAPHY Australian Hearing 2012, How do we hear?,accessed 04/05/2012 The Physics Classroom 2012, Sound Wavesand Music, accessed 04/05/2012, Restored Hearing 2012, Restoring Hearing,accessed 07/05/2012, Bupa Health 2012, Health Information,accessed 07/05/2012, 18. THANKS FOR WATCHING LISTENING!!!