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Sound Waves. Compressional Wave Mechanical Wave (must have a medium). Click here for demo of mechanical properties. [http://www.ccohs.ca/images/noise1.gif]. Speed of Sound. Speed of sound is constant in a given medium (chart pg. 359). [http://www.angelfire.com/scifi/dschlott/sSpeed.gif].
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Sound Waves • Compressional Wave • Mechanical Wave (must have a medium) Click here for demo of mechanical properties. [http://www.ccohs.ca/images/noise1.gif]
Speed of Sound • Speed of sound is constant in a given medium (chart pg. 359) [http://www.angelfire.com/scifi/dschlott/sSpeed.gif]
Speed of Sound • The speed of sound increases when the temperature is warmer. • This is a direct relationship.
Speed of Sound • Vin air = 331 + 0.6(TC) • Units are in m/s
Speed of Sound • Example: How fast does a sound wave move when air temperature is 10 °C? • V = 331 + 0.6 (10) • V = 331 + 6 • V = 337 m/s
Speed of Sound • Sonic Boom – Object is traveling faster than the speed of sound. • MACH scale [http://community.webshots.com/photo/29220851/29224250NbiEGaCAdC#]
Click here for a Sonic Boom video [http://www.grc.nasa.gov/WWW/K-12/airplane/Images/mach.gif]
Sound Waves and Hearing • Outer Ear – visible part of ear, ear canal and eardrum. (Pg. 361) • Energy from sound waves make the eardrum vibrate.
Sound Waves and Hearing • Middle Ear – Bones called the hammer, anvil, and stirrup amplify the sound.
Sound Waves and Hearing • Inner Ear – The cochlea sends impulses to the brain.
Sound Waves and Hearing • Hearing loss is usually caused by damage to the hair cells in the cochlea. [https://secure.dca.net/nohr/Nohrcontactimages/Hair-cellbk.jpg]
[http://www.sickkids.ca/auditorysciencelab/images/ohc_mild_sml.jpg][http://www.sickkids.ca/auditorysciencelab/images/ohc_mild_sml.jpg]
Intensity • How much energy a sound wave carries over time. • Determines how far it can travel. [http://www.safetyline.wa.gov.au/institute/level2/course18/lecture54/images/noise11b.gif]
Loudness • The human perception of intensity. • Measured in decibels (dB)
[http://www.ednasia.com/cmsimages/issue0410cs5.gif] [http://www.hearinginseattle.com/images/decibelbars1.jpg]